160b Clinical in vivo dosimetry using optical radiation sensor fibers

Abstract

Purpose As our previously reported basic investigations indicated, optical loss in silica induced by ionizing radiation may be used for dosimetrical purposes. We tested a novel optical fiber radiation sensor in clinical settings. Methods A lead doped silica fiber (diam ≤ 0.5 mm, L≈, 0.6 m) was rolled up to a circle (diam ≈ 15 mm). This ring sensor was put on the closed eye lid during orbital irradiation in order to estimate the surface dose (SD) close to the eye lens due to scattered radiation. Patients were treated with bilateral parallel opposed fields (8 MV x-rays, size ≈ 4 × 4 cm2) by reason of Graves’ disease, uvea metastases and nasopharynx carcinoma. Results We were able to detenuine the SD in all patients in real time. Results are compared with phantom measurements using TLD. Conclusions Optical fiber sensors are suitable for clinical in vivo dosimetry. They may become a valuable tool in quality assurance, IORT and conformal therapy. Other applications are discussed.