A Study on the Reduction of Scattered Ray in Outside Radiation Field

In this research, The way to decrease a patient's exposure dose by reducing the scattered radiation dosage outside a radiation field with an diagnosis X-ray was examined. The scattered radiation dosage reaching other parts outside the radiation field was to be reduced by attaching a self-produced $150{\times}190mm^2$ lead plate to the lower part of a collimator. When a lead plate was inserted additionally and the scattered radiation dosage of the X axis was measured in the direction of the central X-ray axis, It was found out to have been decreased by 26 to 36%, and in the direction of Y axis, which was vertical direction from the central axis, The scattered radiation dosage depending on whether a lead plate was used or not displayed no large differences. These results shows that the impact of the scattered radiation by the off focus X-ray that was generated around the focus was bigger than that generated by the shutter of the collimator. Therefore it has been concluded that installing an additional lead plate in the lower part of the existing collimator can decrease the scattered radiation dosage outside a radiation field.

조사야 외부의 산란선량 감소 방법에 관한 연구

본 연구는 진단용 X선 발생장치에서 조사야 외부의 산란선량을 감소시켜 환자의 피폭 선량을 감소시키기 위한 방법이다. 자체 제작한 $150{\times}190mm^2$ 납판을 콜리메이터 하단에 부착함으로써 조사야 이외의 부위에 도달하는 산란선량을 감소시키고자 하였다. 납판을 추가로 삽입 후 X선 관축방향인 X-축의 산란선량을 측정한 결과 26 ~ 36% 감소하는 것으로 나타났으며, 관축의 수직 방향인 Y-축 방향에서는 납판의 사용 유무에 따른 산란선량은 큰 변화를 나타내지 않았다. 이러한 결과는 콜리메이터 Shutter에 의해서 발생하는 산란선 보다는 초점 근방에서 발생하는 초점외 X선에 의한 산란선 영향이 크다는 것을 의미한다. 따라서 기존의 콜리메이터 하단에 추가로 납판을 설치하는 것이 조사야 외부의 X-축 산란선량을 감소시키는 방법으로 판단되어진다.