EFFECT OF KVP AND SLICE THICKNESS ON SLICE THICKNESS MEASUREMENT FROM PHANTOM AAPM

• Main Author: Ayu Damira, Sarah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68427
• Institution: Institut Teknologi Bandung

Research has been conducted on the effect of kVp and slice thickness on the measurement of slice thickness from phantom AAPM. This study aims to determine slice thickness by manual and automatic methods and compare the measurement results of the two methods. The parameters used in this study are exposition variations of the kVp value and slice thickness variations. CT scan image data was collected at the Radiology Installation of the Cideres Regional General Hospital, Majalengka Regency, West Java. The CT scan tool used is Toshiba Alexion 16 multi-slice brand, and the phantom used is AAPM CT performance phantom slice thickness testing section. The imagery data is then processed using IndoQCT software for automatic measurement and Image J for manual measurement. Manual measurements are obtained by plotting the image profile and the Full-Width Half Maximum (FWHM) value from the profile curve. This FWHM value is the value of the slice thickness measured. As for the automatic measurement of slice thickness, you can immediately find the slice thickness value from IndoQCT software. This study found that the slice thickness value for the manual method obtained a difference range of 0.00 – 0.35 mm and automatically obtained a difference range of 0.03 – 0.34 mm. Based on the scope of difference, the value is still below 0.5 mm. Therefore, this slice thickness value is still within the tolerance limit set by BAPETEN, and the CT scan tool produces good image quality. The study also analyzed image quality for contrast, blurring, and noise on kVp and slice thickness variations. It was obtained that the large values of kVp and slice thickness caused the image contrast to decreasing with a contrast range of 191.11- 355.03 HU. Then, a blurring value increases when the kVp value gets more significant with a range of 1.54 – 2.55 mm, and the slice thickness value gets smaller with a range of 1.46 – 2.82 mm. Furthermore, an enlarged noise value was also obtained when the kVp and slice thickness values were reduced in the 5.21 – 12.42 HU range.