Profile of CT scan output dose in axial and helical modes using convolution

13th South-East Asian Congress of Medical Physics 2015

物理学;医药卫生

Anam, C.^1,2 ; Haryanto, F.^2 ; Widita, R.^2 ; Arif, I.^2 ; Dougherty, G.^3

Department of Physics, Faculty of Mathematics and Sciences, Diponegoro University, Indonesia^1

Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Indonesia^2

California State University (CSU) Channel Islands, CA, United States^3

关键词: Dose profile;    Helical modes;    Patient dose;    Rectangular function;    Single scan;    Solid state detectors;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/694/1/012034/pdf
DOI  :  10.1088/1742-6596/694/1/012034

学科分类：卫生学

来源: IOP

【 摘 要 】

The profile of the CT scan output dose is crucial for establishing the patient dose profile. The purpose of this study is to investigate the profile of the CT scan output dose in both axial and helical modes using convolution. A single scan output dose profile (SSDP) in the center of a head phantom was measured using a solid-state detector. The multiple scan output dose profile (MSDP) in the axial mode was calculated using convolution between SSDP and delta function, whereas for the helical mode MSDP was calculated using convolution between SSDP and the rectangular function. MSDPs were calculated for a number of scans (5, 10, 15, 20 and 25). The multiple scan average dose (MSAD) for differing numbers of scans was compared to the value of CT dose index (CTDI). Finally, the edge values of MSDP for every scan number were compared to the corresponding MSAD values. MSDPs were successfully generated by using convolution between a SSDP and the appropriate function. We found that CTDI only accurately estimates MSAD when the number of scans was more than 10. We also found that the edge values of the profiles were 42% to 93% lower than that the corresponding MSADs.