X-ray detection using a ceramic-substrate silicon X-ray diode and its application to computed tomography using gadolinium media

抄録

Silicon X-ray diode (Si-XD) is a high-sensitivity Si photodiode (PD) selected for detecting X-rays, and the X-ray sensitivity of the Si-XD was 2 times as high as that of Si-PD with a cerium-doped yttrium aluminum perovskite [YAP (Ce) ] crystal scintillator. X-ray photons are directly detected using the Si-XD without a scintillator, and the photocurrent from the diode is amplified using current-voltage (I-V) and voltage-voltage (V-V) amplifiers. The output voltage from the V-V amplifier is sent to an analog-digital converter. Computed tomography (CT) system was constructed using the Si-XD to evaluate imaging characteristics. CT is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. The exposure time for obtaining a tomogram was 5 min at a scan step of 0.5 mm and a rotation step of 3.0°. The maximum output voltage from the V-V amplifier is regulated to 3.0 V to perform CT, and the CT was carried out using gadolinium-based contrast media.