Necessity of Direct Dose Measurement during Current X-ray Diagnosis

During current medical X-ray diagnosis, an automatic exposure control system is widely used. The system can provide proper X-ray exposure, which varies by the patients physical type. It is difficult to measure exposure dose using a traditional dosimeter. Therefore, we proposed using a small-type OSL dosimeter for direct dose measurements. For this application, evaluation of basic properties such as angular and energy dependences is important. Moreover, even when they are derived, some ideas to apply them to using the dosimetry is needed. In this paper, we will introduce our concept; we made a calibration curve using 83 kV X-rays and proposed that an uncertainty of 15% should be added. Moreover, when the dosimeter is applied to CT examination, consideration of pitch factor is needed. We estimated that the uncertainty of PF is at most 25%, and overall uncertainty will be approximately 30%. It is also important to determine whether or not the dosimeter influences the medical image. We presented typical X-ray images of chest X-ray and CT scan of whole body, and explain that the OSL dosimeter can be applied to actual clinical examinations.