OPTIMIZATION OF IMAGE QUALITY IN A RADIOTHERAPY CT SIMULATOR: DEVELOPMENT OF A SPECIFIC PROTOCOL

This study aimed to optimize the scan parameters of the Siemens Somatom Scope CT simulator to ensure optimal image quality for the detection of brain tumors. To achieve this, measurements were performed using the Catphan CTP 503 phantom, evaluating metrics such as the contrast-to-noise ratio (CNR), low-contrast visibility (LCV), signal-to-noise ratio (SNR), noise level, and uniformity index (UI). The optimization process involved adjusting scan parameters such as kilovoltage (kV), tube current (mA), and the automatic exposure control system (CareDose4D). The results showed that the optimized protocol (Protocol 2) achieved the highest CNR values—61.41 for polymethylpentene (PMP) and 47.9 for low-density polyethylene (LDPE)—as well as the best LCV and an SNR of 31.2. In addition, it exhibited the lowest noise level (0.3%) and the best uniformity index (0.03). These findings suggest that Protocol 2 may be an effective tool for improving the accuracy of brain structure delineation and other anatomical regions, thereby enhancing radiotherapy treatment planning.