本研究以假體模擬人體對X光的散射，評估在X光照射時，人體存在對空間劑量分布的影響。結果顯示當有假體時，空間之劑量分布改變甚大，高度在0.8m之層面，TLD所接受的劑量較無假體時減少約18%；而高度在1.3m與1.8m之層面，TLD所接受的曝露較無假體時的曝露分別多了18%與36%。推論當實際有平躺之受照者時，由上往下照之X光曝露分布改變應類似，即人體上方空間的劑量將增加；而人體下方空間的劑量將減少。

A radiographic positioning phantom was adopted to study the changing of dose distribution by the X-ray scattering from the body of the phantom. The result showed that the space dose distribution had a large changing when the phantom was positioned on the table or not. Compared to nothing on the clinical table, the total dose with a phantom that was measured by TLDs decreased 18% at an altitude of 0.8 meter. On the other hand, the doses with a phantom increased 18% and 36% at the altitudes of 1.3 meters and 1.8 meters, respectly. The study expected the changing of dose distribution is similar when the phantom was replaced by an actually person as the x ray beam of exposure is from up to down, The doses will increase on the space between the X-ray tube and exposured body and decrease under the space of the exposured body.