Phantom design for analysis of CT image quality from Single-source and Dual-source CT scan

Abstract

Computed Tomography (CT) Scanner is a three-dimensional body imaging modality. For observation of moving organs, in addition to using Single-source CT (SSCT), Dual-source CT (DSCT) has been developed which is equipped with primary and secondary x-ray sources. The position of the two DSCT sources forms an angle of 90°, and at the time of image acquisition both rotate 90°. Thus the process of image acquisition of a moving body can be carried out in a relatively short time. If the same examination using SSCT, it is necessary to decrease the movement of organs which generally use beta blockers. In this research, in-house phantom has been designed to analyze the image quality character of the two types of CT which will then be compared. Phantom is cylindrical in shape and has a diameter of 20 cm and a length of 12 cm, divided into three sections of 4 cm each. The first module, phantom is intended for noise measurement, in the phantom implanted 16 cylindrical objects with diameters of 10 mm and 15 mm, made of 4 types of material with different Hounsfield Unit (HU) values, namely teflon (941.31 ± 14.61) HU, water (0.548 ± 0.43) HU, polystyrene (-26.38 ± 13.55) HU, and air (984.32 ± 27.97) HU. The second module, phantom will be used to assess the detectability. This section is filled with 26 cylindrical pipes with diameters, 2, 3, 4, 5, 6 mm for each of the 5 pipes and one other pipe with a diameter of 10 mm. All of these pipes will be filled with contrast media Iodine with varying concentrations. The third module, phantom will be used to measure spatial resolution and homogeneity. In this section copper ball objects will be implanted with a diameter of 0.19 mm and a length of 4 cm. Furthermore phantom will be used for measurement of noise, spatial resolution and detectability of this CT image from dual-source and single-source CT scans with the exposure conditions adjusted for clinical use.