ANALISIS AUDIT DOSIS SEBAGAI UPAYA OPTIMISASI PADA PEMERIKSAAN CT ABDOMEN INTRAVENOUS (IV) DI RUMAH SAKIT UMUM PUSAT ADAM MALIK MEDAN

Abstract

Audits are conducted on CT scan examinations using dose metrics to assess the need for optimization in computed tomography procedures. Diagnostic reference levels (DRL) provide an indicator that helps optimize patient medical exposure by adhering to the recommendations of the International Commission on Radiological Protection (ICRP). In the radiology unit at Adam Malik Hospital, efforts were made to reduce the radiation dose given to patients during CT abdominal IV examinations by using the lowest possible radiation dose without compromising image quality. The CT scans were carried out on 1526 patients using a Philips Ingenuity brand CT Scan, type MRC880, serial number 168014, and a built-in phantom as a patient representation. The radiation output was represented by the volumetric computed tomography dose index (CTDIvol) and dose length product (DLP). The physical parameters of tube voltage (kV) and pitch were evaluated to optimize the CT abdominal IV dose. At the same time, the Signal Difference to Noise Ratio (SDNR) was used to analyze image quality for each change in physical parameters. The results of dose audit data for CT abdominal IV patients, when using parameters of 120 kV and 1.1-1.2 pitch, obtained a Q2 value of 1452 mGy.cm higher than I-DRL of 1360 mGy.cm. Data from measurements with a phantom at 100 kV and 1.40-1.48 pitch showed a lower dose than the previous parameters. CT abdominal IV patient dose data with 100 kV and 1.40 -1.48 pitch showed that the DLP value in Q2 was 755 mGy.cm, lower than the previous measurement of 1452 mGy.cm. This means that there was a 52% decrease in dose after changing the parameters of 100 kV and 1.40 -1.48 pitch with image quality remaining optimal. The highest SDNR value of 12 was obtained at 100 kV and 1.48 pitch. The results indicate that it is necessary to establish a new protocol for CT abdominal IV with parameters of 100 kV and 1.40 -1.48 pitch for adult patients over 15 years of age. Keywords: optimization, radiation dose, image quality, CT abdomen