A Study of the Adjustment and Treatment Depending on the Change of Prostate Location Using DIPS in Proton Beam Therapy for Prostate Gland in which a Fiducial Gold Marker was Inserted

국문 초록 (Abstract)

목 적: Fiducial Gold Marker가 삽입된 전립선암 양성자 치료 시 DIPS를 이용하여 전립선의 위치변화를 관찰하고, 전립선의 움직임에 따른 보정 및 양성자치료에 관한 연구를 하고자 한다. 대상 및 방법: 2008년 4월 이후로 본원에서 양성자치료를 받은 10명의 전립선암환자를 대상으로 하였다. 전립선의 위치변화를 관찰하기위해 치료 전에 전립선에 3개의 Fiducial Gold Marker를 삽입하였고, 전립선의 움직임을 최소화하기 위해 치료 전에 소변을 보고, 매일 정량의 물을 섭취하며, Rectal balloon을 함께 시행하였다. 환자의 처음 치료자세는 CT 모의치료 때와 같고, DIPS (Digital Image Positioning System)를 이용하여 AP, Lat 촬영을 하여 얻은 영상과 치료계획에서 얻은 PA, Lat 영상을 비교하여, Fiducial Gold Marker 위치변화(X, Y, Z) 관찰하였고, 이에 따른 보정 후에 양성자치료를 시행하였다. 결 과: 치료계획에서 얻은 영상과 DIPS를 이용하여 얻은 영상의 각각의 Fiducial Gold Marker의 위치변화 차이는 10명 환자에 있어서 치료 중심을 기준으로 평균 X축: $\pm$0.116 cm, Y축: $\pm$0.19 cm, Z축: $\pm$0.176 cm이었다. 10명의 환자 중 X축으로 최고 RT: 0.24 cm, 최저 RT: 0.04 cm의 위치변화 차이가 나타났고, Y축으로 최고 Sup: 0.42 cm, 최저 Inf: 0.03 cm 위치변화 차이가 나타났고, Z축으로 최고 Ant: 0.35 cm, 최저 Post: 0.05 cm의 위치변화 차이가 관찰되었다. 결 론: 전립선의 움직임을 최소화 하기위해 치료 전에 전처치로 소변을 보고, 매일 정량의 물을 섭취하며, Rectal balloon을 시행하였으나, 모든 환자의 경우에서 전립선에 삽입된 3개의 Fiducial Gold Marker의 매일 움직임을 관찰할 수 있었다. 위 자료를 바탕으로 보다 정확한 치료 중심 설정이 요구되는 양성자치료에서 Gold Marker Matching System의 필요성을 확인할 수 있었으며, 본 연구에서 사용된 DIPS를 이용하여 전립선의 위치변화에 따른 치료 중심을 보정함으로써 보다 정밀한 양성자치료 효과를 향상시킬 수 있을 것으로 사료된다.

다국어 초록 (Multilingual Abstract)

Purpose: To monitor the changes of location of prostate gland using DIPS and to examine the adjustment and proton beam therapy depending on the movement of prostate gland in proton beam therapy for prostate gland in which a fiducial gold marker was inserted. Materials and Methods: This study was conducted in ten patients with prostate cancer who received proton beam therapy since April of 2008. To monitor the change of prostate location, three fiducial gold markers were inserted prior to the treatment. To minimize the movement of prostate gland, patients were recommended to urinate prior to the treatment, to intake a certain amount of water and to concomitantly undergo rectal balloon. In these patients, the set-up position was identical to that for a CT-simulation. The PA (posterior-anterior) and lateral images were obtained using both DIPS (digital image positioning system) and a plain radiography, and they were compared between the two imaging modalities. Thus, the changes of the location of fiducial gold marker were assessed based on three coordinates (x, y, z) and then adjusted. This was followed by proton beam therapy. Results: Images which were taken using a plain radiography were compared with those which were taken using DIPS. In ten patients, according to a reference bony marker, the mean changes of the location of fiducial gold marker based on an iso-center were X-axis: $\pm$0.116 cm, Y-axis: $\pm$0.19 cm and Z-axis: $\pm$0.176 cm. These ten patients showed a difference in the changes of location of prostate gland and it ranged between RT: 0.04 cm and RT: 0.24 cm on the X-axis; between Inf: 0.03 cm and Sup: 0.42 cm on the Y-axis; and Post: 0.05 cm and Ant: 0.35 cm on the Z-axis. Conclusion: To minimize the movement of prostate gland, as the pre-treatment prior to the treatment. In all the patients, however, three fiducial gold markers showed a daily variation which were inserted in the prostate gland. Based on the above data, Thus, the requirement of gold marker matching system depending on the daily variation in the proton beam therapy for which more accurate establishment of target was confirmed. It is assumed that an accurate effect of proton beam therapy would be enhanced by adjusting the target-center depending on the location change of prostate gland using DIPS which was used in the current study.