Open AccessEnergy dependence and angular dependence of an optically stimulated luminescence dosimeter in the mammography energy range
Author(s) -
Kawaguchi Ai,
Matsunaga Yuta,
Suzuki Shoichi,
Chida Koichi
Publication year - 2017
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.12041
Subject(s) - dosimeter , materials science , atomic physics , range (aeronautics) , optically stimulated luminescence , analytical chemistry (journal) , luminescence , half value layer , optics , physics , chemistry , radiation , optoelectronics , chromatography , composite material , radiation shielding
Abstract This study aimed to investigate the energy dependence and the angular dependence of commercially available optically stimulated luminescence ( OSL ) point dosimeters in the mammography energy range. The energy dependence was evaluated to calculate calibration factors ( CF s). The half‐value layer range was 0.31–0.60 mmAl (Mo/Mo 22–28 kV , Mo/Rh 28–32 kV , and W/Rh 30–34 kV at 2‐ kV intervals). Mo/Rh 28 kV was the reference condition. Angular dependence was tested by rotating the X‐ray tube from −90° to 90° in 30° increments, and signal counts from angled nanoDots were normalized to the 0° signal counts. Angular dependence was compared with three tube voltage and target/filter combinations (Mo/Mo 26 kV , Mo/Rh 28 kV and W/Rh 32 kV ). The CF s of energy dependence were 0.94–1.06. In Mo/Mo 26–28 kV and Mo/Rh 28–32 kV , the range of CF was 0.99–1.01, which was very similar. For angular dependence, the most deteriorated normalized values (Mo/Mo, 0.37; Mo/Rh, 0.43; and W/Rh, 0.58) were observed when the X‐ray tube was rotated at a 90° angle, compared to 0°. The most angular dependences of ± 30°, 60°, and 90° decreased by approximately 4%, 14%, and 63% respectively. The mean deteriorated measurement 30° intervals from 0° to ± 30° was 2%, from ± 30° to ± 60° was 8%, and from ± 60° to ± 90° was 40%. The range of energy dependence in typical mammography energy range was not as much as that in general radiography and computed tomography. For accurate measurement using nanoDot, the tilt needs to be under 30°.