Characterization of a cable-free system based on p-type MOSFET detectors for "in vivo" entrance skin dose measurements in interventional radiology.

摘要: Purpose: During radiological interventional procedures (RIP) the skin of a patient under examination may undergo prolonged x-ray exposure, receiving dose as high 5 Gy in single session. This paper describes use OneDoseTM cable-free system based on p-type MOSFETdetectors to determine entrance skindose (ESD) at selected points during RIP. Methods: At first, some dosimetric characteristics detector, such reproducibility, linearity, and fading, have been investigated using C-arc source radiation. The reference setting (RS) was: 80 kV energy, 40 cm × field view (FOV), current-time product 50 mAs distance (SSD) cm. A calibrated PMX III solid state detector was used Gafchromic® films an independent test entire procedure. calibration factor for RS correction factors functions tube voltage FOV size determined. Results: Reproducibility ranged from 4% low doses (around 10 cGy measured by detector) about 1% 2 Gy). response found be linear with respect both dosemeasured voltage. fading has shown that maximum deviation optimal reading conditions (3 min after irradiation) 9.1% corresponding four irradiations one hour read 3 last exposure. energy range is times larger than MV range. fifth order fourth polynomial were provide size, respectively, measurement settings different RS. ESDs applying proper agreed within standard (SD) detector. agreement SD compared system, well. global uncertainty associated established our experiments, 7% 10%, depending duration RIP due fading. These values are much lower commonly accepted general diagnostic practices (20%) same recommended risk deterministic side effects (7%). Conclusions: sensitivity capable measuring