Estimated radiation doses to ovarian and uterine organs in breast cancer irradiation using radio-photoluminescent glass dosimeters (RPLDs)

Abstract

Introduction: The well-being of breast cancer patients is essential, especially fertility in patients of reproductive age. The objective of this study was to estimate the radiation doses to the ovaries and uterus for different treatment techniques of breast cancer irradiation using radio-photoluminescent glass dosimeters (RPLDs). Methods: A Farmer-type ionisation chamber (IBA FC-65G) and RPLDs were used to measure in- and out-of-field radiation doses in a solid water phantom. The field sizes were set to 10 × 10 cm2 and 8 × 17 cm2 with the central axis at out-of-field measurement distances of 30 or 50 cm. The Rando phantom’s left breast was planned using four different techniques: two tangential standard fields with and without electronic tissue compensator (E-comp) techniques, intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). The radiation doses in the ipsilateral ovary, contralateral ovary and uterus were measured using RPLDs. Results: The percentage ratio of out of field to in field was affected by distance from the central axis to the point of measurement, in addition to the field sizes associated with collimator scatter. Advanced techniques such as IMRT and VMAT produced higher doses to the ovaries and uterus. The estimated results of the worst-case scenario for the ipsilateral ovary, contralateral ovary and uterus were 0.84% (42 cGy), 0.62% (31 cGy) and 0.76% (38 cGy), respectively, for a 5000 cGy prescription dose. Conclusion: The lowest to highest out-of-field radiation doses to the ovarian and uterine organs from breast irradiation were the two tangential field techniques, VMAT and IMRT. These advanced techniques yielded higher radiation leakage, which potentially contributed to the out-of-field radiation dose.