Characterization of Small Dosimeters Used for Measurement of Eye Lens Dose for Medical Staff during Fluoroscopic Examination.

Kosuke Matsubara,Thunyarat Chusin,Yasushi Furukawa,Ayaka Hirosawa,Sayu Yoshida

doi:10.3390/diagnostics11020150

Abstract

This study aimed to evaluate the property of small dosimeters used for measuring eye lens doses for medical staff during fluoroscopic examination. Dose linearity, energy dependence, and directional dependence of scattered X-rays were evaluated for small radiophotoluminescence glass dosimeters (RPLDs), those with a tin filter (Sn-RPLDs), and small optically stimulated luminescence dosimeters (OSLDs). These dosimeters were pasted on radioprotective glasses, and accumulated air kerma was obtained after irradiating the X-rays to a patient phantom. Strong correlations existed between fluoroscopic time and accumulated air kerma in all types of dosimeters. The energy dependence of Sn-RPLD and OSLD was smaller than that of RPLD. The relative dose value of the OSLD gradually decreased as the angle of the OSLD against the scattered X-rays was larger or lower than the right angle in the horizontal direction. The ranges of relative dose values of RPLD and Sn-RPLD were larger than that of OSLD in the vertical direction. The OSLDs showed lower doses than the RPLDs and Sn-RPLDs, especially on the right side of the radioprotective glasses. These results showed that RPLDs, Sn-RPLDs, and OSLDs had different dosimeter properties, and influence measured eye lens doses for the physician, especially on the opposite side of the patient.

Highlights

optically stimulated luminescence dosimeters (OSLDs), strong correlations fourfour times greater than that by the Sn-radiophotoluminescence glass dosimeters (RPLDs) and OSLDs, correlations were noted between fluoroscopic time and accumulated air kermaair measured by RPLDs by RPLDs were noted between fluoroscopic time and accumulated kerma measured
The results of this study indicated that RPLDs, Sn-RPLDs, and OSLDs had different dosimeter properties, and affected the measured values of eye lens doses for the physician phantom during the fluoroscopic examination
Previous studies showed that the response of RPLD, Sn-RPLD, and OSLD yielded a linear proportion to the radiation dose [12,17,18], and the current study indicated similar linear correlations between fluoroscopic time and air kerma accumulated from scattered

Summary

Introduction

Occupational dose limits are set to protect workers from the effects of ionizing radiation. The increased use of therapeutic and diagnostic radiology procedures results in larger doses for medical staff. Individual monitoring of external radiation is essential in assessing occupational exposure. A new threshold dose of 0.5 Gy was suggested by the International Commission on Radiological Protection (ICRP) in 2011 for radiation effects on the eye lens, which is a highly radiosensitive tissue. The ICRP recommended a new occupational equivalent dose limit for the eye lens of 20 mSv/year, averaged over defined periods of five years, with no single year exceeding 50 mSv [1]. The International Atomic Energy Agency (IAEA) adopted the occupational dose limit for the

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