Fractionated Stereotactic Radiotherapy (FSRT) Using Gold Markers : A Comparison of the Isocenter between Multiple Arcs and Static Conformal Beams

금속표지자를 이용한 다중호형 정위방사선치료와 입체조형 정위방사선치료의 회전중심점 비교

The aim of the study was to assess the isocenter deviation between multiple arcs and conformal beams in frameless FSRT. Forty seven patients received single isocenter radiosurgery or therapy (SRS/T) using available framelss FSRT system from Aug. 1997 to Dec. 2m. In choosing multiple arc FSRT or conformal FSRT, we had considered one of two techniques with respect to tumor size and tumor shape. In multiple arc FSRT, the average and standard deviation (SD) of the isocenter deviation was 0.2 mm (SD 0.2 mm), 0.2 mm (SD 0.2) and 0.3 mm (SD 0.2 mm)in the lateral (x), anterior-posterior (y) and cranio-caudal directions (z). In conformal FSRT, the average deviation and SD of the isocenter deviation was 0.2 mm (SD 0.2 mm), 0.3 mm(0.2 mm) and 0.4 mm (SD 0.2 mm) in the x, y and z directions. The average spacial deviation ($\Delta$r) was 0.41 mm and 0.54 mm in multiple arcs and conformal beams, respectively. The isocenter deviation using frameless FSRT system was similar value between multiple arcs and conformal beams. In practice, we believed we can select the appropriate treatment technique according to tumor shape and size.

본 연구는 무고정틀정위방사선치료의 다중호형 기법과 입체조형기법간의 회전중심점의 오차를 알아보고자 하였다. 1997년부터 2000년 12월까지 무고정틀정위방사선치료를 받은 47명의 환자를 대상으로 하였다. 다양한 종양형태와 크기를 고려하여 다중호형 또는 입체조형정위방사선치료를 선택하였다. 각 치료기법에 따른 회전중심점의 오차를 계산하였다. 다중호형과 입체조형정위방사선치료의 공간적 편차값($\Delta$r)은 각각 0.41 mm와 0.54 mm이었다. 다중호형정위방사선치료에서의 회전중심점의 정확도는 x, y, z 방향에서 각각 0.2 mm (SD 0.2 mm), 0.2 mm (SD 0.2), 0.3 mm (SD 0.2 mm)이었고, 입체조형정위방사선치료에서는 각각 0.2 mm (SD 0.2 mm), 0.3 mm (0.2 mm), 0.4 mm (SD 0.2 mm)이었다. 무고정틀 정위방사선치료를 이용한 회전중심점의 오차는 다중호형기법과 입체조형기법간에 차이가 없었다.