Effect of different source-to-image distance on radiation dose and the quality of image in posteroanterior hand X-ray examination

• Main Authors: Sayed, Inayatullah Shah, Nik Lah, Nik Noor Izzati
• Format: Conference or Workshop Item
• Language: English; English; English; English; English; English
• Published: 2021
• Subjects: QC Physics
• Online Access: http://irep.iium.edu.my/95289/3/95289_ISRP-%2015_Abstract.pdf; http://irep.iium.edu.my/95289/9/ISRP-15%20Abstract%20Book%20-%20FP.png; http://irep.iium.edu.my/95289/10/Abstract%20ISRP%20-15.png; http://irep.iium.edu.my/95289/11/ISRP15_A207_Sayed_23112021.pdf; http://irep.iium.edu.my/95289/25/ISRP-15v4e.pdf; http://irep.iium.edu.my/95289/26/95289_Effect%20of%20different%20source-to-image%20distance.pdf; http://irep.iium.edu.my/95289/

In clinical settings, the source-to-distance (SID) is adjusted using measuring tape attached to the x-ray tube. However, this method is ignored when hand extremities X-ray examinations are involved. Variation in SID can affect radiation dose to hand and quality of image. In this study upper extremities of the hand area were included. It is because the number of hand injuries cases at the hospitals is higher compared to other upper extremities such as the forearm, elbow and humerus. The purpose of this work was to investigate the effect of different SID on entrance surface dose (ESD) and quality of image for posteroanterior (PA) projection. The Siemens Multix Top system was used selecting 55 kVp and 1.6 mAs. The SID selected was 95, 100, 105, 110 and 115 cm. The anthropomorphic hand-wrist phantom was placed over the cassette with the third metacarpophalangeal joint as the centre of the anatomical structure. Twelve nanoDot OSLDs at various locations on the phantom were positioned. The ESD readings were repeated for three times at each SID in order to record an average value. Five images of PA hand X-ray examinations were produced in order to measure signal-noise-ratio (SNR) using ImageJ for image quality evaluation. The mean ESD value at the centre of anatomical structure, which is the metacarpophalangeal (MCP) joint of the third digit decreased as SID increased. There is a significant difference between the mean ESD at MCP joint of the third digit and SID (p<0.05). However, inconsistent ESD values at other locations were observed. In terms of image quality, the results also show inconsistent pattern of SNR for each image. To conclude, the increase in SID, lowers the ESD and image quality. It is suggested that the SID need to be adjusted manually when upper extremities of the hand X-ray examinations are performed.