Regional survey of CT dose indices in India.

This study intends to evaluate the current level of computed tomography (CT) scanner doses installed in a region in India. In-site CT dose measurement was performed for 127 CT scanners in a region in India. CT dose index (CTDI) was measured using a 10 cm3 pencil ion chamber and 32-cm polymethyl methacrylate body phantom. The CT numbers and image noise were measured for the phantom using software available on each CT scanner. Of the 127 CT scanners, 13 were conventional, 53 helical single-section, 44 multidetector row CT (MDCT) and 17 refurbished machines. The mean-weighted CTDI (CTDI(w)) values calculated using standard exposure parameters for conventional, conventional refurbished, single-section helical scanner (SSHS), refurbished SSHS and MDCT scanners were 7.5, 6.53, 6.8, 6.6 and 7.04 mGy. Twenty-seven CT scanners had deranged CT numbers. Periodic quality assurance and regional dose surveys would be beneficial to set up regional reference levels in India.