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Dissertations / Theses on the topic 'Cancer - Radiotherapy treatment'
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Cha, Kyungduck. "Cancer treatment optimization." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22604.
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Thesis (Ph. D.)--Industrial and Systems Engineering, Georgia Institute of Technology, 2008.Committee Chair: Lee, Eva K.; Committee Member: Barnes, Earl; Committee Member: Hertel, Nolan E.; Committee Member: Johnson, Ellis; Committee Member: Monteiro, Renato D.C.
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Williamson, Raymond Allan. "An experimental study of the use of hyperbaric oxygen treatment to reduce the side effects of radiation treatment for malignant disease." University of Western Australia. School of Anatomy and Human Biology, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0063.
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[Truncated abstract] Therapeutic Radiation has been used for the treatment of cancer and other diseases for nearly a century. Over the past 20 years, Hyperbaric Oxygen Treatment (HBOT) has been used to assist wound healing in the prevention and treatment of the more severe complications associated with the side effects of Therapeutic Radiation Treatment (TRT). The use of HBOT is based on the premise that increased oxygen tissue tension aids wound healing by increasing the hypoxic gradient and stimulating angiogenesis and fibroblast differentiation. As it takes up to 6 months for a hypoxic state to develop in treated tissue, following radiation treatment, current recommendations for HBOT state that it is not effective until after this time. During this 6 month period, immediately following TRT, many specialized tissues in or adjacent to the field of irradiation, such as salivary glands and bone, are damaged due to a progressive thickening of arteries and fibrosis, and these tissues are never replaced. Currently, HBOT is used to treat the complications of TRT, but it would be far better if they could be prevented . . . In summary, this experimental model has fulfilled its prime objective of demonstrating that HBOT is effective in reducing the long-term side effects of therapeutic radiation treatment in normal tissue, when given one week after the completion of the radiation treatment and statistically disproves the Null Hypothesis that there is no difference in the incidence of postoperative complications or morbidity of TRT when 20 intermittent daily HBOT are started one week after completion of TRT. This project provides an extensive description of the histological process and also proposes a hypothesis for the molecular events that may be taking place.
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Wey, Mark Tao Teong. "DNA repair in bladder cancer predisposition and radiotherapy treatment response." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/8087/.
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The genetic contribution to bladder cancer risk remains undetermined, while the role of radiotherapy versus surgery in muscle-invasive bladder cancer (MIBC) treatment is hotly debated with the need for predictive biomarkers of treatment response. DNA repair pathways are involved in repairing DNA damage from carcinogens thus preventing carcinogenesis, but also form one of the 5 R’s of radiobiology for determining cancer response to radiotherapy. The aims of this project were: 1) To study the contribution of germline DNA repair gene variants, specifically rare variants (RV) and 3’-untranslated region (3’UTR) single nucleotide polymorphisms (SNP), on bladder cancer risk. 2) To investigate the predictive value of germline DNA repair gene variants and tumour DNA repair protein expression on radiotherapy outcomes in MIBC. RVs can only be identified by sequencing so a developmental multiplexed next-generation sequencing (NGS) project was undertaken, identifying two approaches, with the choice of method based on balancing costs and labour versus accuracy and data needed. Using these methods, candidate RVs were identified in the DNA repair genes, MUTYH and XPC, with XPC RVs being associated with an increased bladder cancer risk (P=0.008) independent of previously identified GWAS SNPs. Putatively functional DNA repair gene 3’UTR SNPs, PARP1 rs8679 and RAD51 rs7180135, were found to increase bladder cancer risk (P=0.05) and predict improved survival following radiotherapy (P=0.01) respectively. Multiplexed NGS of MRE11A identified rs1805363 to be predictive of survival following radiotherapy (P=0.001) but not surgery (P=0.89), and to affect MRE11A isoform expression. Tumour DNA repair protein expression of CtIP, MUTYH and XPC were not found to predict survival following radiotherapy. This study demonstrated the contribution of DNA repair gene variants in bladder cancer risk and predicting radiotherapy response. These findings could contribute to the goal of personalised medicine for targeted primary prevention, early diagnosis and treatment individualisation.
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Fokas, Emmanouil. "Targeting the PI3K/mTOR and ATK/Chk1 pathways to improve radiation efficacy for cancer therapy." Thesis, University of Oxford, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572788.
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The purpose of the present thesis was to better understand the effect of targeting key biological mechanisms in order to improve radiotherapy response. Two important and distinct pathways were targeted using novel agents: (1) the phosphoinoside-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway; (2) the ataxia telangiectasia-mutated-Rad3-related (ATR)/Chkl pathway. The role of the PI3K1mTOR signalling pathway in tumour radiosensitivity and tumour microerivlronment (TME) was examined using three, recently-developed signalling inhibitors obtained from Novartis Pharma: NVP-BEZ235 (dual PI3K1mTOR inhibitor), NVP-BGT226 (dual PI3K1mTOR inhibitor) and NVP-BKM120 (single PI3K inhibitor). The radiosensitising potential of NVP-BEZ235 and NVP-BGT226 was demonstrated in tumour and endothelial cells. Additionally, a thorough research into the effects ofNVP-BKM120 and NVP-BEZ235 on TME showed that oncogenic signalling inhibitors can improve vascular morphology and increase tumour oxygenation and perfusion in tumour xenograft models, resulting in improved radiation response. Furthermore, a highly potent and selective A TR inhibitor, VE-822, that was obtained from Vertex Pharmaceuticals (Europe) Ltd, was tested in pancreatic ductal adenocarcinoma (PDAC) cells and tumour xenograft models. A TR inhibition by VE-822 resulted in sensitisation of tumour cells but not normal cells to radiation and gemcitabine. Similarly, VE-822 strongly enhanced radiation- and chemoradiation-induced tumour growth delay in tumour xenograft models. Importantly, VE-822 did not potentiate radiation-induced gastrointestinal tract epithelial damage. To summarize, the impact of targeting two distinct pathways in combination with radiation and chemoradiation was explored. Inhibition of the PI3K1mTOR and ATRlChkl signalling pathways increases response of tumours to radiotherapy they and might be promising targeting strategies for cancer treatment. Our findings have considerable translational implications and future clinical trials should aim to validate these observations.
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Murray, Louise Janet. "Optimising treatment outcomes using Stereotactic Body Radiotherapy (SBRT) for prostate cancer." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/8666/.
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Aims: to optimise linear accelerator-based prostate stereotactic ablative radiotherapy (SABR) through planning studies, tumour control probability (TCP) and normal tissue complication probability (NTCP) calculations and radiation-induced second primary cancer (RISPC) risk assessment. Methods: A planning study was performed to develop a class solution for prostate SABR. A second planning study delivered boosts to dominant intra-prostatic lesions (DILs) and TCP and NTCP were calculated. A third planning study compared prostate SABR planning using flattened and flattening filter free (FFF) beams. A systematic review examined RISPC risk following prostate radiotherapy. A final study estimated RISPC risks following prostate SABR in comparison to other contemporary radiation techniques. Results: Prostate SABR was optimal using a single anterior arc which resulted in highly conformal plans, lower rectal doses and improved delivery times and monitor unit requirements for most patients. Boosting DILs resulted in small TCP increases, but the benefit was offset by increases in NTCP. SABR to the whole prostate without DIL boosting resulted in high TCP and low NTCP. Plans using flattened and FFF beams were dosimetrically similar but FFF resulted in reduced delivery times. Clinical evidence, largely based on older radiation techniques, suggests that prostate radiotherapy increases RISPC risk. Clinical evidence concerning risk following modern techniques is too immature to draw firm conclusions. The final study demonstrated that SABR techniques resulted in lower estimated RISPC risks in all organs compared to conventionally fractionated techniques, while FFF techniques reduced RISPC risks in out-of-field organs. Conclusions: Linear accelerator-based prostate SABR delivered with a single partial arc is optimal and high levels of TCP and low levels of NTCP are predicted from whole prostate SABR. FFF allows faster treatment delivery. Second malignancy risk is lower using SABR, particularly with FFF, compared to conventionally fractionated techniques. Phase III trials are required to investigate prostate SABR in practice.
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Elder, Eric Scott. "A method and treatment device for non-coplanar radiotherapy of the pancreas." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17656.
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Olausson, Kristina. "Patient experiences of the radiotherapy process and treatment." Doctoral thesis, Umeå universitet, Onkologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-127456.
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Background Most cancer patients undergo external radiotherapy (RT) at some stage during their treatment trajectory. RT is often associated with unfamiliar procedures where the technical environment, side effects and interaction with staff seem to play a major role in the patient’s treatment experience. These experiences could sometimes lead to disruption of the treatment which may have negative consequences for the outcome. The overall aim of this thesis was to gain further knowledge about how patients experience RT and the related processes. Such knowledge is of vital importance when developing and improving care within a high-tech RT environment. Aim The overall aim of this thesis was to gain further knowledge about how patients experience RT and the related processes. Such knowledge is of vital importance when developing and improving care within a high-tech RT environment. Methods To gain further knowledge and understanding about patients experience of RT both quantitative (I, II, III) and qualitative (III, IV) methodology were used. The data in the thesis focused on patients undergoing external RT at different RT units in Sweden. Study I and II, focused on two regions, the northern region of Sweden and the region of Stockholm and Gotland. Study III and IV were performed at eight different RT units in Sweden. Results In Study I, two types of topical agents (Calendula Weleda cream vs. Essex cream) were compared regarding reducing the risk of severe acute radiation skin reactions (ARSR). No difference in severe ARSR was found between the groups and the patients reported low levels of ARSR. In Study II, the influence of an RT unit’s psychosocial climate and treatment environment on cancer patients’ anxiety during external RT was evaluated. Data was collected (questionnaire) from 892 patients. The results showed that both the treatment environment and the psychosocial climate of the RT unit significantly impacted cancer patient anxiety levels. In Study III & IV, a questionnaire to measure the patient´s experience during external RT was developed and tested. The results showed that the RT Experience Questionnaire (RTEQ), with 23 items, was a tentatively valid and reliable instrument to measure how patients experience the RT process and the environment in the treatment room. In Study IV, written comments from the open-ended question “Is there anything else you want us to know?” in the preliminary RTEQ was analysed with qualitative content analysis. This data was abstracted into the following four major categories reflecting the experience of the RT process: Experiences in the high tech RT environment; Understanding the RT procedures and side effects; Dealing with daily life during RT and The nurses’ role and performance. Conclusion The RT environment and the RT related processes seem to impact cancer patients, both physically and psychologically. A person-centered care approach, as well as attention to the design, both of the treatment process and the physical environment could significantly improve the patient experience and patient involvement. The results also highlight the importance of taking patient experiences into account when introducing new RT methods and techniques.
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Tse, Ka-ho, and 謝家豪. "A comparison of contralateral breast dose from primary breast radiotherapy using different treatment techniques." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206498.
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Breast cancer is the most common cancer among women worldwide. Millions of new breast cancer cases are diagnosed every year, accounting for one-tenth of all new cancer cases. Because of the proof of equivalent efficacy between breast-conserving therapy (BCT) plus radiotherapy and mastectomy, increasing number of patients received breast irradiation during the past three decades, and radiotherapy plays a more and more important role in managing breast cancer. With the advancement of technology, the radiotherapy treatment techniques changed from conventional wedged technique to intensity modulated radiotherapy (IMRT), resulting in an improvement in the dose homogeneity. Regardless of the treatment techniques, peripheral dose to the contralateral breast is inevitable. The possibility of the peripheral dose causing contralateral breast cancer (CBC) has re-attracted the interest. However, the variation of the peripheral dose with different treatment techniques has not been well identified. Thus this study aims to compare the contralateral breast dose from the primary breast irradiation using various radiotherapy treatment techniques and types of shielding.
Six treatment plans by different treatment techniques, including paired physical wedges (PW-P), a lateral physical wedge only(PW-L), paired enhanced dynamic wedges (EDW-P), a lateral enhanced dynamic wedge only(EDW-L), field-in-field tangential opposing (TO-FiF), and inverse-planned intensity modulated radiotherapy (IMRT-IP), were generated using a female Rando phantom. The phantom was treated by all plans, and 15 metal oxide semiconductor field effect transistor(MOSFET)detectors on the surface and inside the contralateral breast were utilized for measuring the contralateral breast dose for each plan. Measurement was repeated with the application of 0.2, 0.3 and 0.5cm lead sheets or 0.5 and 1cm superflab (SF) on the TO-FiF to demonstrate the effect of shielding on the contralateral breast dose.
The measured contralateral breast doses were: 2.05Gy for PW-P, 1.44Gyfor PW-L, 1.51Gyfor EDW-P, 1.52Gyfor EDW-L, 1.25Gyfor TO-FiF, and 1.17Gyfor IMRT-IP, corresponding to 2.35% to 4.11% of total dose. PW-P producedthe highest contralateral breast dose while IMRT-IP producedthe lowest. For the addition of shielding, the doses were: 1.25Gy for no shielding, 0.65Gy for 0.2cm lead, 0.61Gy for 0.3cm lead, 0.49Gy for 0.5cm lead, 0.76Gy for 0.5cm SF, and 0.72Gy for 1cm SF. Lead sheet with 0.5cm thickness most effectively reduced the contralateral breast dose by 60%.All techniques showed that the surface dose was much higher than the dose at depth, and the dose dropped exponentially from the surface to the internal. Low energy radiation constitutes a large portion of the contralateral breast dose, so all types of shielding could decrease the surface dose effectively, but not the internal dose. The radiation-induced CBC risks were estimated to be about 0.77% to 1.36%.
To conclude, it is important that the contralateral breast dose to patients, especially those under 45, is maintained minimal. Therefore, TO-FiF or IMRT-IP are recommended to be the treatment of choices. The used of shielding, either lead or SF, is also advisable.published_or_final_version
Diagnostic Radiology
Master
Master of Medical Sciences
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Wu, Wing-cheung Vincent, and 胡永祥. "Dose analysis of 2-dimensional and 3-dimensional radiotherapy techniques in the treatment of nasopharyngeal carcinoma." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B31220149.
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胡寶文 and Po-man Wu. "The application of the tumor control probability model of nasopharyngeal carcinoma in three dimensional conformal treatment planevaluation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31241232.
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Jagannathan, Rupa. "A case-based reasoning system for radiotherapy treatment planning for brain cancer." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/29318/.
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In this thesis, a novel case-based reasoning (CBR) approach to radiotherapy treatment planning for brain cancer patients is presented. In radiotherapy, tumour cells are destroyed using ionizing radiation. For each patient, a treatment plan is generated that describes how the radiation should be applied in order to deliver a tumouricidal radiation dose while avoiding irradiation of healthy tissue and organs at risk in the vicinity of the tumour. The traditional, manual trial and error approach is a time-consuming process that depends on the experience and intuitive knowledge of medical physicists. CBR is an artificial intelligence methodology, which attempts to solve new problems based on the solutions of previously solved similar problems. In this research work, CBR is used to generate the parameters of a treatment plan by capturing the subjective and intuitive knowledge of expert medical physicists stored intrinsically in the treatment plans of similar patients treated in the past. This work focusses on the retrieval stage of the CBR system, in which given a new patient case, the most similar case in the archived case base is retrieved along with its treatment plan. A number of research issues that arise from using CBR for radiotherapy treatment planning for brain cancer are addressed. Different approaches to similarity calculation between cases are investigated and compared, in particular, the weighted nearest neighbour similarity measure and a novel non-linear, fuzzy similarity measure designed for our CBR system. A local case attribute weighting scheme has been developed that uses rules to assign attribute weights based on the values of the attributes in the new case and is compared to global attribute weighting, where the attribute weights remain constant for all target cases. A multi-phase case retrieval approach is introduced in which each phase considers one part of the solution. In addition, a framework developed for the imputation of missing values in the case base is described. The research was carried out in collaboration with medical physicists at the Nottingham University Hospitals NHS Trust, City Hospital Campus, UK. The performance of the developed methodologies was tested using brain cancer patient cases obtained from the City Hospital. The results obtained show that the success rate of the retrieval mechanism provides a good starting point for adaptation, the next phase in development for the CBR system. The developed automated CBR system will assist medical physicists in quickly generating treatment plans and can also serve as a teaching and training aid for junior, inexperienced medical physicists. In addition, the developed methods are generic in nature and can be adapted to be used in other CBR or intelligent decision support systems for other complex, real world, problem domains that highly depend on subjective and intuitive knowledge.
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Mackenzie, Christine. "Emotional functioning of patients before, during and after radiotherapy treatment for cancer." Thesis, Middlesex University, 2003. http://eprints.mdx.ac.uk/13386/.
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Della, Gala Giuseppe. "A method for automated generation of radiotherapy treatment plans for lung cancer." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9549/.
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La radioterapia è una tecnica molto impiegata per la cura del cancro. Attualmente la somministrazione avviene principalmente attraverso la intensity modulated radiotherapy (IMRT, sovrapposizione di campi ad intensità modulata), un cui sviluppo recente è la volumetric modulated arc therapy (VMAT, irradiazione continua lungo un arco ininterrotto). La generazione di piani richiede esperienza ed abilità: un dosimetrista seleziona cost functions ed obiettivi ed un TPS ottimizza la disposizione dei segmenti ad intensità modulata. Se il medico giudica il risultato non soddisfacente, il processo riparte da capo (trial-and-error). Una alternativa è la generazione automatica di piani. Erasmus-iCycle, software prodotto presso ErasmusMC (Rotterdam, The Netherlands), è un algoritmo di ottimizzazione multicriteriale di piani radioterapici per ottimizzazione di intensità basato su una wish list. L'output consiste di piani Pareto-ottimali ad intensità modulata. La generazione automatica garantisce maggiore coerenza e qualità più elevata con tempi di lavoro ridotti. Nello studio, una procedura di generazione automatica di piani con modalità VMAT è stata sviluppata e valutata per carcinoma polmonare. Una wish list è stata generata attraverso una procedura iterativa su un gruppo ristretto di pazienti con la collaborazione di fisici medici ed oncologi e poi validata su un gruppo più ampio di pazienti. Nella grande maggioranza dei casi, i piani automatici sono stati giudicati dagli oncologi migliori rispetto ai rispettivi piani IMRT clinici generati manualmente. Solo in pochi casi una rapida calibrazione manuale specifica per il paziente si è resa necessaria per soddisfare tutti i requisiti clinici. Per un sottogruppo di pazienti si è mostrato che la qualità dei piani VMAT automatici era equivalente o superiore rispetto ai piani VMAT generati manualmente da un dosimetrista esperto. Complessivamente, si è dimostrata la possibilità di generare piani radioterapici VMAT ad alta qualità automaticamente, con interazione umana minima. L'introduzione clinica della procedura automatica presso ErasmusMC è iniziata (ottobre 2015).
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Wilson, Elena McNaught. "Three dimensional conformal radiotherapy treatment planning for non-small cell lung cancer." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404897.
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Eardley, A. "The care of urological cancer patients : Delay in obtaining treatment and problems following radiotherapy." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234189.
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Neal, Anthony James. "Optimisation of radiotherapy treatment planning for tumours of the breast, prostate and brain." Thesis, King's College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306922.
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Johansson, Jonas. "Comparative Treatment Planning in Radiotherapy and Clinical Impact of Proton Relative Biological Effectiveness." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6593.
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Orvehed, Hiltunen Erik. "Robust optimization of radiotherapy treatment plans considering time structures of the delivery." Thesis, Uppsala universitet, Avdelningen för datalogi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355628.
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Cancer is the second largest mortal disease in Sweden, and high efforts are made to develop the treatment of cancer. One of the main treatment methods is radiotherapy, which uses ionizing radiation to damage the cancerous cells. This has the chance of stopping the cell reproduction, and the goal is to reduce the tumor and stop the tumor growth. The most common forms of radiotherapy uses external beams to irradiate the tumor. In intensity modulated radiotherapy, IMRT, the beam fluences are optimized to give a highly conformal dose, i.e. a dose distribution which is restricted to the tumor and has low dose values outside of the tumor. A conformal dose is necessary to spare healthy tissue and sensitive organs, and thus keep the side-effects of the treatment at an acceptable level. The optimized beam shapes are created using a multileaf collimator, MLC. Finding the leaf positions and dose levels is formulated as a problem in the framework of mathematical optimization. Currently, one of the limitations in delivering conformal dose is due to patient movement during the treatment. In IMRT, the beams are delivered by consecutive segments, and the exact pairing of the segments with the patient position will have an impact on the delivered dose. This is called the interplay effect, and can cause both underdosage of the tumor and overdosage of the surrounding tissue. There are methods of mitigating the interplay effect. For example, the beam could be restricted to a single phase of the motion by repeatedly turning it on and off. This is known as gating. However, gating and many other interplay mitigation techniques lead to prolonged treatment times, which decreases the clinical throughput, causes higher patient discomfort and gives higher uncertainties in the delivered dose. This makes it desirable to find methods which avoid prolonged treatment times, while still giving highly conformal doses. Ideally, the best method would be to have a beam which follows any target movement. This idea is known as target tracking. In this thesis, an optimization method is suggested which includes the interplay effect in the treatment optimization. Two main treatment strategies are proposed. The method which is simplest to implement clinically is to create plans which are robust against uncertainties in the times for the patient motion. The resulting doses are found to give acceptable target covering where similar, conventional plans give a significant target underdose. To further increase the conformality of the doses, a non-robust method paired with gating technology is suggested. This method can effectively be seen as a target tracking method, and has the possibility to give highly conformal doses under acceptable treatment times.
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Brock, Juliet. "Advanced technology of radiotherapy in the treatment of non-small cell lung cancer." Thesis, Institute of Cancer Research (University Of London), 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538697.
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Lilley, Francis. "An optical 3D body surface measurement system to improve radiotherapy treatment of cancer." Thesis, Liverpool John Moores University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313092.
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Delaney, Geoffrey Paul SWSAHS Clinical School UNSW. "The Development of a New Measure of Linear Accelerator Throughput in Radiation Oncology Treatment Delivery - The Basic Treatment Equivalent (B.T.E.)." Awarded by:University of New South Wales. SWSAHS Clinical School, 2001. http://handle.unsw.edu.au/1959.4/33381.
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The measurement of productivity in health care is difficult. Studies in various specialty disciplines of medicine have identified that the variation in complexities (casemix) between departments or hospitals will vary and therefore will affect any basic productivity statistics that are produced. Radiation oncology is a discipline of medicine where no such studies into radiotherapy casemix variations and the effect that these may have on productivity measures have been performed, despite the high capital expenditure involved in the delivery of radiotherapy. Radiation oncology productivity on linear accelerators is currently measured by the number of patients treated or number of treatment fields treated per unit time (usually per hour). These statistics have been collected for many years and productivity assessments were made on the variations in these statistics that exist between departments. However, these statistics do not consider the variations in casemix that occur between departments. These complexity differences may be quite marked and therefore may strongly influence the ability of a department to achieve a high patient or treatment field throughput. This may be seen as 'reduced productivity' with no consideration of the complexity of the caseload seen in the department. In addition, future technological changes that improve patient outcome may be introduced. These changes may make treatment more complex. Using older measures of productivity such as fields per hour or patients per hour will not consider these technological changes and the subsequent changes in complexity and hence departments may be seen as less productive in the future using current methods of analysis unless a more valid measure of productivity that considers complexity variations is introduced. There have only been 3 previous attempts at developing measures of linear accelerator productivity. Each of these models have been developed empirically and have not been clinically validated. No previous attempts have been made in determining a scientifically-derived complexity model that considers the variations in treatment technique. This thesis describes research performed between 1995 and 2001. This research study???s primary aims were to study the factors that affect radiotherapy treatment time and treatment complexity and to develop a model of linear accelerator productivity that does consider complexity variations in radiotherapy treatment delivery. This model is called the Basic Treatment Equivalent (B.T.E.). This series of trials examines the old models of linear accelerator productivity, describes the derivation and validation of the BTE model both in Australasia and the United Kingdom, identifies the factors that contribute to treatment time and treatment complexity, describes the development of a pilot model of productivity of gynaecological brachytherapy and outpatient chemotherapy using similar BTE methodology, discusses the potential uses of the BTE model, recent independent reviews of BTE by other groups, and the advantages and disadvantages of using such a model. This research has shown that it is possible to identify the various factors that contribute to treatment time and treatment complexity and to derive a model of linear accelerator productivity that considers the variations in complexity. The BTE model has been clinically validated in Australia, New Zealand and a couple of departments in the United Kingdom and Canada and has been adopted as a new measure by various groups. It requires regular updating to maintain currency particularly as there are frequent improvements in radiation treatment technology. Future studies should identify the differences these technological enhancements make to productivity. The BTE derived from outpatient chemotherapy delivery and gynaecological brachytherapy delivery shows promise although these models require further research with the assistance of other departments.
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Bailie, Karen E. M. "Quality in clinical decision making : the treatment of breast cancer in Northern Ireland." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343063.
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Fridriksson, Jon Örn. "Adverse effects of curative treatment of prostate cancer." Doctoral thesis, Umeå universitet, Urologi och andrologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-128709.
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Background Screening for prostate cancer is debated, there is conflicting data on the net benefit of screening. Men who consider screening need to be informed on the pros and cons. Rehospitalization after surgery can be used as an indicator of general quality of care. For radical prostatectomy, little is known on the readmission rate after surgery. Men diagnosed with low- and intermediate-risk prostate cancer have low prostate-cancer specific mortality. However, adverse effects after curative treatment can be severe and decrease quality of life. Curative treatments for prostate cancer differ mainly in the pattern of adverse effects but detailed analysis of long-term adverse effects is lacking. The aim of this thesis was to assess the perioperative quality of radical prostatectomy and the risk of adverse effects after curative treatment for prostate cancer. Material and Methods In this thesis, data from the National Prostate Cancer Register (NPCR) and other nationwide Swedish registers were used. By use of the Swedish personal identity number, NPCR was cross-linked to other registers creating Prostate Cancer data Base Sweden (PCBaSe), a large dataset for research. Results The proportion of men who had received information on the pros and cons of screening for prostate cancer with PSA testing was low (14%) indicating that the majority of men who were screened did not make an informed decision. The risk of rehospitalization within 90 days after radical prostatectomy was approximately 10% and similar after retropubic and robot-assisted radical prostatectomy. Compared to controls, there was an increased risk of adverse effects after both radiotherapy and radical prostatectomy up to twelve years after treatment and the overall risk was quite similar after retropubic and robot-assisted radical prostatectomy. Conclusion Improved information to men on the pros and cons of PSA screening is warranted. The risk of adverse effects was elevated up to 12 years after curative treatment for prostate cancer. The pattern of adverse effects was different after radiotherapy and radical prostatectomy but quite similar after retropubic and robot-assisted radical prostatectomy.
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Uitterhoeve, Apollonia Léonie Joséphine. "Radiotherapy and Cisplatin: outcome of combined modality treatment in non-small cell lung cancer." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/47061.
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Pijls-Johannesma, Madelon. "Optimization of radiotherapy in lung cancer treatment balance between survival and quality of life /." Maastricht : Maastricht : Universitaire Pers ; University Library, Universiteit Maastricht [host], 2008. http://arno.unimaas.nl/show.cgi?fid=13773.
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Christian, Judith Ann. "Evaluation of new techniques in the radiotherapy treatment of non-small cell lung cancer." Thesis, Institute of Cancer Research (University Of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411594.
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Lee, W. M. Anne, and 李詠梅. "Therapeutic benefits of concurrent chemoradiotherapy for advanced nasopharyngeal carcinoma." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41290677.
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Barton, Michael Clinical School South Western Sydney Faculty of Medicine UNSW. "The improvement of cancer management by the application of the currently available knowledge." Awarded by:University of New South Wales, 2008. http://handle.unsw.edu.au/1959.4/39210.
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I have been intensively involved in the research on the application of currently available knowledge for the improvement of cancer care. This research covers the types of treatment that are appropriate for different clinical conditions (benchmarking and guidelines), planning services to improve access for patients, monitoring service delivery through patterns of care studies and development of the knowledge and skills of the cancer workforce. I devoted considerable effort to better educating the cancer workforce by measuring cancer teaching and developing model curricula and innovative teaching programs. I have made substantial contributions to knowledge about best practice by developing clinical practice guidelines and have developed tools and plans for cancer service delivery and have had a major influence on the training of the undergraduate and specialist medical workforce about cancer.
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Stewart, Grant Duncan. "Novel survival factors and approaches to the treatment of hypoxic prostate cancer." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/4390.
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Tumour hypoxia has been demonstrated to cause development of an aggressive tumour phenotype and is associated with increased patient mortality and poorer response to treatments such as chemotherapy and radiotherapy. Previous studies have established that hypoxia exists within a nidus of prostate cancer. Based on the importance of the tumour microenvironment, especially hypoxia, in prostate cancer, the major aims of this thesis were to establish: (a) the role of a novel putative survival factor, dermcidin, in prostate cancer survival under hypoxia/oxidative stress; and (b) the effect of nitric oxide-donating non-steroidal anti-inflammatory drugs (NO-NSAIDS), a new class of drugs, on the killing of prostate cancer cells subjected to hypoxia. A wide-range of confirmatory, cellular and molecular biology techniques were employed in this thesis. The PC-3 hormone-insensitive prostate cancer cell line was used for the majority of studies as this cell line represents hormone-independent prostate cancer, treatment of which is currently palliative. Cell incubation at 0.2% oxygen for 48 hours was established as suitable conditions to stimulate the development of the hypoxia response. Upregulation of nuclear hypoxia-inducible factor-1α protein was the main marker used to assess the hypoxia response. Dermcidin messenger RNA production was found to occur in a range of prostate cancer cell lines; was upregulated in cell lines by both hypoxic and oxidative stress; and found to act as a proliferation, survival and pro-invasion factor under hypoxia and oxidative stress in immortalised prostate cancer cell lines. Furthermore, the portion of the dermcidin molecule responsible for the survival advantage was localised to the proteolysis-inducing factor core peptide subunit. However, subsequent analysis of primary cancer samples from prostate cancer patients revealed that dermcidin was not expressed in these tumours, although dermcidin mRNA was identified in analysis of other primary tumours. As such, the role of dermcidin in prostate cancer was not evaluated further in this thesis. Investigation of NO-sulindac (a NO-NSAID drug) in hypoxic PC-3 cells showed that these agents were significantly more pro-necrotic, pro-apoptotic and anti-invasive than traditional, unnitrated sulindac. NO-sulindac was found to downregulate the hypoxia response mounted by PC-3 cells under hypoxia via the Akt signalling pathway. Finally, analysis of the role of NO-sulindac in radiosensitising hypoxic PC-3 cells showed that NO-sulindac caused significant radiosensitisation under normoxia, but particularly in hypoxic conditions. As such, NO-NSAIDs show great promise as neoadjuvant, concurrent and adjuvant treatments for patients with hypoxic prostate cancer. The findings of this thesis illustrate several potential novel strategies for treatment of hormone-independent prostate cancer.
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Owusu, Miriam Sekyere. "Lymphedema, post breast cancer treatment at Komfo Anokye Teaching Hospital, Kumasi, Ghana." Thesis, Cape Peninsula University of Technology, 2011. http://hdl.handle.net/20.500.11838/2262.
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Thesis (MTech (Nursing))--Cape Peninsula University of Technology, 2011.To determine the incidence, risk factors and the treatment of lymphedema after breast cancer treatment at the oncology unit of KATH, Kumasi, Ghana from 01 January 2005 to 31 December 2008. Descriptive retrospective survey was used. Using a data capture sheet, data was collected from the medical records of the breast cancer patients. Breast cancer and lymphedema-related variables were collected. Data was analyzed as descriptive statistics. Chi-square test was applied to determine whether or not two variables are independent variables. Among 313 patients treated for breast cancer between 2005 and 2008, 31 (9.9%) developed lymphedema after treatment. A chi-square test showed that axillary lymph node dissection was statistically a significant risk factor of lymphedema (Chi-square test value=7.055, P value=0.008). Radiation and late stage of breast cancer diagnosis may have contributed in development of lymphedema despite having P value> 0.05. Age, body mass index (BMI) and hypertension were also not associated with lymphedema.
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Knight, Kellie Ann. "Daily Image Guided Radiation Therapy for Prostate Cancer: An assessment of treatment plan reproducibility." University of Sydney, 2006. http://hdl.handle.net/2123/1628.
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Doctor of Health ScienceIt is well documented that for prostate cancer patients undergoing radiation therapy there is a correlation between target volume displacement and changes in bladder and rectal volumes. However, these studies have used a methodology that has captured only a subset of all treatment positions. This research used daily Computer Tomography (CT) imaging to comprehensively assess organ volumes, organ motion and their effect on dose, something that has never been performed previously, thus adding considerably to the understanding of the topic. Daily CT images were obtained using a Siemens Primus Linear Accelerator equipped with an in-room Somatom CT unit in the accelerator suite, marketed as ‘Primatom’, to accurately position the patient prior to treatment delivery. The internal structures of interest were contoured on the planning workstation by the investigator. The daily volume and location of the organs were derived from the computer to assess and analyse internal organ motion. The planned dose distribution was then imported onto the treatment CT datasets and used to compare the planned dose to i) the actual isocentre, where the isocentre was actually placed for that fraction, ii) the uncorrected isocentre, by un-doing any on-line corrections performed by the treatment staff prior to treatment delivery, and iii) the future isocentre, by placing the isocentre relative to internal organ motion on a daily basis. The results of this study did not confirm a statistically significant decrease in rectum volumes over time (hypothesis 1), however large fluctuations in bladder volume were confirmed (hypothesis 2). Internal organ motion for the rectum and bladder was demonstrated to be related to organ filling. Ideal planning volumes for these organs have been reported to minimise systematic and random uncertainty in the treatment volumes. An observed decrease in prostate volume over time, a systematic uncertainty in the location of the prostate at the time of the planning CT scan and a significant relationship between prostate centre of volume and rectum and bladder volumes has resulted in a recommendation that patients should be re-scanned during treatment to ensure appropriate clinical target volume coverage. A significant relationship between rectal and bladder volumes and the dose delivered to these organs was found (hypothesis 3). The dose delivered to the planning target volume was not related to the rectal or bladder volumes, although it was related to the motion of these organs. Despite these results only minimal effects on the dose delivered to any of the three isocentres occurred, indicating that the planned dose was accurately delivered using the methodology presented here (hypothesis 4). However the results do indicate that the patient preparation instructions need to be improved if margins are to be reduced in the future. It is unrealistic to assume that Image Guided Radiation Therapy will ever become routine practice due to infrastructure costs and time limitations. This research will inform radiation therapy centres of the variables associated with prostate cancer treatment on a daily basis, something that has never before been realistically achievable. As a result centres will be able to devise protocols to improve treatment outcomes.
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Wirth, Manfred P., and Michael Fröhner. "Perspectives in Adjuvant Treatment of Prostate Cancer." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133839.
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McGowan, Stacey Elizabeth. "Incorporating range uncertainty into proton therapy treatment planning." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/248787.
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This dissertation addresses the issue of robustness in proton therapy treatment planning for cancer treatment. Proton therapy is considered to be advantageous in treating most childhood cancers and certain adult cancers, including those of the skull base, spine and head and neck. Protons, unlike X-rays, have a finite range highly dependent on the electron density of the material they are traversing, resulting in a steep dose gradient at the distal edge of the Bragg peak. These characteristics, together with advancements in computation and technology have led to the ability to plan and deliver treatments with greater conformality, sparing normal tissue and organs at risk. Radiotherapy treatment plans aim to meet set dosimetric constraints, and meet them at every fraction. Plan robustness is a measure of deviation between the delivered dose distribution and the planned dose distribution. Due to the same characteristics that make protons advantageous, conventional means of using margins to create a Planning Target Volume (PTV) to ensure plan robustness are inadequate. Additional to this, without a PTV, a new method of analysing plan quality is required in proton therapy. My original contribution to the knowledge in this area is the demonstration of how site- and centre- specific robustness constraints can be established. Robustness constraints can be used both for proton plan analysis and to identify patients that require plans of greater individualisation. I have also used the daily volumetric imaging from patients previously treated with conventional radiotherapy to quantify range uncertainty from inter- and intra-fraction motion. These new methods of both quantifying and analysing the change in proton range in the patient can aid in the choice of beam directions, provide input into a multi- criteria optimisation algorithm or can be used as criteria to determine when adaptive planning may be required. This greater understanding in range uncertainty better informs the planner on how best to balance the trade-off between plan conformality and robustness in proton therapy. This research is directly relevant to furthering the knowledge base in light of HM Government pledging £250 million to build two proton centres in England, to treat NHS patients from 2018. Use of methods described in this dissertation will aid in the establishment of clear and pre-defined protocols for treating patients in the future.
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Ayles, Michael. "Minimizing errors in treatment planning and delivery during external beam radiotherapy for lung cancer patients." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40731.
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In this thesis, a two-part investigation was conducted to determine methods of reducing the inaccuracy in the treatment of solid tumors in the lung. In the first part, a visual feedback system was investigated for use during respiratory gating procedures, both during simulation and treatment. The visual feedback system was installed in the clinic and was used by three patients during radiotherapy and by approximately 15 patients during simulation. The use of the visual feedback was found to increase the regularity of the patients’ breathing patterns and improved the ability of the gating technique to compensate for internal tumor motion. The second part consisted of a comparison of the dose distribution algorithms of the Eclipse treatment planning system with dose calculations performed using Monte Carlo methods based on the EGSnrc and DOSXYZnrc user codes for BEAMnrc. Four patients with lung tumors, whose treatment plans called for small, 18 MV photon fields, were recalculated using both systems. Results showed that the algorithms used by the TPS consistently overestimated the dose in the lung, due to the lack of lateral electron equilibrium in the lung tissue.Dans ce mémoire, une enquête en deux parties à été entreprise pour analyser des méthodes permettant la réduction d’erreurs dans le traitement des cancers pulmonaires. Dans la première partie de l’enquête, nous analysons un système de « feedback » visuel utilisé avec les procédures de « gating » en simulation et en radiothérapie. Ce système a été installé dans la clinique et utilisé par trois patients pendant la radiothérapie et une quinzaine de patients pendant des simulations CTs. Il a ainsi été observé que l’utilisation du « feedback » permettait de régulariser la respiration des patients et ainsi d’optimiser l’utilisation des techniques de « gating » afin de réduire l’effet des mouvements interne des tumeurs durant la thérapie et les simulations. La deuxième partie de l’enquête consistait en une étude retrospective qui avait pour but de permettre la comparaison de plusieurs algorithmes de calcul de dose. Les résultats obtenus à l’aide des algorithmes du système de planification de traitements Eclipse ont été comparés à ceux qui ont été calculés en utilisant les codes Monte Carlos EGSnrc et DOSXYZnrc. Les données de quatre patients souffrant du cancer du poumon qui avaient étés traités avec des faisceaux de photons 18 MV ont ainsi été recalculées. Les résultats obtenus ont démontré que les algorithmes d’Eclipse surestimaient systématiquement les doses à cause de la faible densité des tissus pulmonaires et du manque d’équilibre électronique dû au dimensions des faisceaux.
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Ryalat, Mohammad. "Automatic construction of immobilisation masks for use in radiotherapy treatment of head-and-neck cancer." Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/66573/.
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Current clinical practice for immobilisation for patients undergoing brain or head and neck radiotherapy is normally achieved using Perspex or thermoplastic shells that are moulded to patient anatomy during a visit to the mould room. The shells are “made to measure” and the methods currently employed to make them require patients to visit the mould room. The mould room visit can be depressing and some patients find this process particularly unpleasant. In some cases, as treatment progresses, the tumour may shrink and therefore there may be a need for a further mould room visits. With modern manufacturing and rapid prototyping comes the possibility of determining the shape of the shells from the CT-scan of the patient directly, alleviating the need for making physical moulds from the patients’ head. However, extracting such a surface model remains a challenge and is the focus of this thesis. The aim of the work in this thesis is to develop an automatic pipeline capable of creating physical models of immobilisation shells directly from CT scans. The work includes an investigation of a number of image segmentation techniques to segment the skin/air interface from CT images. To enable the developed pipeline to be quantitatively evaluated we compared the 3D model generated from the CT data to ground truth obtained by 3D laser scans of masks produced by the mould room in the frame of a clinical trial. This involved automatically removing image artefacts due to fixations from CT imagery, automatic alignment (registration) between two meshes, measuring the degree of similarity between two 3D volumes, and automatic approach to evaluate the accuracy of segmentation. This thesis has raised and addressed many challenges within this pipeline. We have examined and evaluated each stage of the pipeline separately. The outcomes of the pipeline as a whole are currently being evaluated by a clinical trial (IRAS ID:209119, REC Ref.:16/YH/0485). Early results from the trial indicate that the approach is viable.
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Nakamura, Akira. "Analysis of Dose Intensification for the Improvement of Treatment Outcomes of Radiotherapy for Pancreatic Cancer." Kyoto University, 2013. http://hdl.handle.net/2433/174808.
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Wirth, Manfred P., and Michael Fröhner. "Perspectives in Adjuvant Treatment of Prostate Cancer." Karger, 2002. https://tud.qucosa.de/id/qucosa%3A27540.
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Wirth, Manfred P., and Michael Fröhner. "Adjuvant Hormonal Treatment for Prostate Cancer: The Bicalutamide Early Prostate Cancer Program." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133551.
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Adjuvant hormonal therapy has been demonstrated to be able to delay disease progression in nonmetastatic prostate cancer. To date, however, a favorable impact on survival has only been demonstrated in lymph-node-positive disease and in external-beam radiotherapy series with locally advanced and probably mainly micrometastatic tumors. The Bicalutamide Early Prostate Cancer Program is the largest study under way to define the role of adjuvant treatment in early prostate cancer and identify subgroups of patients likely to benefit from immediate hormonal therapy. At the time of the most recently published analysis, the risk of objective clinical progression was significantly reduced in the bicalutamide arm (hazards ratio 0.58, 95% confidence interval 0.51–0.66, p < 0.0001). However, further maturation of data is needed to see whether this difference will lead to a survival advantageDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
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Sandberg, Linnea. "Quality assurance of a radiotherapy registry." Thesis, Umeå universitet, Institutionen för fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-176779.
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The radiotherapy clinics in Sweden have been without a functioning national platform consisting of dose data from patients undergoing radiotherapy. A national collaboration between clinics will improve the quality of radiotherapy since clinics will be able to compare dose data from treatment plans between clinics. It will also help and improve future researches in radiotherapy. A new national quality registry for radiotherapy in Sweden is under development and is located on the INCA platform. The aim of this study is to do a quality assurance of the INCA registry. The data stored in the registry are calculated from the treatment plans stored locally at the clinics. The quality assurance of the registry is done by creating a program run by Python code and by using Streamlit as the graphical user interface. The program takes dose and volume data from the dose volume histograms located in treatment plans from the INCA database and compares it with the dose and volume data from the local clinics' treatment planning system. The different treatment planning systems considered in the program are Oncentra(Elekta, Sweden), Eclipse(Varian, U.S.), RayStation(RaySearch Laboratories, Sweden) and Monaco(Electa, Sweden). The compared absorbed doses are the dose to 99% of the structure volume(D99%), D98%, D50%, D2% and D1%. The program generates how much the INCA data differs from the TPS data in percent and is named QARS(Quality Assurance of the Radiotherapy Database in Sweden). A verification of the created program and a preliminary evaluation is done on a limited dataset containing three patient groups(prostate patients, lung patients and head and neck patients) with five patients in each group. The dataset is run through the program with patient data from both Oncentra and Eclipse. The result indicates that all the near-maximum doses, D2% and D1% in INCA are very close to their corresponding TPS dose. There is a more noticeable difference in the near-minimum doses, D99% and D98% but also for some D50% where the difference seems to increase in larger structure volumes with very low doses and in very small structure volumes, smaller than 0.01 cm3. It is compared how well INCA agrees with Oncentra and Eclipse respectively and it is clear that Eclipse has a smaller difference to INCA than Oncentra for structures with very small volumes and larger structures with low doses. To summarise the study, it generates a program for quality assurance of the national quality registry for radiotherapy in Sweden which hopefully can help improve the quality of radiotherapy and help future researches in the field.
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Wirth, Manfred P., and Michael Fröhner. "Adjuvant Hormonal Treatment for Prostate Cancer: The Bicalutamide Early Prostate Cancer Program." Karger, 2003. https://tud.qucosa.de/id/qucosa%3A27515.
Full textAbstract:
Adjuvant hormonal therapy has been demonstrated to be able to delay disease progression in nonmetastatic prostate cancer. To date, however, a favorable impact on survival has only been demonstrated in lymph-node-positive disease and in external-beam radiotherapy series with locally advanced and probably mainly micrometastatic tumors. The Bicalutamide Early Prostate Cancer Program is the largest study under way to define the role of adjuvant treatment in early prostate cancer and identify subgroups of patients likely to benefit from immediate hormonal therapy. At the time of the most recently published analysis, the risk of objective clinical progression was significantly reduced in the bicalutamide arm (hazards ratio 0.58, 95% confidence interval 0.51–0.66, p < 0.0001). However, further maturation of data is needed to see whether this difference will lead to a survival advantage.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
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suh, yelin. "DEVELOPMENT AND INVESTIGATION OF INTENSITY-MODULATED RADIATION THERAPY TREATMENT PLANNING FOR FOUR-DIMENSIONAL ANATOMY." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1827.
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Lung cancer is the leading cause of cancer-related deaths worldwide. Radiotherapy is one of the main treatment modalities of lung cancer. However, the achievable accuracy of radiotherapy treatment is limited for lung-based tumors due to respiratory motion. Four-dimensional radiotherapy explicitly accounts for anatomic motion by characterizing the motion, creating a treatment plan that accounts for this motion, and delivering this plan to the moving anatomy. This thesis focuses on the current problems and solutions throughout the course of four-dimensional radiotherapy. For characterization of respiratory-induced motion, patient tumor motion data were analyzed. It is shown that tumor motion can be significant during radiotherapy treatment, and its extent, direction, and linearity vary considerably between patients, between treatment fractions, and between respiratory cycles. After this, approaches to four-dimensional intensity-modulated radiation therapy treatment planning were developed and investigated. Among the techniques to manage respiratory motion, tumor tracking using a dynamic multileaf collimator delivery technique was chosen as a promising method. A formalism to solve a general four-dimensional intensity-modulated radiation therapy treatment-planning problem was developed. Specific solutions to this problem accounting for tumor motion initially in one dimension and extending this to three dimensions were developed and investigated using four-dimensional computed tomography planning scans of lung cancer patients. For four-dimensional radiotherapy treatment delivery, accuracy of two-dimensional projection imaging methods was investigated. Geometric uncertainty due to the limitation of two-dimensional imaging in monitoring three-dimensional tumor motion during treatment delivery was quantified. This geometric uncertainty can be used to estimate proper margins when a single two-dimensional projection imager is used for four-dimensional treatment delivery. Lastly, tumor-tracking delivery using a moving average algorithm was investigated as an alternative delivery technique that reduces mechanical motion constraints of a multileaf collimator. Moving average tracking provides an approximate solution that can be immediately implemented for delivery of four-dimensional intensity-modulated radiation therapy treatment. The clinical implementation of four-dimensional guidance, intensity-modulated radiation therapy treatment planning, and dynamic multileaf collimator tracking delivery may have a positive impact on the treatment of lung cancer.
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Kyei, Kofi Adesi. "Assessment of Anxiety and Depression Among Breast Cancer Patients Undergoing Treatment in Ghana." ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/4526.
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Breast cancer patients undergoing radiotherapy often experience severe levels of anxiety and depression. There is a gap in the research literature from Africa, particularly from Ghana, with few studies focusing on the assessment of anxiety and depression among breast cancer patients undergoing radiation treatment. A better understanding was essential to promote efforts to help breast cancer patients cope with their diagnosis and treatment and increase their overall quality of life. This mixed method study examined breast cancer patients in Ghana undergoing radiotherapy and their responses related to anxiety and depression through a concurrent triangulation involving an interview with selected professional participants and a detailed patient survey. Patients completed 2 modified scales, the Patient Health Questionnaire and Depression Anxiety Stress Scale. The sample consisted of 100 patients between the ages of 20-89. Individual interviews were held with 6 professionals with a minimum of 5 years of work experience. Themes were generated through open coding of the interview data, while multiple regression was performed to determine the relationship between depression and anxiety with the independent variables . Findings of this study indicated the need intervene through counseling and education on behalf of patients in Ghana as they undergo breast cancer treatment. Age and monthly income of patients were statistically significant in predicting the anxiety and depression among the patients. The study's implications will lead to positive change when all stakeholders take on the responsibility of implementing measures to promote coping strategies for breast cancer patients in Ghana.
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Svensson, Sara. "Variations in the target definition on CT and MR based treatment plans for radiotherapy." Thesis, Umeå universitet, Centrum för medicinsk teknik och fysik (CMTF), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-96753.
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The introduction of Magnetic Resonance (MR) Imaging in treatment planning for radiotherapy of prostate cancer give rise to new challenges in defining the treatment volume, or the target. Imaging with MR have several advantages, especially better soft-tissue contrast, compared with the standard image modality, Computed Tomography (CT). The purpose of this project was to determine how the target definition varies with the choice of image modality and the systematic differences between them. The purpose was also to determine how the inter- and intra physician variability influences the delineation, depending on which image modality that is used. In the project, five physicians delineated the prostate gland on CT and MR images for nine patients. The physicians had no information of which image series that was connected, and were thus delineating independent. After the delineation, the CT and MR image series was set in the same geometrical coordinate system in the treatment planning system Oncentra. The target delineations were analysed by comparing the radial distances from the centre of mass in different directions, such as anterior, posterior, etc. The radial distances were later used to evaluate the variability of the delineations and to determine the inter and intra physician variability in different directions of the targets. ANOVA was also preformed to determine if there is a significant difference between the parameters, as the image modality and the image modalities influence on the physicians delineations. A model was made to investigate how the MR delineations differ from a CT defined volume that 95% of the delineations cover, called the ideal CT delineation. From this, the median deviation in different directions was analysed and it was found that the median value of the MR delineations in different directions was between -0.10-2.27 mm larger than the ideal CT delineation. The fluctuations between the delineations was, however, large. The target volume was larger for CT defined volumes in 87% of the cases, compared with MR targets. The inter physician variability was found to be between 0.54-2.17 mm for the CT based delineations and 0.68-2.08 mm for the MR based target delineations. The intra physician variability was larger than the inter physician variability, between 0.74-2.51 mm for CT based delineations and 0.85-1.45 mm for MR based delineations. The median variability of the delineations were not uniform around the target volume but were larger for example in the superior and inferior directions and had its minimum in the posterior direction. The ANOVA tests showed a significant difference between MR and CT based target delineations, it also shows a relation between the delineating physician and the image modality, meaning that the physicians are delineating different on CT and MR images. Target volumes defined on MR images are in general smaller than the CT defined targets. The soft tissue contrast in MR images makes the delineating process easier, however, the analysis of the variability in this project indicates that the variations of MR based target delineations are larger than the CT based. The large variation of the delineations implies that clinical tests should be made to ensure a proper dose coverage before MR could be used as the only image modality in radiotherapy treatment planning of prostate cancer.
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De, Armas Ricardo Eduardo. "Impact of intrafractional prostate motion on the accuracy and efficiency of prostate cancer treatment on CyberKnife radiotherapy." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98920.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 39-41).
One of the most common treatments for men with localized prostate cancer is radiation therapy, which involves delivering small doses of radiation to the prostate for an extended period of time. Stereotactic-body radiation therapy (SBRT) is a form of radiotherapy that delivers increased dosage to the prostate with more precision. The results are shorter treatment times, increased effectiveness, and less toxicity to surrounding tissue. However, the prostate has been found to move around during treatment (intrafraction) and between treatments (interfraction). With greater precision, there is a greater risk of missing the target while the prostate is moving. This study assesses the impact of intrafractional prostate motion on the accuracy and efficiency of SBRT on CyberKnife. Prostate tracking log files were acquired from 6 patients with prostate cancer, which comprises18 SBRT fractions and 1,892 X-ray image registrations. Each image contains real-time prostate motion in 6D. The data were compared against clinically used margins to identify periods of large prostate motion during treatment. Results indicate significant periods of prostate motion, with the greatest movement occurring in anterior-posterior translation (6.2% outside margin) and pitch rotation (4.3% outside margin). The percentage of prostate motion beyond margins varied among patients, with an average of 12.8% outside clinical margins and 36.0% outside hypothetically reduced margins. The treatment time for each fraction was also recorded to quantify the efficiency of CyberKnife delivery. Because of motion-related delays, optimal setup of 5-15 minutes was seen in only 50% of the fractions, and optimal beam delivery times of 30-40 minutes in 44% of fractions. Thus, results suggest that treatment accuracy and efficiency were negatively affected by the occurrence of large prostate motion. Techniques that immobilize the prostate during treatment may be considered to reduce intrafractional prostate motion and ensure greater accuracy and efficiency of prostate cancer SBRT.
by Ricardo Eduardo De Armas.
S.B.
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Kishi, Takahiro. "Comparative evaluation of respiratory-gated and ungated FDG-PET for target volume definition in radiotherapy treatment planning for pancreatic cancer." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225447.
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Marcu, Loredana Gabriela. "Deterministic modelling of kinetics and radiobiology of radiation-cisplatin interaction in the treatment of head and neck cancers." Title page, contents and abstract only, 2004. http://hdl.handle.net/2440/37961.
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One of the main objectives of combining radiation treatment and chemotherapy is to obtain a therapeutic gain by an improved tumour control with less or no enhancement of normal tissue toxicity. The optimal schedule for the combined treatment of cisplatin-radiation is still under investigation. Neither the optimal time interval, nor the most adequate sequence of administration of cisplatin and radiation are known. The results of the trials are also inconclusive. Some trials showed a supra-additive effect from the administration of cisplatin before radiotherapy, others, on contrary, from the injection of drug after radiotherapy. The present work encompasses the major challenges brought by the combined modality treatment: cisplatin-radiotherapy. The major goal of this work was to investigate the optimal treatment sequencing between cisplatin and radiotherapy and also the optimal schedule for head and neck carcinomas. Therefore, a computer-based tumour model with literature-given biological parameters has been developed which has allowed the simulation of treatment with radiation and chemotherapy. Radiotherapy has been simulated on the virtual tumour and the effects of radiotherapy on tumour regression and regrowth have been analyzed. Also, the mechanisms of cisplatin's action on tumour have been implemented, and the phenomena of drug resistance and tumour repopulation during chemotherapy studied. Finally, the combined modality treatment has been simulated, and the effect of drug-radiation interaction on tumour behaviour evaluated. The current investigation has shown that cisplatin administered immediately before radiation gives similar tumour control to the post-radiation sequencing of the drug. Furthermore, the killing effect of the combined modality treatment on tumour increases with the increase in cell recruitment. The individual cell kill produced by cisplatin and radiation leads to an additive-only tumour response when the treatments are given concurrently, and for a synergistic effect cisplatin must potentiate the effect of radiation. The final conclusion, by which cisplatin administered on a daily basis leads to a better tumour control than cisplatin administered weekly, is in accordance with the latest trial results on head and neck cancers. Therefore, treatment regimens that correlate better with the pharmacokinetics and the radiobiological properties of the therapeutic agents result in better outcomes.Thesis (Ph.D.)--School of Chemistry and Physics, 2004.
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De, Pomeroy-Legg Jeanita. "Prevalence of side-effects and change in nutritional status during radical radiotherapy for head and neck malignancies at Tygerberg Academic Hospital, Western Cape, South Africa." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1492.
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Filipov, Danielle. "Avaliação da dose fetal em radioterapia de mama, com câmara de ionização cilíndrica, usando blindagem e filtros físico e dinâmico." Universidade Tecnológica Federal do Paraná, 2010. http://repositorio.utfpr.edu.br/jspui/handle/1/1311.
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Quando uma mulher grávida é submetida à radioterapia mamária, o feto pode ser gravemente afetado pela dose periférica. Com o objetivo de verificar essa dose, um objeto simulador humanóide foi irradiado na mama esquerda. O phantom é um manequim adaptado, com alguns materiais (de densidades próximas a da água) dentro e fora do mesmo. A irradiação foi feita usando feixes de raios X de energia de 6 MeV, provenientes de um acelerador linear “Clinac 600C”. Durante as irradiações, foi empregada uma blindagem, constituída de blocos e placas de chumbo, em torno da região abdominal do manequim. Além disso, foram utilizados dois tipos de filtros: físico, com angulação de 30o, e dinâmico. Através de uma câmara de ionização cilíndrica posicionada na região fetal do simulador, verificou-se que, ao final do tratamento mamário, a dose de radiação periférica atinge valores entre 3,90 e 48,67 cGy quando se irradia com o filtro físico, e entre 1,75 e 13,78 cGy para o filtro dinâmico; ambos com a blindagem. Através dos dados obtidos, conclui-se que a implantação do filtro físico incrementa a dose periférica devido ao aumento da intensidade da radiação de fuga e ao espalhamento causado pelo material atenuador. Além disso, a blindagem empregada não foi suficiente para bloquear toda radiação secundária: Ao se empregar o filtro em cunha, segundo a literatura, as doses podem ser capazes de induzir o retardo mental e o câncer durante a vida pós-nascimento. Já com o filtro dinâmico esses riscos são reduzidos drasticamente, chegando a ser ínfimos.When a pregnant woman is submitted to breast radiotherapy, the fetus may be seriously affected by the peripheral dose. In order to verify that dose, a humanoid phantom, was irradiated at the left breast. The phantom is an adapted manikin, with some materials (densities close to water) inside and outside of it. The irradiation was done using a 6 MeV x-ray beam energy from a linear accelerator “Clinac 600C”. During the irradiation, a shield around the abdominal area of the manikin, consisting of blocks and slabs of lead was used. In addition, two types of filters were used: a physical, with 30o angulation, and an enhanced dynamic one. Through a cylindrical ionization chamber, positioned in the simulator ́s fetal region, it was found that, at the end of the breast treatment, the peripheral doses reach values between 3.90 and 48.67 cGy, when the physical wedge was used. With the application of the enhanced dynamic wedge, the values were between 1.75 and 13.78 cGy. According to the obtained data, the physical wedge can increase the peripheral dose due to the larger background radiation intensity and to the scattering caused by the attenuator material. In addition, the shielding couldn ́t block all the secondary radiation, which, according to the literature, can be able to induce mental retardation and cancer during postnatal life. However, the induction to these effects is negligible, when the type of wedge was changed.
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Cashmore, Jason. "Operation, characterisation & physical modelling of unflattened medical linear accelerator beams and their application to radiotherapy treatment planning." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4616/.
Full textAbstract:
The flattening filter is a conical shaped piece of metal sitting within the treatment head of a linear accelerator, used to produce a flat, uniform beam of X-rays from the forward-peaked distribution exiting the target. Despite their routine use since the introduction of the linac in the 1950’s, however, there are still several unresolved issues surrounding their use. The photon scatter and electron contamination introduced by modifying the fluence are difficult to model, as is the variation in energy spectrum caused by differential absorption across the field. Leakage radiation also causes increased whole body doses to the patient, and the filter itself causes acts as an amplifier for beam bending and steering issues. With advances in tumour imaging, dose optimisation and in-room image-guidance it is now possible to locate a tumour accurately in space and to design radiation fields to conform to its shape, avoiding adjacent normal and critical tissues. This active production of non-flat fields means that the prerequisite for flat fields no longer exists, and the filter is potentially no longer a necessary component. This thesis reports on research to produce a filter-free linear accelerator, from basic operation and optimisation, dosimetric characterisation and beam modelling, through to treatment planning and dose delivery. FFF beams have been shown reduce many of the problems seen with the current generation of linear accelerators, producing beams that are inherently more stable, simple to model and with reduced patient leakage (leading to reduced secondary cancers). The increase in dose rate also translates into shorter treatment times for many treatments, aiding patient comfort and reducing problems associated with intra-fraction motion.
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Mansouri, Imène. "Long-Term Kidney and Cardiac Disease Following Childhood Cancer Treatment." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS579.
Full textAbstract:
Les progrès thérapeutiques ont conduit à une augmentation de la survie à 5 ans des enfants traités pour un un cancer et qui dépasse actuellement 80%. En France il a été estimé que 50 000 adultes guéris d’un cancer pédiatrique, mais la prévalence des complications à long terme causées par la maladie et par ses traitement dépasse 60% après un suivi de 30 ans. L’objectif général de cette thèse était de faire avancer les connaissances actuelles sur la mortalité et la morbidité à long terme liées aux cancers pédiatriques.Avec les données de la cohorte FCCSS (French Childhood Cancer Survivor Study) qui inclut des sujets ayant été traités pour entre 1946 et 2000 pour un cancer pédiatrique solide, nous avons observé que le risque de mortalité chez ces patients demeure plus élevé que la population générale même à plus de 40 ans après le diagnostic de leur premier cancer. D’autre part, la mortalité liée plus aux effets à long terme des traitements anticancéreux, plus spécifiquement les seconds cancers et maladies circulatoires, a significativement baissé parmi les sujets traités plus récemment.Par ailleurs, nous avons aussi confirmé le rôle des anthracyclines dans la survenue de l’insuffisance cardiaque et montré que la fraction du volume médian du cœur ayant reçu 30 Gray était beaucoup plus élevés chez les sujets ayant développé une insuffisance cardiaque par rapport aux autres. Nous avons aussi observé que des faibles volumes du cœur (10% du volume du ventricule gauche) ayant reçus ≥30 Gy sont associés à un risque élevé de développer une insuffisance cardiaque. Cette étude est la première à rapporter une relation dose-effet basée sur des indicateurs dose-volume et ces résultats peuvent être utilisés dans la pratique clinique couranteNos travaux ont aussi montré que les patients ayant subi une néphrectomie unilatérale étaient à risque de développer une maladie rénale chronique à très long terme. L’effet de la dose de radiation reçue aux reins différait selon si les patients ayant subi une néphrectomie unilatérale ou non . En effet, une dose au seul rein même <5Gy était associée à un risque élevé de dysfonctionnement rénal. Par ailleurs, grâce aux données du registre REIN, nous avons pu montrer que l’incidence de l’insuffisance rénale terminale liée aux anticancéreux était en train d’augmenter au fil des années. Cependant ces patients étaient moins inscrits en liste d'attente comparés à d’autres malades rénaux et avaient par conséquent un accès très limité à la transplantation rénale.En conclusion, le travail effectué courant cette thèse pourrait aider à identifier les patients à risque accru de complications tardives majeures liées aux traitements anticancéreux. Nos résultats pourraient être utilisés dans la pratique clinique courante pour l’adaptation de la prise en charge thérapeutique des enfants atteints de cancer et pour les recommandations de leurs suivi à long termeAdvances in treatment have increased the overall 5-year survival rate for childhood cancers to approximately 80%. In France, it estimated that about 50,000 adults have survived childhood cancer. However, previous studies have demonstrated that by the second decade of life, more than 60% of survivor of childhood malignancies (CCS) will suffer from at least one chronic disease related to the treatment they have received.The general objective of this thesis was to advance knowledge about the very long morbidity associated with childhood cancer, with the ultimate target to improve both the long term outcome and quality of life of survivors.Using data from the French Childhood Cancer Survivor Study (FCCSS) cohort, which includes patients treated for a solid pediatric malignancy between 1942 and 2000, we found that that mortality among CCS remained higher than the general population even after more than 40 years of the primary cancer diagnosis. A major finding of this study was that mortality attributed to adverse effects of cancer treatments (secondary primary neoplasm and circulatory disease) declined among patients treated in more recent treatment periods. We also conducted a case control study nested in the FCCSS cohort and further affirmed the role of anthracycline in the occurrence of heart failure. We demonstrated that the median heart volume that received at least 30Gy was higher among heart failure cases and that exposing small volumes of the heart (10% of the volume of the left ventricle) to at least 30Gy was associated with an elevated risk of cardiac failure. This study was the first to derive a dose response relationship based on dose-volume metrics which can be used in current clinical practice.Our results also showed that unilateral nephrectomy was associated with a high risk of renal impairment. The effect of radiation dose to the kidneys was also different among nephrectomized patients for whom any exposure to radiation was associated with an elevated risk of chronic kidney disease even at doses less than 5 Gy.Furthermore, data from the renal epidemiology and information network (REIN) registry allowed us to investigated ESKD (end stage kidney disease) related to nephrotoxic chemotherapy and/or radiation. Our registry-based study showed that ESKD related to nephrotoxic cancer treatment has been steadily increasing over the past decade in the French population. These patients experienced a much lower rate of wait-listing than matched controls with other causes of ESKD, despite similar survival on dialysis.To conclude the results of this thesis are useful to identify survivors of childhood malignancies who are at risk of developing severe long term adverse effects related to the treatment of their primary cancer. Our results could be applied in current clinical practice to help adapt current treatment strategies and improve the long-term follow-up recommendations of childhood cancer survivors