Investigation of testing method on spiral CT uniformity

Objective: To assess the factors influencing testing standards of CT uniformity and put forward mending method. Methods: The CT uniformity of two different types was obtained and the factors influencing testing standards of CT uniformity were observed with changing of conditions of phantom and CT scans. Results: The uniformity in conventional CT was better than that in spiral CT with software emended function before packed with aluminum loop with the condition of head CT scan, and just the opposite result was obtained after packing. But there was no obviously difference in the uniformity between conventional and spiral CT with the condition of body scan. Conclusions: The skull effect should be considered with the condition of head CT scan in the CT uniformity testing. Aluminum loop with 2 mm thickness around the phantom should be used on CT testing with pre-emended function. CT scan in uniformity testing with body condition should be used without aluminum loop. Other-wise, testing standards should be broadened