Academic literature on the topic 'Iodine-125 radioactive seeds'

Aims and background Brachytherapy for prostate cancer by means of permanently implanted 125 I sources is a well established procedure. An increasing number of patients all over the world are treated with this modality. When the technique was introduced at our institution, radiation protection issues relative to this technique were investigated in order to comply with international recommendations and national regulations. Particular attention was paid to the need for patient shielding after discharge from hospital. Methods The effective and equivalent doses to personnel related to implantation, the effective dose to patient relatives as computed by a developed algorithm, the air kerma strength values for the radioactive sources certified by the manufacturer compared with those measured by a well chamber, and the effectiveness of lead gloves in shielding the hands were evaluated. Results The effective dose to the bodies of personnel protected by a lead apron proved to be negligible. The mean equivalent doses to the physician's hands was 420 μSv for one implant; the technician's hands received 65 μSv. The mean air kerma rate measured at the anterior skin surface of the patient who had received an implant was 55 μGy/h (range, 10–115) and was negligible with lead protection. The measured and certified air kerma strength for 125I seeds in RAPID Strand corresponded within a margin of ± 5%. The measured attenuation by lead gloves in operative conditions was about 80%. We also defined the recommendations to be given to the patient at discharge. Conclusions The exposure risks related to brachytherapy with 125I to operators and public are limited. However, alternation of operators should be considered to minimize exposure. Patient-related measurements should verify the dose rate around the patient to evaluate the need for shielding and to define appropriate radiation protection recommendations.

Merkel cell carcinoma is a rapidly progressive nonmelanoma skin cancer with a high risk of recurrence. When recurrence occurs, it is associated with poor prognosis and there is a lack of guidelines for the management of such cases. This article describes a challenging case in which the innovative use of iodine-125 radioactive seeds permitted us to precisely identify and resect two nonpalpable recurrent nodules. The safety and accuracy of the surgical procedure were compromised by the presence of scar tissue following two past resections and two courses of radiotherapy. Radioactive seed localization is a well-known procedure in breast cancer, demonstrating potential for an extended application in other cancer types and in complex clinical situations.

We aimed to evaluate the surgical margin outcomes and re-excision rates in patients undergoing bracketed seed localization of biopsy-proven breast cancer detected on screening mammogram. After approval by our Institutional Review Board, we retrospectively identified patients who had undergone iodine-125 seed localized lumpectomy at our institution from January 2010 to June 2017 by one of two fellowship-trained breast surgeons. Of those patients, a subset of 25 patients were identified who had undergone bracketed seed localization, defined as two or more seeds used to delineate the radiographic borders of the area of concern. All patients had originally presented with calcifications identified on screening mammogram that were subsequently diagnosed as ductal carcinoma in situ and/or invasive ductal carcinoma by image-guided biopsy performed at our institution. Eight patients had one positive margin on final surgical pathology and required re-excision (32%). One patient was converted to mastectomy. Of the patients requiring re-excision, the average maximum linear extent of calcifications was 3.4 cm (SD 0.97), whereas it was 3.1 cm (SD 1.2) in patients with negative surgical margins ( P = 0.5). Bracketing calcifications with radioactive seeds can potentially allow more patients to undergo breast conservation surgery.

Câncer é a segunda causa de morte no mundo e foi responsável por 8,8 milhões de mortes em 2015, de acordo com a Organização Mundial da Saúde (OMS). Segundo o Instituto Nacional do Câncer (INCA), essa doença é um problema de utilidade pública. Em valores absolutos, o câncer de próstata, neoplasia maligna mais comum entre os homens, é o sexto tipo mais comum no mundo. Dentre os tratamentos para câncer de próstata estão a cirurgia, quimioterapia e radioterapia. Um dos principais tipos de radioterapia é a braquiterapia, realizada por meio de sementes radioativas de iodo-125, que são inseridas na próstata do paciente e liberam pequenas doses de radiação. Essas sementes podem ser introduzidas soltas ou em cordas poliméricas Quando introduzidas soltas, de acordo com a literatura, essas sementes podem migrar para outros órgãos. Para evitar essa migração, usa-se as sementes em cordas poliméricas. As cordas poliméricas são constituídas pelo poli(ácido lático-co-ácido glicólico), PLGA. O PLGA pode ser obtido por meio de seus dímeros cíclicos: glicolídeo e lactídeo. Esses dímeros, por sua vez, podem ser produzidos a partir de seus respectivos monômeros, os ácidos glicólico e lático. O objetivo desse trabalho foi analisar e discutir as condições favoráveis à síntese dos dímeros glicolídeo e lactídeo, dentre elas, etapas do processo e valores de temperatura e pressão. Foram executados sete experimentos com diferentes temperaturas e pressões nas três etapas da síntese: desidratação do ácido, formação do pré-polímero e despolimerização do pré-polímero. Na etapa intermediária da síntese, foi obtido o PLA quando foram utilizadas temperaturas acima de 150°C. A etapa final mostrou que temperaturas abaixo de 200°C não formam os dímeros.
Cancer is the second leading cause of world death and it was responsible for 8.8 million deaths in 2015, according to the World Health Organization (WHO). According to the National Cancer Institute (INCA), this disease is a public utility problem. In absolute values, prostate cancer, the most common cancer among men, is the sixth most common type in the world. Among prostate cancer treatments are surgery, chemotherapy and radiotherapy. One of the main radiotherapy types is brachytherapy, performed by iodine-125 radioactive seeds, which are inserted into the patient\'s prostate and release small radiation doses. These seeds can be introduced loose or such as stranded seeds. When introduced such as loose seeds, according to literature, these seeds can migrate to other organs. In order to avoid this migration, it is used stranded seeds. The stranded seeds are composed of PLGA, poly(lactic acid-co-glycolic acid). PLGA can be obtained by its cyclic dimers: glycolide and lactide. These dimers can be produced from their respective monomers, glycolic and lactic acids. The purpose of this study was to analyze and discuss the favorable conditions of the glycolide and lactide synthesis, such as process steps and temperature and pressure values. Seven experiments were performed at different temperatures and pressures in three synthesis steps: acid dehydration, prepolymer formation and depolymerization of prepolymer. In intermediary step, the PLA was obtained when temperatures were above 150°C. The final step showed that dimers are not formed at temperatures below 200°C.

Radiation products are present in several fields of knowledge. From the energy field, with nuclear reactors and nuclear batteries, to the medical field, with nuclear medicine and radiation therapy (brachytherapy). Although chemistry works in the same way for radioactive and non-radioactive chemicals, an extra layer of problems is present in the radiochemical counter-part. Reactions can be unpredictable due to several factors. For example, iodine-125 in deposited in a silver wire to create the core of a medical radioactive seed. This core is the sealed forming a radioactive seed that are placed inside the cancer. Several aspects can be discussed in regards to radiation chemistry. For example: are there any competing ions? Each way my reaction is going? Each reaction is more likely to occur? Those are important questions, because, in the case of iodine, a volatile product can be formed causing contamination of laboratory, equipment, personal, and environment. This chapter attempts to create a guideline on how to safely proceed when a new radioactive chemical reaction. It discusses the steps by giving practical examples. The focus is in protecting the operator and the environment. The result can be achieved safely and be reliable contribution to science and society.