Optimization of Dose and Image Quality of CT-Scan for Pitch Variations as Radiation Protection Efforts at Adam Malik Central General Hospital Medan

Abstract

Optimization is an effort to ensure patient radiation safety and is the main action in overcoming concerns about CT-Scan radiation exposure. This led to the emergence of various measures to reduce the dose. This study aims to obtain a minimal dose with a high-quality image. Optimization efforts were carried out by the radiology team at Adam Malik Hospital Medan using a 16 slice GE CT-Scan and a water phantom with a diameter of 16 and 32 cm and an image quality questionnaire form. Collected data by observing the head, chest, and abdomen CT-Scan in adult patients (≥15 years). The data taken is the value of CTDI vol and DLP for a year. Then a water phantom scan was carried out with the head protocol using pitch parameters 0.562 and 0.938. The chest and abdomen use pitches of 1.375 and 1.75. The results obtained were evaluated and applied to patients, then filled in the image quality questionnaire scores. The results of CTDI_vol and DLP values with 16 and 32 cm water phantom scans showed a decrease in the dose value; for pitch 0.938, it was 1.6% lower than pitch 0.562, and pitch 1.75 was 1.2% lower, compared to pitch 1.375. For CT head examination using a pitch of 0.963, the CTDI_vol value was 1.5%, and DLP was 2%. For chest using a pitch of 1.75, CTDI_vol values were 1.3% and DLP 2%, while abdominal examination with a pitch of 1.75 obtained CTDI_vol values 1.8% and DLP 1.4%. From these three results, the CTDI_vol and DLP values were higher than the national DRL values. The value obtained is higher than the national DRL due to differences in the phantom test protocol with clinical implementation and the lack of accuracy in using other parameters. Changes in scan parameters are not comprehensive. Obtained a score of 3 in the questionnaire form stating that the radiology doctor can still interpret the image. This study concluded that it could make optimization efforts by changing the pitch parameter by paying attention to other parameters without reducing the quality of the image interpreted by the radiologist.