Physics and imaging in radiation oncology · 2025
Comparison of online adaptation strategies for magnetic resonance guided prostate radiation therapy.
СтатьяНазвание и аннотация: Перевод пока не подготовлен
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Mansour Iymad R, Johnstone Chris D, Malkov Victor, Létourneau Daniel, Chung Peter, Tadic Tony, Winter Jeff D
Аннотация
BACKGROUND AND PURPOSE: MR-guided adaptive radiation therapy allows for daily plan adaptation to account for anatomical changes. Two common strategies are adapt-to-position (ATP), involving re-optimization based on isocenter shifts, and adapt-to-shape (ATS), involving full recontouring and reoptimization. This study provides a dosimetric comparison of ATP and ATS using accumulated dose.
MATERIALS AND METHODS: Dose accumulation was performed for 35 patients with prostate cancer treated on a 1.5 T MR-Linac. All patients received ATS-based treatment with either 30.0 Gy in 5 fractions (30.0/5) or 42.7 Gy in 7 fractions (42.7/7), using a 5 mm isotropic PTV margin. ATP plans were retrospectively simulated. For each fraction, dose was mapped to a reference image using deformable image registration and summed across fractions. Fractional and accumulated dose-volume histogram (DVH) metrics were compared between ATS and ATP and correlated with daily anatomical variation.
RESULTS: ATP and ATS achieved equivalent accumulated CTV D95 and D98 for both regimens. In the 30.0/5 cohort, small but statistically significant differences in OAR dose were observed: accumulated bladder D40 was 4 % lower for ATP (1.27 Gy; p = 0.0004), and rectum D50 was 1 % lower for ATP (0.40 Gy; p = 0.0008). Differences in rectum D1cc and bladder D5cc were not significant. In the 42.7/7 cohort, femur D5 was 3 % higher for ATP (0.83 Gy; p = 0.02); other differences were insignificant. Dosimetric differences across strategies correlated with interfraction motion.
CONCLUSION: ATP and ATS provided equivalent target coverage. OAR differences were statistically significant in some cases but remained within clinical tolerances, suggesting minimal clinical impact.
MATERIALS AND METHODS: Dose accumulation was performed for 35 patients with prostate cancer treated on a 1.5 T MR-Linac. All patients received ATS-based treatment with either 30.0 Gy in 5 fractions (30.0/5) or 42.7 Gy in 7 fractions (42.7/7), using a 5 mm isotropic PTV margin. ATP plans were retrospectively simulated. For each fraction, dose was mapped to a reference image using deformable image registration and summed across fractions. Fractional and accumulated dose-volume histogram (DVH) metrics were compared between ATS and ATP and correlated with daily anatomical variation.
RESULTS: ATP and ATS achieved equivalent accumulated CTV D95 and D98 for both regimens. In the 30.0/5 cohort, small but statistically significant differences in OAR dose were observed: accumulated bladder D40 was 4 % lower for ATP (1.27 Gy; p = 0.0004), and rectum D50 was 1 % lower for ATP (0.40 Gy; p = 0.0008). Differences in rectum D1cc and bladder D5cc were not significant. In the 42.7/7 cohort, femur D5 was 3 % higher for ATP (0.83 Gy; p = 0.02); other differences were insignificant. Dosimetric differences across strategies correlated with interfraction motion.
CONCLUSION: ATP and ATS provided equivalent target coverage. OAR differences were statistically significant in some cases but remained within clinical tolerances, suggesting minimal clinical impact.