Zeitschriftenartikel: „Dose-at-volume“

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Appenzoller, Lindsey M., Jeff M. Michalski, Wade L. Thorstad, Sasa Mutic und Kevin L. Moore. „Predicting dose-volume histograms for organs-at-risk in IMRT planning“. Medical Physics 39, Nr. 12 (27.11.2012): 7446–61. http://dx.doi.org/10.1118/1.4761864.

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Wibowo, R. Arif, Bambang Haris und dan Inganatul Islamiyah. „Dose evaluation of organs at risk (OAR) cervical cancer using dose volume histogram (DVH) on brachytherapy“. Journal of Physics: Conference Series 853 (Mai 2017): 012013. http://dx.doi.org/10.1088/1742-6596/853/1/012013.

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Сухих, Е., E. Sukhikh, Л. Сухих, L. Sukhikh, О. Аникеева, O. Anikeeva, П. Ижевский, P. Izhevsky, И. Шейно und I. Sheino. „Dosimetric Evaluation for Various Methods of Combined Radiotherapy of Cervical Cancer“. Medical Radiology and radiation safety 64, Nr. 1 (20.01.2019): 45–52. http://dx.doi.org/10.12737/article_5c55fb4a074ee1.27347494.

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Purpose: Carrying out dosimetric investigation of possibility to replace a traditional combined radiation therapy of cervical cancer by combinations only external irradiation, without change of total course dose and number of fractions. Material and Methods: Eleven patients with a diagnosis of cervical cancer (stages T2bNxM0 and T3NxM0) who received a course of combined radiotherapy (CRT) have been considered in this study. The combination of dose delivery techniques 3D-CRT + high dose rate brachytherapy (HDR) was used as a basic one. The following fractionation regimes for CRT were simulated: external beam RT (EBRT) of the first stage – total dose 50 Gy and fraction dose 2 Gy (25 fractions), the second stage – total dose 28 Gy and fraction dose 7 Gy (4 fractions). Total CRT course dose was 89.7 Gy EQD2. Dosimetric planning of EBRT using conventional radiography and 3D-CRT has been carried out using XIO dosimetry planning system. Dosimetric planning of first-stage EBRT and second-stage EBRT using the VMAT technique has been performed in the Monaco dosimetry planning system. HDR of the second stage has been planned using the HDRplus dosimetric planning system for the Multisource HDR unit with a 60Co source. Results: Coverage of the clinical volume of the tumor using HDR, on average, was equal to 95 % of the prescribed dose at 91.8 % of the volume, 110 % of the dose – 75.7 % of the volume. 60Co + VMAT results in the coverage level 95 % of the dose at 97.1 % of the volume and 110 % of the dose at 2.1 % of the volume. 3D-CRT + VMAT provide the coverage level of 95 % of the dose at 98 % of the volume and 110 % of the dose at 2.6 % of the volume. Using the combination VMAT + VMAT allows achieving the average coverage of the target at the level of 98 % of the dose at 97 % of the volume, 110 % of the dose at 8.8 % of the volume. The maximum dose per volume of the organs at risk equal to 2 cm3 did not exceed their tolerant levels both for the bladder and for the rectum. Conclusion: At present, there is a technical possibility to replace the second stage of CRT cervical cancer by EBRT using the VMAT technique. Implementation of the VMAT technique allows to increase the uniformity of irradiated volume coverage comparing with traditional HDR. While using VMAT technique the tolerant levels of organs at risk are not exceeded.

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Kierkels, Roel G. J., Albin Fredriksson, Stefan Both, Johannes A. Langendijk, Daniel Scandurra und Erik W. Korevaar. „Automated Robust Proton Planning Using Dose-Volume Histogram-Based Mimicking of the Photon Reference Dose and Reducing Organ at Risk Dose Optimization“. International Journal of Radiation Oncology*Biology*Physics 103, Nr. 1 (Januar 2019): 251–58. http://dx.doi.org/10.1016/j.ijrobp.2018.08.023.

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Gotz, Malte, Leonhard Ka, Heikki Tölli und Jörg Pawelke. „Correction for volume recombination in liquid ionization chambers at high dose‐per‐pulse“. Medical Physics 46, Nr. 8 (14.06.2019): 3692–99. http://dx.doi.org/10.1002/mp.13600.

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Hüttenrauch, P., M. Witt, D. Wolff, S. Bosold, R. Engenhart-Cabillic, J. Sparenberg, H. Vorwerk und K. Zink. „Target volume coverage and dose to organs at risk in prostate cancer patients“. Strahlentherapie und Onkologie 190, Nr. 3 (16.01.2014): 310–16. http://dx.doi.org/10.1007/s00066-013-0483-2.

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Poddar, Jyoti, Ashutosh Das Sharma, U. Suryanarayan K, Sonal Patel Shah und Ankita Parikh. „Dosimetric analysis of the effect of bladder volume on brachytherapy dose to organs at risk (OARs) in volume based intracavitary brachytherapy of carcinoma cervix: An institutional study.“ Journal of Clinical Oncology 35, Nr. 15_suppl (20.05.2017): e17006-e17006. http://dx.doi.org/10.1200/jco.2017.35.15_suppl.e17006.

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e17006 Background: External beam radiotherapy combined with intracavitary brachytherapy is the standard of care in Carcinoma cervix. Due to its characteristics of rapid dose fall off, brachytherapy limits the toxicity to organs at risk while escalating radiation dose to target. Still, the organs near the radioactive source are at risk of considerable exposure, toxicity and post treatment morbidity. Alteration of bladder volume, alters the relative anatomy of uterus, rectum, sigmoid colon causing changes in the radiation dose to these organs. Methods: Aim:To correlate between the bladder volume and its effects on the dose received by bladder, rectum and sigmoid colon in volume based HDR brachytherapy in carcinoma cervix.30 patients (78 Intracavitary Brachytherapy applications) of Carcinoma Cervix (FIGO stage II-III) treated with EBRT followed by volume based HDR brachytherapy at our institute between July 2014 to Jan 2016 were studied. Bladder volume data was tabulated into five groups according to increasing volume of bladder. It was correlated with D2cc dose received by bladder, rectum and sigmoid colon. Results: Statistical Analysis Linear regression and correlation analysisof the HRCTV with dose to the bladder was 0.2 (.i.e HRCTV does not influence the bladder dose.) Pearson correlation of bladder volume and D2cc bladder and D2cc rectum was positive for all groups and for sigmoid D2cc was positive for group B and negative for all other groups. P value = 0.064 Conclusions: Keeping the bladder volume low (<130 cc) during brachytherapy would reduce the dose to bladder and rectum and the probability of late bladder and rectal toxicity reduces. [Table: see text]

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Embring, Anna, Eva Onjukka, Claes Mercke, Ingmar Lax, Anders Berglund, Sara Bornedal, Berit Wennberg, Emmy Dalqvist und Signe Friesland. „Re-Irradiation for Head and Neck Cancer: Cumulative Dose to Organs at Risk and Late Side Effects“. Cancers 13, Nr. 13 (25.06.2021): 3173. http://dx.doi.org/10.3390/cancers13133173.

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Re-irradiation in head and neck cancer is challenging, and cumulative dose constraints and dose/volume data are scarce. In this study, we present dose/volume data for patients re-irradiated for head and neck cancer and explore the correlations of cumulative dose to organs at risk and severe side effects. We analyzed 54 patients re-irradiated for head and neck cancer between 2011 and 2017. Organs at risk were delineated and dose/volume data were collected from cumulative treatment plans of all included patients. Receiver–operator characteristics (ROC) analysis assessed the association between dose/volume parameters and the risk of toxicity. The ROC-curve for a logistic model of carotid blowout vs. maximum doses to the carotid arteries showed AUC = 0.92 (95% CI 0.83 to 1.00) and a cut-off value of 119 Gy (sensitivity 1.00/specificity 0.89). The near-maximum dose to bones showed an association with the risk of osteoradionecrosis: AUC = 0.74 (95% CI 0.52 to 0.95) and a cut-off value of 119 Gy (sensitivity 1.00/specificity 0.52). Our analysis showed an association between cumulative dose to organs at risk and the risk of developing osteoradionecrosis and carotid blowout, and our results support the existing dose constraint for the carotid arteries of 120 Gy. The confirmation of these dose–response relationships will contribute to further improvements of re-irradiation strategies.

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Kukolowicz, Pawel F., und Bernard J. Mijnheer. „Comparison between dose values specified at the ICRU reference point and the mean dose to the planning target volume“. Radiotherapy and Oncology 42, Nr. 3 (März 1997): 271–77. http://dx.doi.org/10.1016/s0167-8140(97)01905-1.

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Desai, Anand, Joshua B. Stoker, Cody A. Wages, X. Ron Zhu und Andrew Lee. „Rectal dose-volume differences for scanning proton beam therapy with or without an endorectal balloon for the treatment of prostate cancer.“ Journal of Clinical Oncology 31, Nr. 6_suppl (20.02.2013): 243. http://dx.doi.org/10.1200/jco.2013.31.6_suppl.243.

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243 Background: Endorectal balloons (ERB) are routinely used in proton radiation for prostate cancer (PCa). The dosimetric implications, however, in conjunction with scanning proton beam therapy (SPT) have not been studied. We sought to describe dose-volume values with the use of an ERB vs no ERB for SPT for PCa. Methods: We analyzed 10 patients with localized PCa. Each patient underwent two CT simulations, one with a water-filled ERB (50-60 ml) and one with no ERB. For 8 patients, the prostate and proximal 1 cm of the seminal vesicles was the clinical target volume (CTV), with the prostate only as CTV for 2 patients. We defined 3 structures: rectum (R), anterior rectal wall (ARW) as a 3 mm rim of the anterior half of the rectum, and AR-CTV as the ARW only on slices with a contoured CTV. SPT plans were created in both cases for each patient, with the creation of a scanning target volume (STV), which expanded the CTV by 6 mm in all dimensions except 4 mm posteriorly and 12 mm laterally. Two opposed lateral beams were used to plan to the STV. Total dose was 78 Co-60 Gy equivalent in 39 fractions, to cover 95% of the STV. RBE was 1.1. We compared the dose-volume values for the R, ARW, and AR-CTV between the two arms. Results: The ERB significantly increased the R volume for all cases (61 ± 11 ml vs 105 ± 10 ml (p<0.01)). Rectal volumes radiated for all cases: V10, 55%; V50, 23%; and V70, 11%. The ERB significantly decreased the R volume radiated for all dose levels V5-V82 (p<0.05). The absolute difference was larger at low dose levels (8% at V10) and intermediate dose levels (5% at V50) compared to high dose levels (3% at V70). For the ARW, the ERB did not significantly change the volume radiated at any dose level. For the AR-CTV, the ERB significantly decreased the volume radiated for dose levels V20-V60 (p<0.05). Conclusions: The ERB provided a significant decrease in R volume radiated at all dose levels, and significantly decreased the AR-CTV volume, which represents a high risk volume, radiated at intermediate dose levels. Rectal doses with SPT, however, were low whether using an ERB or not. In the setting of the low rectal doses delivered, further study regarding the clinical benefit is warranted.

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Farhiyati, Wida, Rinarto Subroto, I. Wayan Ari Makmur, Nurul Qomariyah und Rahadi Wirawan. „TREATMENT PLANNING SYSTEM (TPS) KANKER PAYUDARA MENGGUNAKAN TEKNIK 3DCRT“. ORBITA: Jurnal Kajian, Inovasi dan Aplikasi Pendidikan Fisika 6, Nr. 1 (10.05.2020): 150. http://dx.doi.org/10.31764/orbita.v6i1.2115.

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ABSTRAKPenelitian ini bertujuan untuk mengevaluasi hasil simulasi TPS teknik 3DCRT pada kasus kanker payudara agar sesuai dengan standar yang diizinkan International Commission on Radiation Units and Measurements (ICRU). Proses TPS menggunakan program Eclipse dengan algoritma Anisotropic Analytical Algorithm. Kurva histogram dosis volume kumulatif 3DCRT dianalisis untuk mendapatkan dosis radiasi yang diterima organ at risk (OAR) paru-paru kiri, paru-paru kanan dan jantung. Hasil TPS menunjukkan dosis yang diterima OAR berada di bawah batas ambang yang ditentukan yaitu paru-paru kiri dengan mean dose 54,7 cGy yang melingkupi volume 1238,5 cm3 dan pada paru-paru kanan dosis mean dose 2113,2 cGy melingkupi volume 1474,5 cm3 serta pada jantung mean dose 96,5 cGy melingkupi volume 175,5 cm3. Simulasi TPS yang dilakukan berhasil mendapatkan data perencanaan penyinaran kasus kanker payudara yang memenuhi syarat dosis relatif yang melingkupi volume PTV yang diizinkan ICRU (volume terlingkupi 95%-107%) yaitu besarnya dosis relatif untuk target sebesar 95% yang melingkupi 95,5% volume target. Kata kunci: radioterapi, TPS, dosis, PTV, OAR. ABSTRACTThis study objective is to evaluate the simulation results of the 3DCRT technique TPS in breast cancer cases to conform to the standards permitted by the International Commission on Radiation Units and Measurements (ICRU). The TPS process uses the Eclipse program with the Anisotropic Analytical Algorithm algorithm. The 3DCRT cumulative dose-volume histogram curve was analyzed to obtain the absorbed dose received by the organ at risk (OAR) of the left lung, right lung and heart. The TPS results show that the dose received by OAR was below the prescribed threshold of the left lung with a mean dose of 54.7 cGy covering a volume of 1238.5 cm3 and to the right lung the mean dose of 2113.2 cGy surrounding the volume of 1474, 5 cm3 and at the heart the mean dose of 96.5 cGy covers a volume of 175.5 cm 3. TPS simulation carried out successfully obtained data on the planning of radiation from breast cancer cases that met the relative dosage requirements that covered the volume of PTV permitted by ICRU (95% -107% enclosed volume), that is, the relative dose for the target of 95% which covered 95.5% of the target volume. Keywords: radiotherapy, TPS, dose, PTV, OAR.

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Siavashpour, Zahra, Mahmoud Reza Aghamiri, Ramin Jaberi, Hamid Reza Dehghan Manshadi, Reza Ghaderi und Christian Kirisits. „Optimum organ volume ranges for organs at risk dose in cervical cancer intracavitary brachytherapy“. Journal of Contemporary Brachytherapy 2 (2016): 135–42. http://dx.doi.org/10.5114/jcb.2016.59687.

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Moore, K. L., L. M. Appenzoller, J. Tan, J. M. Michalski, W. L. Thorstad und S. Mutic. „Clinical implementation of dose-volume histogram predictions for organs-at-risk in IMRT planning“. Journal of Physics: Conference Series 489 (24.03.2014): 012055. http://dx.doi.org/10.1088/1742-6596/489/1/012055.

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Llanas, D., J. Bézin, A. Ben Abdennebi, C. Veres, D. Lefkopoulos, F. de Vathaire und I. Diallo. „Inter-operator variability in organs at risk delineation: Their effects on dose-volume histograms“. Physica Medica 29 (Juni 2013): e39. http://dx.doi.org/10.1016/j.ejmp.2013.08.122.

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Appenzoller, L., S. Mutic, J. M. Michalski, W. L. Thorstad und K. L. Moore. „Predicting Dose-volume Histograms for Organs at Risk in Intensity Modulated Radiation Therapy Planning“. International Journal of Radiation Oncology*Biology*Physics 84, Nr. 3 (November 2012): S79—S80. http://dx.doi.org/10.1016/j.ijrobp.2012.07.311.

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Rosewall, Tara, Vickie Kong, Robert Heaton, Geoffrey Currie, Michael Milosevic und Janelle Wheat. „The Effect of Dose Grid Resolution on Dose Volume Histograms for Slender Organs at Risk during Pelvic Intensity-modulated Radiotherapy“. Journal of Medical Imaging and Radiation Sciences 45, Nr. 3 (September 2014): 204–9. http://dx.doi.org/10.1016/j.jmir.2014.01.006.

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Chow, James C. L., Runqing Jiang und Daniel Markel. „Dosimetric variations in calculation grid size in prostate VMAT: a dose-volume histogram analysis using the Gaussian error function“. Journal of Radiotherapy in Practice 17, Nr. 2 (23.11.2017): 162–70. http://dx.doi.org/10.1017/s1460396917000619.

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AbstractBackgroundVarying the calculation grid size can change the results of dose-volume and radiobiological parameters in a treatment plan, and therefore has an impact on the treatment planning quality assurance.PurposeThis study investigated the dosimetric influence of the calculation grid size variation in the prostate volumetric modulated arc therapy (VMAT) plan.Methods and materialsDose distributions of 10 prostate VMAT plans were acquired using calculation grid sizes of 1–5 mm. Dose-volume histogram (DVH) analysis was carried out to determine the dose-volume variation corresponding to the grid size change using the Gaussian error function (GEF). At the same time, dose-volume points, dose-volume parameters and radiobiological parameters were calculated based on DVHs of targets and organs at risk (OARs) for each grid size.ResultsComparing percentage variations of GEF parameters between the planning target volume (PTV) and clinical target volume (CTV), GEF parameters of the PTV were found varied more significantly than the CTV. This resulted in larger variations of dose-volume (%ΔCI=40·02 versus 13·55%, %ΔHI=12·45 versus 2·93% and %ΔGI=0·22 versus 0·06%) and radiobiological parameters (%ΔTCP=0·61 versus 0·25% and %ΔEUD=2·11 versus 0·26%) of the PTV compared with CTV. For OARs, the rectal wall showed a larger dose-volume variation than the rectum. However, similar dose-volume variation due to grid size change was not found in the bladder, bladder wall and femur.ConclusionsKnowing the dosimetric variation in this study is important to the radiotherapy staff in the quality assurance for the prostate VMAT planning.

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Ma, T., und IZ Wang. „SU-E-T-530: Correlating Dose-Volume Histogram Results with Overlapping Volume of Organ-At-Risk and Planning Target Volume for Prostate IMRT“. Medical Physics 41, Nr. 6Part20 (29.05.2014): 349. http://dx.doi.org/10.1118/1.4888864.

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Chakravarty, N., M. K. Semwal, G. Trivedi, V. Suhag, M. Jain, N. Sharma und R. S. Vashisth. „Image-based 3D dosimetric studies with high dose rate intracavitary brachytherapy of cervical cancer“. Journal of Radiotherapy in Practice 19, Nr. 3 (30.09.2019): 277–80. http://dx.doi.org/10.1017/s1460396919000712.

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AbstractAim:To study 2D and 3D dosimetric values for bladder and rectum, and the influence of bladder volume on bladder dose in high dose rate (HDR) intracavitary brachytherapy (ICBT). The large patient data incorporated in this study would better represent the inherent variations in many parameters affecting dosimetry in HDR-ICBT.Material and Methods:We prospectively collected data for 103 consecutive cervical cancer patients (over 310 HDR fractions) undergoing CT-based HDR-ICBT at our centre. Correlation among bladder and rectum maximum volume doses and corresponding International Commission on Radiation Units and Measurement (ICRU) point doses were estimated and analysed. Impact of bladder volume on bladder maximum dose was assessed.Results:The ICRU point doses to bladder and rectum varied from the volumetric doses to these organs. Further, bladder volume poorly correlated with bladder maximum dose for volume variations encountered in the clinical practice at our centre.Findings:ICRU point doses to bladder and rectum are less likely to correlate with long-term toxicities to these organs. Further, in clinical practice where inter-fraction bladder volume does not vary widely there is no correlation between bladder volume and bladder dose.

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Chirikova, Ekaterina, Elizabeth K. Cahoon, Alexander Rozhko, Vladimir Drozdovitch, Mark P. Little, Robert J. McConnell, Victor Minenko et al. „Association Between 131I Exposure After the Chernobyl Accident and Thyroid Volume in Children in Belarus“. Journal of the Endocrine Society 5, Supplement_1 (01.05.2021): A856—A857. http://dx.doi.org/10.1210/jendso/bvab048.1748.

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Abstract Thyroid enlargement can cause problems with swallowing or breathing and a decrease in accuracy of screening for thyroid cancer. Exposure to radioactive iodines after the 1986 Chernobyl accident is known to increase risk of thyroid cancer in those exposed at a young age, but little is known about its effects on thyroid volume, which could have important clinical implications. The objective of this study is to characterize the dose-response association between iodine-131 (131I) exposure and thyroid volume using data from a Belarusian-American cohort study of residents of Belarus exposed during childhood. Persons exposed to Chernobyl fallout in Belarus at the age of 18 years or younger had individual 131I doses to the thyroid gland estimated from direct thyroid activity measurements, radioecological and biokinetic models, and interview data on whereabouts and dietary habits collected during baseline screening in 1996-2001 (N=11,970; median age 21 years). Thyroid volume was estimated from thyroid ultrasound measurements during screening. Individuals with diagnoses of benign or malignant tumors of thyroid gland, any thyroid surgery or aplasia, and missing thyroid volume measurements were excluded (n=1,104). Dose and thyroid volume were log-transformed due to right-skewed distributions. We used a multivariable linear regression to estimate the dose-response association between 131I dose to the thyroid and thyroid volume accounting for confounding effects of sex, age at screening, and place of residence at the time of screening, a proxy for endemic iodine deficiency. To examine nonlinear effects, we added a quadratic term for the log-transformed dose. Among 10,866 participants, dose to thyroid ranged from 0.0005 to 39 gray (Gy) (median=0.3 Gy). In a linear regression model adjusted for confounders, log thyroid volume was best described by a linear-quadratic function of log dose (p<0.001 for log dose and log dose-squared coefficients). The largest effect was observed for doses 0.3-0.6 Gy (14%), then gradually decreased. Subjects with thyroid dose of 1 Gy had an average thyroid volume 13.6% (95% CI 8- 19.2%) higher compared to those with dose 1 mGy. Thyroid volume increased with age and was significantly higher for males compared to females and for those from Minsk city and area compared to other regions (both p<0.001). The adjusted R2-value was 30%, suggesting unaccounted factors that might better explain this association. This is the first study to assess the dose-response association between exposure to 131I and thyroid volume. Although statistically significant, the observed increase in thyroid volume with dose was small. Availability of measurements of iodine deficiency and dietary habits around the time of an accident in the future studies of nuclear accidents will be essential for understanding the mechanism of association between radiation dose and thyroid volume in young people.

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Torrens, Michael, Caroline Chung, Hyun-Tai Chung, Patrick Hanssens, David Jaffray, Andras Kemeny, David Larson et al. „Standardization of terminology in stereotactic radiosurgery: Report from the Standardization Committee of the International Leksell Gamma Knife Society“. Journal of Neurosurgery 121, Suppl_2 (Dezember 2014): 2–15. http://dx.doi.org/10.3171/2014.7.gks141199.

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ObjectThis report has been prepared to ensure more uniform reporting of Gamma Knife radiosurgery treatment parameters by identifying areas of controversy, confusion, or imprecision in terminology and recommending standards.MethodsSeveral working group discussions supplemented by clarification via email allowed the elaboration of a series of provisional recommendations. These were also discussed in open session at the 16th International Leksell Gamma Knife Society Meeting in Sydney, Australia, in March 2012 and approved subject to certain revisions and the performance of an Internet vote for approval from the whole Society. This ballot was undertaken in September 2012.ResultsThe recommendations in relation to volumes are that Gross Target Volume (GTV) should replace Target Volume (TV); Prescription Isodose Volume (PIV) should generally be used; the term Treated Target Volume (TTV) should replace TVPIV, GTV in PIV, and so forth; and the Volume of Accepted Tolerance Dose (VATD) should be used in place of irradiated volume. For dose prescription and measurement, the prescription dose should be supplemented by the Absorbed Dose, or DV% (for example, D95%), the maximum and minimum dose should be related to a specific tissue volume (for example, D2% or preferably D1 mm3), and the median dose (D50%) should be recorded routinely. The Integral Dose becomes the Total Absorbed Energy (TAE). In the assessment of planning quality, the use of the Target Coverage Ratio (TTV/ GTV), Paddick Conformity Index (PCI = TTV2/[GTV · PIV]), New Conformity Index (NCI = [GTV · PIV]/TTV2), Selectivity Index (TTV/PIV), Homogeneity Index (HI = [D2% –D98%]/D50%), and Gradient Index (GI = PIV0.5/PIV) are reemphasized. In relation to the dose to Organs at Risk (OARs), the emphasis is on dose volume recording of the VATD or the dose/volume limit (for example, V10) in most cases, with the additional use of a Maximum Dose to a small volume (such as 1 mm3) and/or a Point Dose and Mean Point Dose in certain circumstances, particularly when referring to serial organs. The recommendations were accepted by the International Leksell Gamma Knife Society by a vote of 92% to 8%.ConclusionsAn agreed-upon and uniform terminology and subsequent standardization of certain methods and procedures will advance the clinical science of stereotactic radiosurgery.

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Yuasa, Masahiro, und Hiromasa Kurosaki. „Noncoplanar Radiation using Tomotherapy: A Phantom Study“. Technology in Cancer Research & Treatment 19 (01.01.2020): 153303382094577. http://dx.doi.org/10.1177/1533033820945776.

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Background: There are very few studies on noncoplanar radiation in tomotherapy because deformable image registration is not implemented in the TomoTherapy Planning Station, a treatment planning device used in tomotherapy. This study examined whether noncoplanar radiation can be performed on the head using a tilt-type head and neck fixture and deformable image registration. Methods: Planning target volume spheres with diameters of 2, 3, and 4 cm were set on a head phantom, and computed tomography images were taken at 0° and 40° using a tilt-type head and neck fixture. Irradiation plans were created in the Tomotherapy Planning Station. Noncoplanar radiation was simulated, and the dose volume was evaluated by adding the 0° dose distribution and 40° dose distribution using the deformable image registration of the RayStation treatment planning system. Results: The ratio of the phantom volume to the irradiation dose for 20% to 30% of the planning target volume in noncoplanar radiation was smaller than that for 40% to 90% of the planning target volume in single-section irradiation at 0° or 40°. Conclusions: Noncoplanar radiation on the head region using tomotherapy was possible by using a tilt-type head and neck fixture, and the dose distribution could be evaluated using deformable image registration. This method helps reduce the dose of the organ-at-risk region located slightly away from the planning target volume.

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Huddart, Robert, Fiona McDonald, Shaista Hafeez, Karole Warren-Oseni, Helen Taylor, Alan Thompson, Vincent Khoo et al. „Phase I dose-escalated image-guided adaptive bladder radiotherapy study: Results of first dose cohort (68Gy).“ Journal of Clinical Oncology 32, Nr. 4_suppl (01.02.2014): 291. http://dx.doi.org/10.1200/jco.2014.32.4_suppl.291.

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291 Background: Prospective study assessing the safety of dose escalation in the treatment of localised muscle-invasive bladder cancer using image-guided adaptive radiotherapy (RT) with a reduced high-dose tumour volume. Methods: Radical RT was planned and delivered in 3 phases. Phase I was delivered to the empty whole bladder (10Gy 5#). Bladder variation assessed on phase I daily imaging was used to determine the adaptive approach for phase III (composite volume or plan of the day). Phase II was delivered to a tumour boost volume on a partially filled bladder (18Gy 9# if normal tissue dose-constraints were met, or to 14Gy 7# if they were not). The adaptive phase III (40Gy 20#) was delivered to the empty whole bladder. The primary endpoint was late RTOG toxicity. Results: Of the twenty-six patients recruited to 68Gy, 20 patients met the normal tissue constraints for dose escalation. For the phase III adaptive technique, 14 patients were treated with a composite volume approach and 12 with a plan of the day. At median follow-up of 24 months, 13 (65%) dose escalated patients remain alive and disease free. Within this dose cohort there has been 1 muscle invasive local recurrence, 1 superficial recurrence and 1 patient has developed metastases. 5 patients in the dose-escalated group have died; 3 from cardiac events, 1 from hospital acquired pneumonia and 1 from metastatic bladder cancer. 1 patient in the dose-escalated group has experienced grade 3 late toxicity (cystitis) occurring 24.6 months after the end of radiotherapy. Conclusions: Image-guided adaptive RT techniques with reduced high-dose volume allow tumour dose-escalation. Toxicity data to date suggest tolerability of 68Gy. Local disease control rates are promising. Trial recruitment continues at 70Gy using intensity modulated radiotherapy technique to deliver a simultaneous integrated boost. Clinical trial information: 7653.

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Abdennebi, A. Ben, J. Chavaudra, M. Besbes, C. Veres, T. Girinsky, A. Bridier, D. Lefkopoulos, F. de Vathaire und I. Diallo. „Évaluation de dose−volume pour les organes à risque et pour le remaining volume at risk (RVR) en radiothérapie externe“. Cancer/Radiothérapie 16, Nr. 5-6 (September 2012): 520. http://dx.doi.org/10.1016/j.canrad.2012.07.017.

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Murray, Julia, Jamie Dean, Helen Mossop, Clare Griffin, Emma Hall, David P. Dearnaley und Sarah Gulliford. „Effect of dose to penile bulb (PB) on patient and clinician-reported erectile function (EF) in standard (SF) and hypofractionated (HF) prostate IGRT.“ Journal of Clinical Oncology 35, Nr. 6_suppl (20.02.2017): 71. http://dx.doi.org/10.1200/jco.2017.35.6_suppl.71.

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71 Background: PB dose has been hypothesised as predictor of EF post RT, however, PB dose volume effects are not well established. We determined PB dose response characteristics & dose volume constraints using data from randomised trial of prostate IGRT with patient (PRO) & clinician reported (CRO) outcomes. Methods: 293 men were treated within CHHiP IGRT substudy (CRUK/06/16) & randomised to receive 2Gy (SF) or 3Gy (HF) per fraction, without or with daily online IGRT with standard (SM) or reduced (RM) CTV-PTV margins. EF was assessed with RMH CRO & at one time-point (>3 years after RT) with IIEF-5. Men were excluded if impotent at baseline. Planning CT & dose distributions were imported into analysis software (VODCA) & PB contoured. All dose distributions were converted into EQD2 (α/β ratio 3Gy), a separate analysis was done using physical dose (PD) for HF cohort. PB dose volume parameters were analysed & atlases of complication incidence (ACI) evaluated using PRO & CRO. Dose volume constraints using PD & EQD2 were derived using ROC analysis (Youden index) & assessed against the no information rate. Results: Complete dosimetric with CRO & PRO data were available for 175 & 100 men respectively. Of these, men treated with SM vs RM had a higher rate of impotence at 2 & 4 years (49% vs 40% & 47% vs 39%). This was also seen in men recording severe ED (46% vs 37%). ACI indicated a dose volume response. Statistically significant PB dose constraints were derived using EQD2 (SF & HF) & PD for HF cohort (Table). Results using PRO were more pronounced than with CRO. Conclusions: There is a dose volume effect between PB & EF characterised using PRO & CRO. Results suggest that reduction of mean PB dose to <20Gy may lead to an increase of potency preservation rates after prostate RT for both 2Gy & 3Gy schedules. Clinical trial information: ISRCTN97182923. [Table: see text]

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Meesat, Ridthee, Hakim Belmouaddine, Jean-François Allard, Catherine Tanguay-Renaud, Rosalie Lemay, Tiberius Brastaviceanu, Luc Tremblay et al. „Cancer radiotherapy based on femtosecond IR laser-beam filamentation yielding ultra-high dose rates and zero entrance dose“. Proceedings of the National Academy of Sciences 109, Nr. 38 (27.08.2012): E2508—E2513. http://dx.doi.org/10.1073/pnas.1116286109.

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Since the invention of cancer radiotherapy, its primary goal has been to maximize lethal radiation doses to the tumor volume while keeping the dose to surrounding healthy tissues at zero. Sadly, conventional radiation sources (γ or X rays, electrons) used for decades, including multiple or modulated beams, inevitably deposit the majority of their dose in front or behind the tumor, thus damaging healthy tissue and causing secondary cancers years after treatment. Even the most recent pioneering advances in costly proton or carbon ion therapies can not completely avoid dose buildup in front of the tumor volume. Here we show that this ultimate goal of radiotherapy is yet within our reach: Using intense ultra-short infrared laser pulses we can now deposit a very large energy dose at unprecedented microscopic dose rates (up to 1011 Gy/s) deep inside an adjustable, well-controlled macroscopic volume, without any dose deposit in front or behind the target volume. Our infrared laser pulses produce high density avalanches of low energy electrons via laser filamentation, a phenomenon that results in a spatial energy density and temporal dose rate that both exceed by orders of magnitude any values previously reported even for the most intense clinical radiotherapy systems. Moreover, we show that (i) the type of final damage and its mechanisms in aqueous media, at the molecular and biomolecular level, is comparable to that of conventional ionizing radiation, and (ii) at the tumor tissue level in an animal cancer model, the laser irradiation method shows clear therapeutic benefits.

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Martinello, Richard A., James W. Arbogast, Kerri Guercia, Albert E. Parker und John M. Boyce. „Nursing preference for alcohol-based hand rub volume“. Infection Control & Hospital Epidemiology 40, Nr. 11 (19.09.2019): 1248–52. http://dx.doi.org/10.1017/ice.2019.251.

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AbstractBackground:The effectiveness of alcohol-based hand rub (ABHR) is correlated with drying time, which depends on the volume applied. Evidence suggests that there is considerable variation in the amount of ABHR used by healthcare providers.Objective:We sought to identify the volume of ABHR preferred for use by nurses.Methods:A prospective observation study was performed in 8 units at a tertiary-care hospital. Nurses were provided pocket-sized ABHR bottles with caps to record each bottle opening. Nurses were instructed to use the volume of ABHR they felt was best. The average ABHR volume used per hand hygiene event was calculated using cap data and changes in bottle mass.Results:In total, 53 nurses participated and 140 nurse shifts were analyzed. The average ABHR dose was 1.09 mL. This value was greater for non-ICU nurses (1.18 mL) than ICU nurses (0.96 mL), but this difference was not significant. We detected no significant association between hand surface area and preferred average dose volume. The ABHR dose volume was 0.006 mL less per use as the number of applications per shift increased (P = .007).Conclusions:The average dose of ABHR used was similar to the dose provided by the hospital’s automated dispensers, which deliver 1.1 mL per dose. The volume of ABHR dose was inversely correlated with the number of applications of ABHR per shift and was not correlated with hand size. Further research to understand differences and drivers of ABHR volume preferences and whether automated ABHR dosing may create a risk for people with larger hands is warranted.

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Flower, E., V. Do, J. Sykes, C. Dempsey, L. Holloway, K. Summerhayes und D. I. Thwaites. „Deformable image registration for cervical cancer brachytherapy dose accumulation: Organ at risk dose–volume histogram parameter reproducibility and anatomic position stability“. Brachytherapy 16, Nr. 2 (März 2017): 387–92. http://dx.doi.org/10.1016/j.brachy.2016.12.006.

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Moosa, Shayan, Ching-Jen Chen, Dale Ding, Cheng-Chia Lee, Srinivas Chivukula, Robert M. Starke, Chun-Po Yen, Zhiyuan Xu und Jason P. Sheehan. „Volume-staged versus dose-staged radiosurgery outcomes for large intracranial arteriovenous malformations“. Neurosurgical Focus 37, Nr. 3 (September 2014): E18. http://dx.doi.org/10.3171/2014.5.focus14205.

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Object The aim in this paper was to compare the outcomes of dose-staged and volume-staged stereotactic radio-surgery (SRS) in the treatment of large (> 10 cm3) arteriovenous malformations (AVMs). Methods A systematic literature review was performed using PubMed. Studies written in the English language with at least 5 patients harboring large (> 10 cm3) AVMs treated with dose- or volume-staged SRS that reported post-treatment outcomes data were selected for review. Demographic information, radiosurgical treatment parameters, and post-SRS outcomes and complications were analyzed for each of these studies. Results The mean complete obliteration rates for the dose- and volume-staged groups were 22.8% and 47.5%, respectively. Complete obliteration was demonstrated in 30 of 161 (18.6%) and 59 of 120 (49.2%) patients in the dose- and volume-staged groups, respectively. The mean rates of symptomatic radiation-induced changes were 13.5% and 13.6% in dose- and volume-staged groups, respectively. The mean rates of cumulative post-SRS latency period hemorrhage were 12.3% and 17.8% in the dose- and volume-staged groups, respectively. The mean rates of post-SRS mortality were 3.2% and 4.6% in dose- and volume-staged groups, respectively. Conclusions Volume-staged SRS affords higher obliteration rates and similar complication rates compared with dose-staged SRS. Thus, volume-staged SRS may be a superior approach for large AVMs that are not amenable to single-session SRS. Staged radiosurgery should be considered as an efficacious component of multimodality AVM management.

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Gagnon, Patrick James, Sheri Weintraub, Amanda Scott, Deborah Schofield, Tushar Kumar und Therese M. Mulvey. „Systematic improvement of SBRT dose gradients.“ Journal of Clinical Oncology 30, Nr. 34_suppl (01.12.2012): 154. http://dx.doi.org/10.1200/jco.2012.30.34_suppl.154.

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154 Background: Stereotactic body radiation therapy (SBRT) offers excellent local control for early stage lung cancer. SBRT utilizes high fractional doses of radiation in 5 or fewer treatments. Normal tissue risk is substantial necessitating steep dose gradients and conformal plans. The Radiation Therapy Oncology Group (RTOG) has established quality metrics for conformality and dose gradients for SBRT. The conformality ratio is the prescription isodose volume to the planning target volume (PTV). Dose falloff is represented by the ratio of the 50% prescription isodose volume to PTV volume (R50%). We evaluated our approach and identified a systematic method to improve our SBRT plans in a community cancer center setting. Methods: 26 lung nodules were treated with SBRT over 30 months at our institution. RTOG 0915 benchmarks were evaluated. Conformality ratios were excellent in all cases. Dose falloff was measured by the R50% and the 7 cases with the largest R50% were re-planned systematically. The technique included creation of a customized ring structure: PTV volume was multiplied by the maximum allowable ratio to establish an ideal 50% isodose volume and a 2 cm ring structure was created around this: the 50 IDV Ring. Intensity modulated radiation therapy (IMRT) optimization specified a max dose to the 50 IDV Ring of 50% of the prescription. Beam geometry and IMRT objectives were held constant from the initial plan. Results: Conformality ratios were maintained and were excellent in all cases. The 50 IDV Ring resulted in R50% improvements in 5 of 7 cases, 4 of which had at least a 15% improvement (15%, 20.6%, 19.2%, and 20.4%) and 1 of which had a 3.3% improvement. Two cases resulted in 1.8% and 0.5% increases in the ratio representing a small deterioration in dose falloff. Conclusions: A strategically designed ring structure can have an impact on dose falloff around a target volume resulting in improvements in dose gradients for SBRT plans. Whether this benchmark is clinically significant is uncertain but it does provide a useful metric for comparison and quality assurance of SBRT plans. A systematic approach to SBRT planning may help provide the highest possible therapeutic ratio in the setting of optimal beam geometry.

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Kano, Hideyuki, John C. Flickinger, Aya Nakamura, Rachel C. Jacobs, Daniel A. Tonetti, Craig Lehocky, Kyung-Jae Park, Huai-che Yang, Ajay Niranjan und L. Dade Lunsford. „How to improve obliteration rates during volume-staged stereotactic radiosurgery for large arteriovenous malformations“. Journal of Neurosurgery 130, Nr. 6 (Juni 2019): 1809–16. http://dx.doi.org/10.3171/2018.2.jns172964.

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OBJECTIVEThe management of large-volume arteriovenous malformations (AVMs) with stereotactic radiosurgery (SRS) remains challenging. The authors retrospectively tested the hypothesis that AVM obliteration rates can be improved by increasing the percentage volume of an AVM that receives a minimal threshold dose of radiation.METHODSIn 1992, the authors prospectively began to stage anatomical components in order to deliver higher single doses to AVMs > 15 cm3 in volume. Since that time 60 patients with large AVMs have undergone volume-staged SRS (VS-SRS). The median interval between the first stage and the second stage was 4.5 months (2.8–13.8 months). The median target volume was 11.6 cm3 (range 4.3–26 cm3) in the first-stage SRS and 10.6 cm3 (range 2.8–33.7 cm3) in the second-stage SRS. The median margin dose was 16 Gy (range 13–18 Gy) for both SRS stages.RESULTSAVM obliteration after the initial two staged volumetric SRS treatments was confirmed by MRI alone in 4 patients and by angiography in 11 patients at a median follow-up of 82 months (range 0.4–206 months) after VS-SRS. The post–VS-SRS obliteration rates on angiography were 4% at 3 years, 13% at 4 years, 23% at 5 years, and 27% at 10 years. In multivariate analysis, only ≥ 20-Gy volume coverage was significantly associated with higher total obliteration rates confirmed by angiography. When the margin dose is ≥ 17 Gy and the 20-Gy SRS volume included ≥ 63% of the total target volume, the angiographically confirmed obliteration rates increased to 61% at 5 years and 70% at 10 years.CONCLUSIONSThe outcomes of prospective VS-SRS for large AVMs can be improved by prescribing an AVM margin dose of ≥ 17 Gy and adding additional isocenters so that ≥ 63% of the internal AVM dose receives more than 20 Gy.

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Beale, N., B. Evans, F. Plaat, M. O. Columb, G. Lyons und G. M. Stocks. „Effect of epidural volume extension on dose requirement of intrathecal hyperbaric bupivacaine at Caesarean section“. British Journal of Anaesthesia 95, Nr. 4 (Oktober 2005): 500–503. http://dx.doi.org/10.1093/bja/aei200.

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Nakagawa, Keiichi, Atsuo Akanuma, Yukimasa Aoki, Katsuyuki Karasawa, Yasuhito Sasaki, Hans Blattmann und Adorf Coray. „Calculation of complication probability of pion treatment at paul scherrer institute using dose-volume histograms“. Radiation Oncology Investigations 1, Nr. 3 (1993): 173–80. http://dx.doi.org/10.1002/roi.2970010307.

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McDiarmid, Adam K., Peter P. Swoboda, Bara Erhayiem, David P. Ripley, Ananth Kidambi, David A. Broadbent, David M. Higgins, John P. Greenwood und Sven Plein. „Single bolus versus split dose gadolinium administration in extra-cellular volume calculation at 3 Tesla“. Journal of Cardiovascular Magnetic Resonance 17, Nr. 1 (2015): 6. http://dx.doi.org/10.1186/s12968-015-0112-6.

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Wolf, Amparo, Amy Tyburczy, Jason Chao Ye, Girish Fatterpekar, Joshua S. Silverman und Douglas Kondziolka. „The relationship of dose to nerve volume in predicting pain recurrence after stereotactic radiosurgery in trigeminal neuralgia“. Journal of Neurosurgery 128, Nr. 3 (März 2018): 891–96. http://dx.doi.org/10.3171/2016.12.jns161862.

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OBJECTIVEApproximately 75%–92% of patients with trigeminal neuralgia (TN) achieve pain relief after Gamma Knife surgery (GKS), although a proportion of these patients will experience recurrence of their pain. To evaluate the reasons for durability or recurrence, this study determined the impact of trigeminal nerve length and volume, the nerve dose-volume relationship, and the presence of neurovascular compression (NVC) on pain outcomes after GKS for TN.METHODSFifty-eight patients with 60 symptomatic nerves underwent GKS for TN between 2013 and 2015, including 15 symptomatic nerves secondary to multiple sclerosis (MS). High-resolution MRI was acquired the day of GKS. The median maximum dose was 80 Gy for initial GKS and 65 Gy for repeat GKS. NVC, length and volume of the trigeminal nerve within the subarachnoid space of the posterior fossa, and the ratio of dose to nerve volume were assessed as predictors of recurrence.RESULTSFollow-up was available on 55 patients. Forty-nine patients (89.1%) reported pain relief (Barrow Neurological Institute [BNI] Grades I–IIIb) after GKS at a median duration of 1.9 months. The probability of maintaining pain relief (BNI Grades I–IIIb) without requiring resumption or an increase in medication was 93% at 1 year and 84% at 2 years for patients without MS, and 68% at 1 year and 51% at 2 years for all patients. The nerve length, nerve volume, target distance from the brainstem, and presence of NVC were not predictive of pain recurrence. Patients with a smaller volume of nerve (< 35% of the total nerve volume) that received a high dose (≥ 80% isodose) were less likely to experience recurrence of their TN pain after 1 year (mean time to recurrence: < 35%, 32.2 ± 4.0 months; > 35%, 17.9 ± 2.8 months, log-rank test, χ2 = 4.3, p = 0.039).CONCLUSIONSThe ratio of dose to nerve volume may predict recurrence of TN pain after GKS. Prospective studies are needed to determine the optimal dose to nerve volume ratio and whether this will result in longer pain-free outcomes.

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Obajdin, Nevena. „Comparison of two planning techniques (FiF/IMRT) for postoperative radiation therapy of prostate cancer“. Libri Oncologici Croatian Journal of Oncology 48, Nr. 2-3 (21.12.2020): 47–53. http://dx.doi.org/10.20471/lo.2020.48.02-03.09.

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Introduction: Within the past two decades, we made significant progress in radiation therapy for prostate cancer. At UH Rijeka IMRT became the technique of choice for radiation therapy following radical prostatectomy since 2016. Previously, an advanced 3-DCRT technique using the field-in-field (FiF) method was used for dose distribution optimization around target volumes and organs-at-risk. This research has been performed to investigate the influence of planning technique choice (FiF or IMRT) on coverage of target volumes with prescribed dose and organs-at-risk sparing. Materials and methods: Comparison of dose distributions calculated using FiF and IMRT techniques was performed retrospectively for ten patients who underwent postoperative radiotherapy. The prescribed dose for all patients was delivered using IMRT, and for this research, we also calculated dose distributions using the FiF technique. For FiF and IMRT techniques, we used linear accelerator photon beams. To determine the influence of planning technique on dose distribution parameters related to target volumes (GTV, CTV, PTV1, PTV2) were analyzed. For organs-at-risk sparing evaluation (rectum, bladder, femoral heads), we used dose-volume constraints. Results and discussion: The analysis of parameters related to target volumes has shown that most of them had no statistically significant difference (V100%(GTV), V100%(CTV), V95%(PTV2), V95%(PTV1)). For both planning techniques, internationally set dose constraints were achieved. Statistically, we found a significant difference for V100%(PTV2), p=0,000534, and V100%(PTV1), p=0,042944 in favor of IMRT. A statistically significant difference (p=0,045966) was found for the volume of the rectum, which receives 40Gy, and for the volume of femoral heads, which receives 30Gy (p=0,000385), where the sparing is better for IMRT. For dose-volume constraints related to the bladder, no statistically significant differences were found. Conclusion: Results of this research show a statistically significant difference for V100% target volume coverage for PTV1 and PTV2, with better dose coverage accomplished by IMRT. Concerning organs-at-risk sparing, a statistically significant difference in favor of IMRT was found for rectum volume, which receives 40Gy. Expectedly, IMRT was superior to the FiF technique. However, differences between the two planning techniques were relatively small, which points to the fact that the FiF technique is viable as a technique of choice.

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Amsbaugh, Mark J., Mehran B. Yusuf, Jeremy Gaskins, Anthony E. Dragun, Neal Dunlap, Timothy Guan und Shiao Woo. „A Dose–Volume Response Model for Brain Metastases Treated With Frameless Single-Fraction Robotic Radiosurgery: Seeking to Better Predict Response to Treatment“. Technology in Cancer Research & Treatment 16, Nr. 3 (27.12.2016): 344–51. http://dx.doi.org/10.1177/1533034616685025.

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Purpose/Objective(s): To establish a dose–volume response relationship for brain metastases treated with single-fraction robotic stereotactic radiosurgery and identify predictors of local control. Materials/Methods: We reviewed a prospective institutional database of all patients treated for intact brain metastases with stereotactic radiosurgery alone using the CyberKnife robotic radiosurgery system from 2012 to 2015. Tumor response was determined based on Response Evaluation Criteria In Solid Tumors version 1.1. Survival was estimated using the Kaplan-Meier method. Logistic regression modeling was used to identify predictors of outcome and establish a dose–volume response relationship. Receiver operating characteristic curves were constructed to evaluate the predictive capability of the relationship. Results: There were 357 metastases evaluated in 111 patients with a median diameter of 8.14 mm (2.00-40.77 mm). At 6 and 12 months, local control was 86.9% and 82.2%, respectively. For lesions of similar volumes, higher maximum dose, mean dose, and minimum dose (all P values <.05) predicted for better local control. Tumor volume and diameter were strongly correlated, and a dose–volume response relationship was constructed using mean dose per lesion diameter (Gy/mm) that was predictive of local control (odds ratio: 1.34, 95% confidence interval: 1.06-1.70). Area under the receiver operating characteristic curve for local control and mean dose by volume was 0.6199 with a threshold of 2.05 Gy/mm (local failure 7.6% above and 17.3% below 2.05 Gy/mm). Conclusion: A dose–volume response relationship exists for brain metastases treated with robotic stereotactic radiosurgery. Mean dose per volume is strongly predictive of local control and can be potentially useful during stereotactic radiosurgery plan evaluation while respecting previously established dose constraints.

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Herein, András, Gábor Stelczer, Csilla Pesznyák, Georgina Fröhlich, Viktor Smanykó, Norbert Mészáros, Csaba Polgár und Tibor Major. „Multicatheter interstitial brachytherapy versus stereotactic radiotherapy with CyberKnife for accelerated partial breast irradiation: a comparative treatment planning study with respect to dosimetry of organs at risk“. Radiology and Oncology 55, Nr. 2 (25.03.2021): 229–39. http://dx.doi.org/10.2478/raon-2021-0016.

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Abstract Background The aim of the study was to dosimetrically compare multicatheter interstitial brachytherapy (MIBT) and stereotactic radiotherapy with CyberKnife (CK) for accelerated partial breast irradiation (APBI) especially concerning the dose of organs at risk (OAR-s). Patients and methods Treatment plans of thirty-two MIBT and CK patients were compared. The OAR-s included ipsilateral non-target and contralateral breast, ipsilateral and contralateral lung, skin, ribs, and heart for left-sided cases. The fractionation was identical (4 x 6.25 Gy) in both treatment groups. The relative volumes (e.g. V100, V90) receiving a given relative dose (100%, 90%), and the relative doses (e.g. D0.1cm3, D1cm3) delivered to the most exposed small volumes (0.1 cm3, 1 cm3) were calculated from dose-volume histograms. All dose values were related to the prescribed dose (25 Gy). Results Regarding non-target breast CK performed slightly better than MIBT (V100: 0.7% vs. 1.6%, V50: 10.5% vs. 12.9%). The mean dose of the ipsilateral lung was the same for both techniques (4.9%), but doses irradiated to volume of 1 cm3 were lower with MIBT (36.1% vs. 45.4%). Protection of skin and rib was better with MIBT. There were no significant differences between the dose-volume parameters of the heart, but with MIBT, slightly larger volumes were irradiated by 5% dose (V5: 29.9% vs. 21.2%). Contralateral breast and lung received a somewhat higher dose with MIBT (D1cm3: 2.6% vs. 1.8% and 3.6% vs. 2.5%). Conclusions The target volume can be properly irradiated by both techniques with similar dose distributions and high dose conformity. Regarding the dose to the non-target breast, heart, and contralateral organs the CK was superior, but the nearby organs (skin, ribs, ipsilateral lung) received less dose with MIBT. The observed dosimetric differences were small but significant in a few parameters at the examined patient number. More studies are needed to explore whether these dosimetric findings have clinical significance.

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Fiorino, C., C. Cozzarini, G. Sanguineti, V. Vavassori, C. Bianchi, F. Foppiano, A. Magli, A. Piazzolla und G. M. Cattaneo. „Correlation between dose-volume constraints and late rectum bleeding in patients treated for prostate cancer at dose between 70 and 76 Gy“. International Journal of Radiation Oncology*Biology*Physics 51, Nr. 3 (November 2001): 141. http://dx.doi.org/10.1016/s0360-3016(01)02079-x.

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Thorsen, F. A., und J. C. Ganz. „Dose Planning with the Leksell Gamma Knife: The Effect on Dose Volume of More Than One Shot at the Same Target Point“. Stereotactic and Functional Neurosurgery 61, Nr. 1 (1993): 151–63. http://dx.doi.org/10.1159/000100669.

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Harmon, Grant, Bonnie Chinsky, Murat Surucu und William Small. „Effect of Bladder Distension on Dosimetry of Organs at Risk During Intracavitary Cervical HDR Brachytherapy Using Dose-Volume and Dose-Surface Histograms“. Brachytherapy 14 (Mai 2015): S77—S78. http://dx.doi.org/10.1016/j.brachy.2015.02.328.

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Patel, Shyamal, Keyur J. Mehta, Hsiang-Chi G. Kuo, Nitin Ohri, Rajal Patel, Ravi Yaparpalvi, Madhur K. Garg, Chandan Guha und Shalom Kalnicki. „Do changes in interfraction organ at risk volume and cylinder insertion geometry impact delivered dose in high-dose-rate vaginal cuff brachytherapy?“ Brachytherapy 15, Nr. 2 (März 2016): 185–90. http://dx.doi.org/10.1016/j.brachy.2015.11.004.

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Tharavichitkul, Ekkasit, Somvilai Chakrabandhu, Pitchayaponne Klunklin, Wimrak Onchan, Bongkot Jia-Mahasap, Suwapim Janla-or, Damrongsak Tippanya et al. „Five-year results for image-guided brachytherapy (IGBT) for cervical carcinoma: a report from single institute of Thailand“. Journal of Radiotherapy in Practice 16, Nr. 1 (21.12.2016): 38–45. http://dx.doi.org/10.1017/s1460396916000510.

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AbstractAimTo report of long-term results and toxicity profiles using image-guided brachytherapy (IGBT) combined with whole pelvic radiation therapy (WPRT) for cervical carcinoma.Materials and MethodsIn total, 52 patients with locally advanced cervical carcinoma were enrolled into the study. WPRT was used to treat the clinical target volume (CTV) with a dose of 45–50·4 Gy in 23–28 fractions. IGBT using computed tomography was performed at the dose of 6·5–7 Gy×4 fractions to the minimum dose covering 90% of target volume (D90) of high-risk clinical target volume (HR-CTV).ResultsThe mean cumulative dose in equivalent doses of 2 Gy for the D90 of HR-CTV, dose at 2% at refereed volume (D2cc) of bladder, D2cc of rectum and D2cc of sigmoid colon were 92·4, 87·9, 69·6, and 72 Gy, respectively. At the median follow-up time of 61 months, the 5-year local control, disease-free survival, and overall survival rates were 96·2, 75 and 84·6% respectively. Two patients (3·8%) developed grade 3–4 gastrointestinal and two patients (3·8%) developed grade 3–4 genitourinal toxicities.ConclusionThe combination of WPRT plus IGBT showed very promising long-term results with excellent local control and toxicity profiles.

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Klisarovska, Violeta, Snezhana Smichkoska, Petar Chakalaroski, Valentina Krstevska, Nadica Dimitrovska, Zoran Stefanovski und Emilija Lazarova. „Dosimetric comparison of two-dimensional versus three-dimensional intracavitary brachytherapy in locally advanced cervical cancer“. Srpski arhiv za celokupno lekarstvo 146, Nr. 3-4 (2018): 157–62. http://dx.doi.org/10.2298/sarh170301160k.

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Introduction/Objective. The aim of this study was to dosimetric comparison of two-dimensional (2D) with three-dimensional (3D) planning for high-dose-rate intracavitary brachytherapy (HDR-BT) in locally advanced cervical cancer by dose evaluation in given International Commission on Radiation Units and Measurements (ICRU) reference points, as well as in target volume and organs at risk (OAR). Methods. 66 sessions of HDR-BT were performed in 22 patients, with 3D planning, but also virtual 2D plan for dosimetric comparison was made. 2D planning was performed on radiography obtained by C-arm in ICRU points, while 3D planning in volumes delineated on computer tomography. Results. The comparative analysis has indicated a significant mean dose difference of point ?A? left (p=0.00014) and right (p=0.003), through higher doses in 2D and lower doses in 3D reconstructed points "A". According to the dose volume histograms 56.88% and 61.41% mean target volume received 100% and 90% of prescribed dose, respectively. 2D bladder analysis showed a mean dose of 3.487 Gy in ICRU point, while in 3D analysis a maximum mean dose of 8.804 Gy and mean dose of 4.716 Gy in 2ccm volume. 2D analysis showed rectal mean dose of 2.892 Gy in ICRU points, while 3D analysis maximum mean dose of 6.411 Gy and 3.947 Gy mean dose in 2ccm volume. Conclusion. 2D planning showed unreal higher doses in the ICRU points for the target and lower doses for the OAR.

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Hudgins, W. Robert, Kyle J. Antes, Morley A. Herbert, Richard L. Weiner, J. Michael Desaloms, Denise Stamos, Jerry L. Barker, Gregory A. Echt, Timothy D. Nichols und Donald E. Schwarz. „Control of growth of vestibular schwannomas with low-dose Gamma Knife surgery“. Journal of Neurosurgery 105, Supplement (Dezember 2006): 154–60. http://dx.doi.org/10.3171/sup.2006.105.7.154.

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ObjectThe treatment of solitary vestibular schwannomas by performing Gamma Knife surgery is well established. It has been reported that decreasing the surface dose reduces patient morbidity, especially facial weakness and numbness. The authors of this retrospective study examine patient data from a single center to determine if low-dose (≤ 14 Gy) GKS controls tumor growth as effectively as higher doses (> 14 Gy).MethodsBased on the formula for ellipsoid volumes, the tumor volumes were calculated using measurements from MR images obtained at follow up in patients treated at the authors' center. Follow-up data were available in 159 patients with a mean age of 59.5 ± 14.2 years at treatment. Fifty-six percent of the patients were women and 53.5% of the tumors were located on the right side of the brain. The mean tumor volume was 3.3 ± 4.3 cm3 with 10% of the tumors having volumes larger than 8 cm3. After GKS, smaller tumors (≥ 40% decrease in volume) were observed in 44.8% of patients treated with a low dose and in 48.8% treated with a high dose. Enlarged tumors (≥ 40% increase in volume) were seen in 5.2% of the patients receiving a low dose and 2.3% of those receiving a high dose. These differences were not statistically significant.Patients who had been followed up for longer than 5 years after treatment had median residual volumes of only 28.2% of the starting volume in the low-dose group and 26% in the high-dose group. This difference was statistically not significant.Conclusions No statistically significant differences were observed between tumors given low-dose radiation treatment and those given high-dose radiation treatment.

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Souweidane, Mark M., Kim Kramer, Neeta Pandit-Taskar, Zhiping Zhou, Pat Zanzonico, Maria Donzelli, Serge K. Lyashchenko et al. „A phase I study of convection-enhanced delivery of 124I-8H9 radio-labeled monoclonal antibody in children with diffuse intrinsic pontine glioma: An update with dose-response assessment.“ Journal of Clinical Oncology 37, Nr. 15_suppl (20.05.2019): 2008. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.2008.

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2008 Background: Diffuse intrinsic pontine glioma (DIPG) represents one of the most deadly central nervous system tumors of childhood with a median survival of less than 12 months. Convection-enhanced delivery (CED) has been recently hypothesized as a means for efficiently distributing therapeutic agents within the brain stem. We conducted this study to evaluate CED in children with DIPG. Methods: We performed a standard phase I dose escalation study in patients with non-progressive DIPG 4 to 14 weeks post-completion of radiation therapy. Seven dose levels of a single injection of 124I-8H9 (Omburtamab) (range 0.25 to 4.0 mCi) were studied. Results: 37 children were treated with 34 evaluable for primary and secondary endpoints. The median age at enrollment was 6.8 years old (range 3.2 - 17.9). There was no dose limiting toxicity (DLT). Among adverse events that were at least possibly related to the treatment, there were no grade 4 or 5 events, and only 4 reversible grade 3 events in 4 patients (2 hemiparesis, 1 skin infection and 1 anxiety). Estimations of distribution volumes based on T2-weighted imaging were dose dependent and ranged from 1.5 to 20.8 cm3, and for dose level 7, 10.5 - 19.0 cm3. The mean volume of distribution/volume of infusion ratio (Vd/Vi) was 3.4 ±1.1, and for dose level 7, 3.5 ± 1.0. The mean lesion absorbed dose was 33.3 ± 25.9 Gy, and for dose level 7, 50.1 ± 22.9 Gy. The mean ratio of lesion-to-whole body absorbed dose was 910. The mean volume of distribution/tumor volume ratio on dose level 7 was 82.5%, but the mean tumor overlap was 40.5%. No death occurred as a result of the treatment. Median survival was 15.3 months (n = 29, 95% CI 12.7 - 17.4). Median follow-up time of the 5 surviving patients is 27.2 months (range 11.5 - 72.4). Overall survival rate at 12 months was 64.7% (22/34, 4 alive), and overall survival rate at 24 months 14.7% (5/34, 3 alive). Conclusions: CED in the brain stem of children with DIPG who were previously irradiated is a safe therapeutic strategy. An infusion volume of 4,000 mcl appears to be a reasonable single dose for a target distribution volume but enhanced tumor coverage is likely needed. There seems to be a survival benefit using this therapeutic strategy and outcomes might be dependent on dosimetry and distribution patterns. Clinical trial information: NCT01502917.

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Maduell, Francisco. „Is There an ‘Optimal Dose' of Hemodiafiltration?“ Blood Purification 40, Suppl. 1 (2015): 17–23. http://dx.doi.org/10.1159/000437409.

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Background: Retrospective randomized clinical studies have shown that online hemodiafiltration (OL-HDF) is associated with a lower risk reduction of mortality than standard hemodialysis. Summary: In all of these large randomized studies, the convective volume seemed to be an important issue, but the optimal OL-HDF dose has not yet been defined. This article, to make a EUDIAL working group position, reviews the association between survival and convective volume, the minimum recommended replacement volume, the importance of the infusion flow rate, and the main limiting factors in achieving a high convective volume. Finally, the article discusses whether the convective dose should be normalized to body size. Key Messages: At present, there is sufficient scientific evidence to indicate that OL-HDF treatment reduces mortality risk and that it should be the first-line option in hemodialysis patients. It seems reasonable to recommend that patients should receive the highest possible convective dose and that the largest possible blood flow should be used to obtain the highest possible infusion flow rate. Based on the results of secondary analyses of the main clinical trials, the current recommendation of the optimal dose of OL-HDF, in the postdilutional mode and on a thrice-weekly treatment schedule, would be a convective volume higher than 23 liters/session. There is insufficient scientific evidence to recommend that the convective dose should be normalized to body size.

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Kazama, Tomiei, Kazuyuki Ikeda, Koji Morita, Takehiko Ikeda, Mutsuhito Kikura und Shigehito Sato. „Relation between Initial Blood Distribution Volume and Propofol Induction Dose Requirement“. Anesthesiology 94, Nr. 2 (01.02.2001): 205–10. http://dx.doi.org/10.1097/00000542-200102000-00007.

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Background Propofol induction dose is variable and depends on many factors, including initial volume of distribution and early disposition. The authors hypothesized that preadministration blood distribution volumes, cardiac output (CO), and hepatic blood flow (HBF) could be examined to establish a propofol induction dose. Methods Propofol dose required to reach loss of consciousness, when infused at infusion rate per lean body mass (LBM) of 40 mg x kg(-1) x h(-1), was determined in 75 patients aged 11-85 yr. CO, blood volume (BV), central blood volume (CBV), and HBF were measured with indocyanine green pulse spectrophotometry. Univariate least squares linear regression analysis was used to individually analyze the relation between propofol induction dose and patient characteristics, including LBM, baseline distribution volumes, CO, and HBF. Stepwise multiple linear regression models were used to select important predictors of induction dose. Results Although there was a significant correlation between the induction dose and each of the eight variables of age, sex, LBM, hemoglobin, CO, BV, CBV, and HBF, only factors of age (partial r = -0.655), LBM (partial r = 0.325), CBV (partial r = 0.540), and HBF (partial r = 0.357) were independently associated with the induction dose (R2 = 0.85) when all variables were included in a multivariate model. Conclusions At a constant propofol infusion rate of 40 mg x kg(-1) x h(-1) as a function of LBM in patients with American Society of Anesthesiologists physical status I or II, the induction dose can be determined from four variables: age, LBM, CBV, and HBF.

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Wilke, L., C. Moustakis, O. Blanck, D. Albers, C. Albrecht, Y. Avcu, R. Boucenna et al. „Improving interinstitutional and intertechnology consistency of pulmonary SBRT by dose prescription to the mean internal target volume dose“. Strahlentherapie und Onkologie 197, Nr. 9 (01.07.2021): 836–46. http://dx.doi.org/10.1007/s00066-021-01799-w.

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Abstract Purpose Dose, fractionation, normalization and the dose profile inside the target volume vary substantially in pulmonary stereotactic body radiotherapy (SBRT) between different institutions and SBRT technologies. Published planning studies have shown large variations of the mean dose in planning target volume (PTV) and gross tumor volume (GTV) or internal target volume (ITV) when dose prescription is performed to the PTV covering isodose. This planning study investigated whether dose prescription to the mean dose of the ITV improves consistency in pulmonary SBRT dose distributions. Materials and methods This was a multi-institutional planning study by the German Society of Radiation Oncology (DEGRO) working group Radiosurgery and Stereotactic Radiotherapy. CT images and structures of ITV, PTV and all relevant organs at risk (OAR) for two patients with early stage non-small cell lung cancer (NSCLC) were distributed to all participating institutions. Each institute created a treatment plan with the technique commonly used in the institute for lung SBRT. The specified dose fractionation was 3 × 21.5 Gy normalized to the mean ITV dose. Additional dose objectives for target volumes and OAR were provided. Results In all, 52 plans from 25 institutions were included in this analysis: 8 robotic radiosurgery (RRS), 34 intensity-modulated (MOD), and 10 3D-conformal (3D) radiation therapy plans. The distribution of the mean dose in the PTV did not differ significantly between the two patients (median 56.9 Gy vs 56.6 Gy). There was only a small difference between the techniques, with RRS having the lowest mean PTV dose with a median of 55.9 Gy followed by MOD plans with 56.7 Gy and 3D plans with 57.4 Gy having the highest. For the different organs at risk no significant difference between the techniques could be found. Conclusions This planning study pointed out that multiparameter dose prescription including normalization on the mean ITV dose in combination with detailed objectives for the PTV and ITV achieve consistent dose distributions for peripheral lung tumors in combination with an ITV concept between different delivery techniques and across institutions.

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Haycocks, T., J. Mui, H. Alasti und C. Catton. „Dose volume histogram analysis for organs at risk when using 6 external beam techniques for radical prostatic irradiation“. Journal of Radiotherapy in Practice 2, Nr. 1 (März 2000): 17–25. http://dx.doi.org/10.1017/s1460396900000042.

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Ten patients with prostate cancer were each planned with 3 conventional and 3 conformal isocentric treatment techniques to compare the relative radiation doses to the bladder and rectal walls, and femoral head using dose volume histograms (DVH). The DVH were calculated for each organ and each technique, and the plans were ranked using the area under the curve method and also by the relative radiation dose given to specific normal tissue volumes.The results show that for the planning target volume chosen, the 4 field non-coplanar technique delivers the least dose to the bladder, the 6 field coplanar technique delivers the least dose to the rectum and the 3 field oblique technique delivers the least dose to the femoral heads. The 4-field technique with no shielding contributes the most dose to the bladder and rectum and the 6 field coplanar technique contributes the most dose to the femoral heads.No technique was shown to be optimal for all the organs at risk, but both the 6 field and 4 field non-coplanar field arrangements were shown to be superior techniques for minimising both the bladder and rectal dosage. The choice of technique will therefore depend on other factors such as the total prescribed dose, the ease of set-up and the ease of verification of isocentre reproducibility.

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