An innovative instrumentation system for measuring the computed tomography dose index

This paper presents results from a semiconductor-based detector system to be used as an alternative for measuring the computed tomography dose index (CTDI) which is the dose descriptor in CT dosimetry. The 100 mm long ionization chamber is the device normally used, however some works have already indicated that small devices could replace the long ion chamber to improve the quality assurance procedures in CT dosimetry. This work shows how one can calculate the CTDI with a SMD phototransistor and its angular response for tomography beams.