Study on the effects of patient miscentring on radiation dose and image quality in CT imaging

Incorrect setting of patient positioning on the treatment table always happened in diagnostic imaging which leads to misinterpretation of data and degrades the image quality. This study focuses to evaluate the effects of patient miscentring on patient dose and image quality in CT imaging. The CT...

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Main Author:	Teo, Siti Humairah Mohd Razlan
Format:	Thesis
Language:	English
Published:	2020
Subjects:	R Medicine
Online Access:	http://eprints.usm.my/54238/1/Siti%20Humairah-24%20pages.pdf
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spelling	my-usm-ep.542382022-08-23T03:44:23Z Study on the effects of patient miscentring on radiation dose and image quality in CT imaging 2020-08 Teo, Siti Humairah Mohd Razlan R Medicine Incorrect setting of patient positioning on the treatment table always happened in diagnostic imaging which leads to misinterpretation of data and degrades the image quality. This study focuses to evaluate the effects of patient miscentring on patient dose and image quality in CT imaging. The CT scan parameter, patient positioning information was taken from the head and thorax-abdomen-pelvic protocols acquired in 128-slice Siemens SOMATOM Definition AS + CT system. This study started with the retrospective survey on patient miscentring shifting data by using data registration (DoseWatch, version 1.2, GE Healthcare) to collect information about patient isocenter shifting. The range of miscentring for minimum and maximum had been obtained and will be used as guidelines in phantom studies. CTDI phantom and water phantom were used in dose measurement and image quality assessment respectively. CTDIw is used to calculate the dose across FOV of the phantom. In this study, isocentre shifting of both axes (positive or negative axis) can cause an increase or a decrease of CTDIw across the FOV. This research showed that the shift x- and y- axes and the phantom dose (CTDIw) have weak correlation which is 0.1796 and -0.2127 respectively for the 16cm CTDI phantom. While for 32 cm, the correlation is -0.3555 (weak) and 0.5582 (strong) between both variables. In image quality assessment, SNR is observed. Miscentring of both axes also associated with the quality of the image produced. There is no correlation between x-axis shifting and SNR (r = -0.0267). However, the correlation between mean HU and mean SD with the shift x-axis is weak. There is a strong positive association between the y-axis shifting and the SNR (r = 0.8156). The correlation between mean HU and mean SD also good with the y-axis. 2020-08 Thesis http://eprints.usm.my/54238/ http://eprints.usm.my/54238/1/Siti%20Humairah-24%20pages.pdf application/pdf en public masters Universiti Sains Malaysia Pusat Pengajian Sains Kesihatan
institution	Universiti Sains Malaysia
collection	USM Institutional Repository
language	English
topic	R Medicine
spellingShingle	R Medicine Teo, Siti Humairah Mohd Razlan Study on the effects of patient miscentring on radiation dose and image quality in CT imaging
description	Incorrect setting of patient positioning on the treatment table always happened in diagnostic imaging which leads to misinterpretation of data and degrades the image quality. This study focuses to evaluate the effects of patient miscentring on patient dose and image quality in CT imaging. The CT scan parameter, patient positioning information was taken from the head and thorax-abdomen-pelvic protocols acquired in 128-slice Siemens SOMATOM Definition AS + CT system. This study started with the retrospective survey on patient miscentring shifting data by using data registration (DoseWatch, version 1.2, GE Healthcare) to collect information about patient isocenter shifting. The range of miscentring for minimum and maximum had been obtained and will be used as guidelines in phantom studies. CTDI phantom and water phantom were used in dose measurement and image quality assessment respectively. CTDIw is used to calculate the dose across FOV of the phantom. In this study, isocentre shifting of both axes (positive or negative axis) can cause an increase or a decrease of CTDIw across the FOV. This research showed that the shift x- and y- axes and the phantom dose (CTDIw) have weak correlation which is 0.1796 and -0.2127 respectively for the 16cm CTDI phantom. While for 32 cm, the correlation is -0.3555 (weak) and 0.5582 (strong) between both variables. In image quality assessment, SNR is observed. Miscentring of both axes also associated with the quality of the image produced. There is no correlation between x-axis shifting and SNR (r = -0.0267). However, the correlation between mean HU and mean SD with the shift x-axis is weak. There is a strong positive association between the y-axis shifting and the SNR (r = 0.8156). The correlation between mean HU and mean SD also good with the y-axis.
format	Thesis
qualification_level	Master's degree
author	Teo, Siti Humairah Mohd Razlan
author_facet	Teo, Siti Humairah Mohd Razlan
author_sort	Teo, Siti Humairah Mohd Razlan
title	Study on the effects of patient miscentring on radiation dose and image quality in CT imaging
title_short	Study on the effects of patient miscentring on radiation dose and image quality in CT imaging
title_full	Study on the effects of patient miscentring on radiation dose and image quality in CT imaging
title_fullStr	Study on the effects of patient miscentring on radiation dose and image quality in CT imaging
title_full_unstemmed	Study on the effects of patient miscentring on radiation dose and image quality in CT imaging
title_sort	study on the effects of patient miscentring on radiation dose and image quality in ct imaging
granting_institution	Universiti Sains Malaysia
granting_department	Pusat Pengajian Sains Kesihatan
publishDate	2020
url	http://eprints.usm.my/54238/1/Siti%20Humairah-24%20pages.pdf
_version_	1747822279897645056

Study on the effects of patient miscentring on radiation dose and image quality in CT imaging

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