Optimization Of Radiation Dose And Image Quality In Computed Tomography Imaging

Abstract

Improvements in the benefit of CT have been so dramatic that a tendency

exists to the overuse. CT is a diagnostic imaging modality giving higher patient

dose in comparison with other radiological procedures. While the benefits of CT

exceed the harmful effects of radiation exposure in patients, increasing radiation

doses to the population have raised.

The main objective of this work was to find an optimization approach to

minimize the radiation dose to adult patients undergoing CT examinations, while

maintaining the diagnostic image quality.

This study was done on four different CT scanners (2, 4, 16 and 64), in

Khartoum state, during the period 2013-2016. One way to achieve optimization is

to reduce tube rotation time, which has been shown to be effective in reducing

absorbed dose to patients undergoing CT examinations.

A total of 404 CT patients’ examinations 240 before and164 after

optimization were included in the study. The results from this study indicate that

radiation dose DLP was reduced significantly by (14.3%-59.7%) mGy.cm in Brain

Protocol and by (1.1%-28.2%) mGy.cm in Chest Protocol and by (16.2%-55.4%)

mGy.cm in Abdomen protocol for the four scanners. Image noise generally

increases, subjective image quality was affected by an increased noise level in the

images but was judged to be acceptable in all groups.Using this protocol, effective

dose was reduced by (22.9%-47.0%) mSv in Brain and (2.6%- 25.3%) mSv in

Chest and (15.6%-49.2%) mSv in Abdomen which in turns reduced the cancer

probability. This study showed that optimizing the dose and image quality for the

four CT scanners is dependent on choosing the appropriate parameter for the exam

protocol. Finally, concerted efforts and research should be directed to define

diagnostic image quality, and research efforts must focus on patient- and

technology- based methods to achieve a diagnostic- quality CT image at an

optimum radiation dose. A team approach is essential in CT protocol review. And

there is still considerable room for optimization and continuous developments of

new technologies aim to optimize image quality and radiation absorbed dose to the patient.