The diagnostic X-ray exposure technique guidelines for elephants’ limbs in Elephant Hospital, Thai Elephant Conservation Center, Thailand

Abstract

Background: Radiographic image is the first of choice for diagnosing complications involving elephants’ limbs. The extreme thickness of their limbs causes inaccurate image quality. Therefore, an appropriate procedure is hereby investigated as a matter concerned. Because of difference of X-ray absorption in elephant tissue from human tissue, the Sante’s rule cannot be directly applied. Objectives: This study sought to acquire the appropriate equation by modifying the Sante’s rule with a tissue factor for calculating the exposure technique for Asian elephants’ limbs. Materials and methods: Firstly, capacity of a mobile X-ray machine was evaluated in terms of dose rate, precision, and accuracy of radiation. The exposure techniques were then designed using the modified Sante’s rule and tested with the hind limbs of 10 live elephants. Results: Output of X-ray machine revealed the dose rate in milli-Rontgen per milli-Ampere-sec equal to 4×10-4 of kVp2, and the machine factor equal to 6.4. The radiographic images taken using the calculated exposure techniques showed good quality, and so, it is possible to differentiate between the medullar and the cortex of the bone. Conclusion: Equations suitable for designing the exposure technique are kVp equal to two times of sample thickness in centimeter plus source image distance in inche and the tissue correcting factor 5, and mAs equal to two-fifths of the sample thickness in centimeters.

Keywords

• Asian elephant
• limb
• diagnostic X-ray
• Sante’s rule