Médecine Nucléaire et Radiothérapie

No standard salvage therapy exists. The objective of salvage therapy is oncological control with minimum toxicity. Advances in functional imaging, including multi parametric prostate MRI and abdominopelvic lymphangio- MRI, have paved the way for salvage therapy in localised recurrence. To date there are no randomized clinical trials comparing HDR-BT with radical prostatectomy. Methods: We conduct as retrospective review over 20 years comparing outcomes of salvage brachytherapy compared to open and robotic radical prostatectomy, searching Embase and Medline. Results: Whilst robotic radical prostatectomy is a clear winner, there is also a role for salvage brachytherapy. Conclusions: The role of salvage therapies such as brachytherapy need to be further explored.

A survey taken by the world health organization (WHO) and the international commission on radiation protection (ICRP) shows that certain materials used for the construction of such buildings (rocks soils) are known to be radioactive. Exposure to indoor ionizing radiation like exposure to any other type of ionizing radiation results in critical health challenges. This work set out to determine the levels of background ionizing radiations in selected buildings around Nairobi County and its environs. The Radiation Alert R (Digilert 200) meters were used to capture the readings. The meters were held about 1 m above ground level and readings were recorded in mR/h for all buildings. Numerical data was subjected to analysis of variance using Minitab version 17.0 to determine the statistical differences of exposure levels within various areas. A total of 400 buildings were sampled. The annual indoor readings were highest in Eastleigh (4.070 mSv) and relatively lowest in Nairobi Central Business District (CBD) at 2.763 mSv, representing a deviation from WHO recommended standard of 307.0% and 176.3%, respectively. None of the buildings sampled had exposure levels below the WHO recommended standard of 1 mSv. Overall, these results indicate presence of higher levels of ionizing radiations in buildings beyond the acceptable annual threshold thereby posing significant health risk to the public. Consequently, these results could find great application in guiding the formulation of the national building code to include routine surveillance of the background ionizing radiation levels in various buildings to assess the health risk of general public as well as exploring appropriate mitigation approaches.

Radiation therapy using external beam radiation therapy (EBRT) is playing an important role for effective treatment of all kinds of tumors. Peripheral dose is the result of leakage and scatter from multileaf collimators devices (MLCs), counts for 2-10% of the maximum dose given to the patient, depending on the machine used and type of treatment. The present review reveals that despite of the recent advancements in linear accelerators (LINAC) and MLC design and technology, the remaining small amount of leakage (peripheral dose) of these devices still has significant side effects on patient’s life span and quality of life after treatment. Based on the findings in this review, it is suggested that introduction of additional effective and patient-specific shielding techniques would have great impact on reducing risk of radiating healthy cells and hence adversely side effects on cancer patients.

Abstract Objectives: The purpose of this study is to investigate the comparison of 3DVH software and two-dimensional array systems (MatriXX, ArcCHECK, and portal dosimetry system) on pretreatment verification for volumetricmodulated arc therapy. Methods: Dosimetric measurements were performed using the verification for 20 treatment plans. Measured dosimetric differences were evaluated by gamma pass rate and percentage dose difference. Dose-volume histograms (DVHs) calculated by the treatment planning system were also compared with those predicted by the 3DVH software. Results: The mean gamma pass rates were more than 95% for the 3%/3 mm criterion, except for 3D evaluation using the 3DVH (3DVH (3D)) software in prostate cancer cases. In the cases of head-and-neck (HN) cancer, the mean gamma pass rates by ArcCHECK and 3DVH 2D evaluation (3DVH (2D)) were estimated to be lower than those of MatriXX, EPID, and 3DVH (3D) for the 2%/2 mm and 1%/1 mm criteria. The percentage dose differences were within 4% for all structures, and correlated with the mean gamma pass rate for the planning target volume (PTV) and the Dmean of the spinal cord (p < 0.05). On the other hand, the mean gamma pass rates of prostate cases presented similar results for all criteria. The percentage dose differences for structure volumes in the cases of prostate cancer (from 2.76% to 12.58%) were larger than those in the cases of HN cancer, and there was no statistical significance except for the Dmax of the bladder. Conclusion: Judging from our results, the three dosimetric devices showed similar results for pretreatment verification and portal dosimetry can be replaced as the verification system. However, the use of 3DVH software remains to be a matter for further discussion.

Prostate cancer is the most common solid malignancy among men in the Western world. Of the 50% of patients with localized prostate cancer who elect to undergo radical prostatectomy, up to 60% will experience recurrence of disease. Salvage radiotherapy is the standard treatment for biochemically recurrent prostate cancer but rates of success in terms of long-term biochemical control remain suboptimal. Functional imaging may potentially improve salvage radiotherapy via detection of disease foci which would otherwise be missed by conventional imaging modalities. Herein we review the most commonly employed PET radiotracers for prostate cancer (11C-choline, 18F-choline, and 11C-acetate) with particular attention on their ability to identify foci of recurrent disease as well as their utility as a guide for radiotherapy.