Simulated increases body fat with phantom in bone mineral density measurements by fan /pencil beam DXA

• Main Authors: Kai-Yi Hung, 洪凱羿
• Other Authors: 邵佳和
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/84016158628359387194

碩士 === 中山醫學大學 === 生物醫學科學學系碩士班 === 104 === Purpose In the past other studies we found changes in body thickness will have an impact to bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA). But those studies subjects are all older adult, the effect of body thickness in child still not clear. Materials and Methods This study we simulated body fat by bolus to observe the effect of fat layering on BMD measurements in 5 y/o , 10 y/o and adult phantom by fan and pencil beam DXA. Also we measured effective dose by Thermolummescent detectors (TLD) to observe the different of fan and pencil beam DXA. Results In pencil beam DXA, associations between body fat thickness and BMD is 0.8554(5y/o) , 0.2543(10y/o) and 0.9596(adult). In fan beam DXA, associations between body fat thickness and BMD is 0.1535 (5y/o) , 0.6341 (10y/o) and 0.9641 (adult). The fan beam DXA BMD measurement effective dose were higher than pencil beam(effective dose: 26.23vs14.79μSv(5y/o) , 14.89 vs 6.93 μSv(10y/o) and 45.97 vs 6.12(adult)). Conclusion Pencil and fan beam DXA BMD measurement both affected by body thickness change. Pencil beam DXA had smaller effect by body thickness change in both phantom. Effective dose from pencil and fan beam DXA can not separate from natural background radiation, but fan beam had higher effective dose than pencil beam.