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Journal : Jurnal Fisika Unand

Uji Kualitas Citra Pesawat CT-Scan Menggunakan Phantom ACR (American College of Radiology) di Instalasi Radiologi Rumah Sakit Universitas Andalas Machmudah; Muttaqin, Afdhal; Oktavia, Amel
Jurnal Fisika Unand Vol 14 No 1 (2025)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.14.1.45-51.2025

Abstract

This research aims to obtain optimal image quality by ensuring that the CT Number measurement results do not exceed the limits set using Phantom ACR in the Radiology Installation of Andalas University Hospital with a Philips brand CT-Scan 64 Slice machine, because CT-Scan image quality testing is an important step to ensure optimal performance of radiology diagnostic tools and guarantee the accuracy of examination results. This research uses an experimental method with an evaluation consisting of four modules: Module 1 (CT Number accuracy) shows that the values for Polyethylene, Air, Acrylic and Water materials are within the tolerance limits of BAPETEN No. 2 of 2022 is ±5 HU, while the bone material does not meet the criteria, which indicates the need for additional calibration for high density materials. Module 2 (low contrast resolution), CNR (Contrast to Noise Ratio) value of 2.91 shows clear contrast between structures with low noise, meets BAPETEN standard No. 2 of 2022. Module 3 (CT Number uniformity), uniformity testing produces standard deviation values below the limit ≤ 2 HU, indicating good uniformity in the center and edges of the image, making it reliable for clinical applications. Module 4 (spatial resolution with high contrast), the CT-Scan system shows a resolution of 6 lp/cm, in accordance with the minimum limit set by BAPETEN No. 2 of 2022. Overall, this research shows that the CT-Scan system can produce images that meet BAPETEN standards No. 2 of 2022 for good image quality and can be applied in clinical practice, but for bone material it does not meet the criteria with an average value of 838.1 ± 17.4 HU.
Implementasi Nilai Exposure Index dan Indeks Massa Tubuh dalam Pemilihan Parameter Sistem Automatic Exposure Control Pada Radiografi Toraks (Studi Kasus Pada Rumah Sakit Universitas Andalas) Yulma Susanto, Riyan; Adrial, Rico; Milvita, Dian; Oktavia, Amel
Jurnal Fisika Unand Vol 14 No 4 (2025)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.14.4.339-345.2025

Abstract

This study aims to analyze the application of EI (Exposure Index) values to evaluate exposure indications in thorax PA examinations. It also examines the influence of patient BMI (Body Mass Index) on parameter selection, such as estimated body size in the AEC (Automatic Exposure Control) system. Data collection was conducted on patients aged 15-73 years undergoing thorax PA examinations using the AEC system. The data collected included patient mass (kg), height (m), selected estimated body size on the AEC system, exposure factor values (source voltage (kV)), and EI values. The method used to evaluate the implementation of EI values involved comparing the EI values from the examinations with the vendor-recommended EI values for CR (Computed Radiography) to determine the resulting exposure indications. Furthermore, the influence of BMI on parameter selection in the AEC system was analyzed using a simple linear correlation test to determine the correlation between BMI values and the resulting EI values. The study results showed that thorax PA examinations using the AEC system produced optimal exposure indications in 57% of cases and underexposure indications in 43% of cases. Causes of underexposure indications included the selection of exposure factors that were not fully adjusted to the patient's physical condition based on BMI values, delay time processing on the imaging plate, and the use of collimation fields exceeding diagnostic needs in some examinations. BMI values showed a significant correlation with EI values.