CTSCAN اندازه گيري و مقايسه دز تيروييد ناشي از پرتوهاي پراكنده در تصويربرداري از قفسه سينه به چهار روش

Measurement and comparison of thyroid dose duo to scattered radiation in different methods of thorax CT Scan

In this invivo study, 120 adult patients were selected by BMI factor (30 patients in each method) for measuring thyroid dose. CT Scan methods included conventional CT and spiral CT with three different pitch factors (1.2, 1.5, L7). By use of TL dosimetry, thyroid dose due to scattered radiation in thorax CT an was measured and the mean of values in each method compared by t-test with re a =0.05). Dose values also normalized by BMI length of scan (L), patient weight (W). BMI and lenght of scan together and compared by t-test with reliability of 95% (alpha=0.05). Results indicates spiral CT with pitch factor greater than one, reduces thyroid dose in comparison of conventional CT and also increase of pitch ctor decreases thyroid dose.