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Measurement of peripheral dose to pelvic region and associated risk for cancer development after breast intraoperative electron radiation therapy
摘要： This study aimed to measure received dose to the pelvic region of patients during breast intraoperative electron radiation therapy (IOERT). Furthermore, we compared the findings with those of external beam radiation therapy. Finally, secondary ovary and uterus cancer risks following breast IOERT were estimated. In the current study, the received dose to the pelvic surface of 18 female patients during breast IOERT boost were measured by thermoluminescent dosimeter (TLD-100) chips. All patients were treated with 12 Gy given in a single fraction. To estimate the dose to the ovary and uterus of the patients, conversion coefficients for depth from surface dose were obtained in a Rando phantom. Given the received dose to the pelvic region of the patients, secondary ovary and uterus cancer risks following breast IOERT were estimated. The received doses to ovary and uterus surface of the patients were 0.260±0.155 mGy to 31.460±6.020 mGy and 0.485±0.122 mGy to 22.387±15.476 mGy, respectively. Corresponding intra-pelvic (ovary and uterus) regional doses were 0.012±0.007 mGy to 1.479±0.283 mGy and 0.027±0.001 mGy to 1.164±0.805 mGy, respectively. Findings demonstrated that the ratio of the received dose by pelvic surface to regional dose during breast IOERT was much less than external beam energies were 135.722±117.331 × 10-6 and 69.958±28.072 × 10-6, and for uterus were 17.342±10.583 × 10-6 and 2.971±3.604 × 10-6, respectively. According to our finding, the use of breast IOERT in pregnant patients can be considered as a safe radiotherapeutic technique, because the received dose to the fetus was lower than 50 mGy. Furthermore, IOERT can efficiently reduce the unnecessary dose to the pelvis region and lowers the risk of a secondary ovary and uterus cancer following breast irradiation.
关键词： Breast cancer,peripheral dose,Radiation therapy,IOERT,Secondary cancer risk,pelvic region
更新于2025-09-23 15:23:52
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Surface scanning for 3D dose calculation in intraoperative electron radiation therapy
摘要： Dose calculations in intraoperative electron radiation therapy (IOERT) rely on the conventional assumption of water-equivalent tissues at the applicator end, which defines a flat irradiation surface. However, the shape of the irradiation surface modifies the dose distribution. Our study explores, for the first time, the use of surface scanning methods for three-dimensional dose calculation of IOERT. Two different three-dimensional scanning technologies were evaluated in a simulated IOERT scenario: a tracked conoscopic holography sensor (ConoProbe) and a structured-light three-dimensional scanner (Artec). Dose distributions obtained from computed tomography studies of the surgical field (gold standard) were compared with those calculated under the conventional assumption or from pseudo-computed tomography studies based on surfaces. In the simulated IOERT scenario, the conventional assumption led to an average gamma pass rate of 39.9% for dose values greater than 10% (two configurations, with and without blood in the surgical field). Results improved when considering surfaces in the dose calculation (88.5% for ConoProbe and 92.9% for Artec). More accurate three-dimensional dose distributions were obtained when considering surfaces in the dose calculation of the simulated surgical field. The structured-light three-dimensional scanner provided the best results in terms of dose distributions. The findings obtained in this specific experimental setup warrant further research on surface scanning in the IOERT context owing to the clinical interest of improving the documentation of the actual IOERT scenario.
关键词： Intraoperative radiotherapy,Structured-light 3D scanner,IOERT,Dose distribution,Surface scanning,Conoscopic holography
更新于2025-09-04 15:30:14