Development of Inclined Applicators for Flattened Beam Intraoperative Radiotherapy

Abstract Purpose: We introduce a 3D-printed applicator for Intraoperative Radiation Therapy (IORT) using the INTRABEAM system. The applicator is designed to spare normal tissue, increase indications, and evaluate its clinical use in various intraoperative cases. Methods: We designed and fabricated inclined applicators at 0° and 45° to generate flattened and unflattened beams and shield leakage dose to non-target regions. We evaluated the characteristics of the applicator, including dose uniformity, percentage depth dose, leakage, and dose rate of the beam. Results: The uniformity of developed applicators at depths of 0, 2, 5, and 15 mm were as follows: 1.23, 1.28, 1.30, and 1.22 for a flattened beam, and 1.29, 1.32, 1.27, and 1.25 for an unflattened beam, respectively. No leakage dose was measured at a distance of 1 mm from the surface, and the measured dose rates after 3 min of irradiation for the flattened and unflattened beams of the 0° and 45° applicators were 51.0 and 52.9 cGy and 48.5 and 54.8 cGy, respectively. Conclusions: The developed applicator demonstrated a uniform beam and leakage shielding to minimize radiation exposure to normal tissue. Customized applicators facilitated IORT treatment of chest and abdominal lesions near or on critical organs. The proposed method has been dose calibrated, and we proceeded with clinical application.