PENGARUH MEDIA KONTRAS TERHADAP NILAI HU, CTDI DAN DLP PADA PEMERIKSAAN CT SCAN UNTUK PENENTUAN NILAI DOSIS TIPIKAL = THE EFFECT OF CONTRAST MEDIA ON HU, CTDI AND DLP VALUES AT CT-SCAN EXAMINATION TO DETERMINE TYPICAL DOSE VALUES

Background. The increasing use of CT-Scan in medical diagnostics raises concerns about the radiation dose received by patients, especially when used with contrast media. This study aims to determine the effect of contrast media on Hounsfield Unit (HU), Computed Tomography Dose Index (CTDI), and Dose Length Product (DLP) values to support the determination of Typical Dose Values (NDT). Methods. This study uses an experimental quantitative approach by comparing CT-Scan examination data before and after contrast media administration in a number of patients. HU values are measured in the main blood vessels, while CTDI and DLP are obtained directly from the CT Scanner console. The study subjects consisted of 30 abdominal patients and 26 head patients for NDT analysis, and 20 patients for HU change analysis. Result. The results showed that there was a significant increase in HU values after contrast medium administration. For abdominal patients, the highest HU value from the three measurement points increased from 43.53 to 290.58. In the Head examination, the highest HU value increased from 35.98 to 67.65 after contrast medium was administered. Data analysis showed an increase in NDT after contrast use. The CTDIvol and DLP values were 5.05 mGy and 118.13 mGy.cm (abdominal CT), and 49.35 mGy and 1108.30 mGy.cm (head CT), respectively. Validation with DRL limit values was still below the standard. This study emphasizes the importance of optimizing the use of contrast media to obtain quality diagnostic images without ignoring radiation safety aspects. The conclusion of this study is that contrast media not only improves image quality by increasing HU values, but also affects the radiation dose received, so careful scanning parameter settings are needed to maintain a balance between image quality and radiation dose.

Keyword: contrast media, hounsfield unit, typical dose value, diagnostic reference level, abdomen, head.