乳房X線撮影装置の実情に応じた低エネルギー用線量計校正定数供給の必要性

• Published in: 日本放射線技術学会雑誌 Vol. 64; no. 8; pp. 915 - 921
• Main Authors: 松尾, 千尋, 橘, 昌幸, 赤坂, 勉
• Format: Journal Article
• Language: Japanese
• Published: 公益社団法人 日本放射線技術学会 2008
• Subjects: calibration coefficient; calibration field; mammography; quality index-value
• ISSN: 0369-4305; 1881-4883
• DOI: 10.6009/jjrt.64.915

The calibration coefficient currently supplied by the National Institute of Advanced Industrial Science and Technology (AIST) is measured with an X-ray unit equipped with a W target/Al filter. We compared the calibration coefficient, which is measured with the X-ray unit equipped with a W target/Al filter and the X-ray unit for mammography. For the calibration coefficient, which is measured at the calibration fields of the X-ray units for mammography, the difference in the calibration coefficient measured with the X-ray unit equipped with a W target/Al filter that assumed a difference in the quality index-value of less than 1.5% was 24.2% at the maximum. In addition, many differences of more than unsureness 5% of the calibration coefficient were accepted. Thus, the correct dosimetry is not being performed for mammography. To improve the precision of dosimetry for mammography, at least, it is desirable to employ the calibration coefficient using the Mo target supplied by AIST. Furthermore, the indication of quality of radiation should be made severe, too. To perform equal dosimetry with a diagnosis domain, it is necessary to supply the calibration coefficient of the other target/filters.