Feasibility of dosimetric measurements using Al2O3:C OSL dosimeter during fluoroscopy-guided procedures

Abstract

This study investigated the feasibility of dosimetric measurements using Al2O3:C optically stimulated luminescence (OSL) dosimeters during fluoroscopy-guided procedures. The linearity and energy dependence of Al2O3:C OSL dosimeters were evaluated, and the air kerma rate at the operator’s position was measured. The response of Al2O3:C OSL dosimeters to short, repetitive irradiations was compared to that of long uninterrupted irradiation. The change in response of the Al2O3:C OSL dosimeter under automatic exposure rate control (AERC) was evaluated with the use of various thicknesses of polymethyl-methacrylate (PMMA) plates (15–30 cm). The Al2O3:C OSL dosimeters could detect 5 µGy and showed good linearity in doses of ≥10 µGy (R2: 0.997–0.999, p < 0.001). The relative response of the Al2O3:C OSL dosimeter normalised to that of 36.8 keV was 0.828–1.101 at the energies investigated (30.6–46.0 keV). The air kerma rate at the operator’s position was estimated to be 2.61–7.17 µGy min−1 depending on the heights representing different body parts. Repetitive short irradiations had no significant impact on the relative response of the Al2O3:C OSL dosimeters (p > 0.05). Despite a high energy dependence on the low energy beam used in fluoroscopy, the change in relative response of the Al2O3:C OSL dosimeter under AERC was within 5.7% depending on the thickness of the PMMA plates. Dosimetric measurement using Al2O3:C OSL dosimeters for patients and operators is feasible. However, one should be cautious about high standard deviations when measuring small doses of ≤20 µGy using Al2O3:C OSL dosimeters. It is essential to perform intensive bleaching before measuring very small doses to minimise pre-irradiation counts.

Modified design of x‐ray protective clothing to enhance radiation protection for interventional radiologists

“…The accuracy of the integrated KAP meter compared to an external KAP meter (KermaX plus DDP, model 120−131, IBA Dosimetry GmbH, Schwarzenbruck, Germany) was 90.8 ± 1.6%. Based on the preliminary experimental results, the target KAP value was determined as the value predicted that the reading of nanoDot inserted in the left ovary would increase by 60 counts 17 . After irradiation, all nanoDots were read three times, and the difference between the average of the pre‐ and post‐irradiation readings was considered to be the actual radiation dose.…”

“…During the calibration, the half‐value layer (HVL) of the 80 kVp beam was also measured using the reference dosimeter. Thereafter, the effective photon energy (keV) of the 80 kVp beam was calculated based on the National Institute of Standards and Technology (NIST) Standard Reference Database 126, 23 by the same method as described in a previous study 17 . The mass energy absorption coefficients of the air and various tissue types for the effective photon energy of the 80 kVp beam were also determined according to the NIST Standard Reference Database 126 23 …”

“…To measure the organ doses to the operator, an adult female anthropomorphic phantom (ATOM model 702-G; CIRS, Norfolk, VA) loaded with 126 nanoDots (Landauer Inc., Glenwood, IL) was used (Figure 1). [17][18][19] The operator phantom was placed on the table, which was 68 cm in height, and simulated an interventional radiologist of 163 cm in height. The operator phantom was positioned 30 cm caudal and 40 cm to the right of the beam centerline.…”

“…Three nanoDots and a reference dosimeter (Multi-Detector XR, MagicMax Universal, IBA Dosimetry GmbH) were suspended in the air at the beam center and 70 cm distant from the x-ray tube using a custommade device. 17 After the irradiation of approximately 25 mGy, the ratio of the reference dosimeter reading to the nanoDot reading was calculated. This calibration procedure was repeated three times, and the calibration factor was averaged.…”

“…Thereafter, the effective photon energy (keV) of the 80 kVp beam was calculated based on the National Institute of Standards and Technology (NIST) Standard Reference Database 126, 23 by the same method as described in a previous study. 17 The mass energy absorption coefficients of the air and various tissue types for the effective photon energy of the 80 kVp beam were also determined according to the NIST Standard Reference Database 126. 23 The organ dose was calculated by averaging the readings of nanoDots inserted in the specific organ, except for the bone marrow, bone surface, and skin doses.…”