Journal of radiological science and technology (대한방사선기술학회지:방사선기술과학)

Korean Society of Radiological Science (대한방사선과학회)
권호 표지
DOI QR코드

DOI QR Code

The Effect of Patients Positioning System on the Prescription Dose in Radiation Therapy

방사선치료 시 자세확인시스템이 처방선량에 미치는 영향

  • Kim, Jeong-Ho (Department of Radiation Oncology, Konyang University Hospital) ;
  • Bae, Seok-Hwan (Department of Radiological Science, Konyang University)
  • 김정호 (건양대학교병원 방사선종양학과) ;
  • 배석환 (건양대학교 방사선학과)
  • Received : 2017.08.21
  • Accepted : 2017.12.19
  • Published : 2017.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

Planning dose must be delivered accurately for radiation therapy. Also, It must be needed accurately setup. However, patient positioning images were need for accuracy setup. Then patient positioning images is followed by additional exposure to radiation. For 45 points in the phantom, we measured the doses for 6 MV and 10 MV photon beams, OBI(On Board Imager) and CBCT(Conebeam Computed Tomography) using OSLD(Optically Stimulated Luminescent Dosimeter). We compared the differences in the cases where posture confirmation imaging at each point was added to the treatment dose. Also, we tried to propose a photography cycle that satisfies the 5% recommended by AAPM(The American Association of Physicists in Medicine). As a result, a maximum of 98.6 cGy was obtained at a minimum of 45.27 cGy at the 6 MV, a maximum of 99.66 cGy at a minimum of 53.34 cGy at the 10 MV, a maximum of 2.64 cGy at the minimum of 0.19 cGy for the OBI and a maximum of 17.18 cGy at the minimum of 0.54 cGy for the CBCT.The ratio of the radiation dose to the treatment dose is 3.49% in the case of 2D imaging and the maximum is 22.65% in the case of 3D imaging. Therefore, tolerance of 2D image is 1 exposure per day, and 3D image is 1 exposure per week. And it is need to calculation of separate in the parallelism at additional study.

방사선치료 시 치료계획 선량의 정확한 전달이 중요하다. 뿐만 아니라 정확한 자세 잡이도 필요하다. 하지만 정확한 자세 잡이를 위해서는 자세촬영을 실시하여야 하며 이에 따른 추가적인 방사선 피폭이 발생하게 된다. 이에 자세촬영 주기에 따른 선량분포의 변화를 분석하고자 한다. 팬텀 내 45개 지점에 대해 OSLD를 이용하여 6MV와 10MV 광자선, 그리고 온보드이미지촬영과 콘빔전산화단층촬영에 대한 선량을 측정하였다. 그리고 각 지점에 대한 자세확인촬영이 치료선량에 합산될 경우의 차이값을 비교하였다. 또한 차이값이 미국의학물리협회에서 권고하는 5%를 만족하는 촬영 주기를 제시하고자 하였다. 그 결과 6MV에서는 최소 45.27 cGy에서 최대 98.6 cGy, 10MV에서는 최소 53.34 cGy에서 최대 99.66 cGy, 온보드이미지촬영의 경우 최소 0.19 cGy에서 최대 2.64 cGy, 콘빔전산화단층촬영의 경우 최소 0.54 cGy에서 최대 17.18 cGy가 측정되었다. 치료선량에 대한 자세확인촬영 방사선량의 비율은 2차원 영상의 경우 치료 1회당 최대 3.49%, 3차원 영상의 경우 치료 1회당 최대 22.65%의 오차가 발생된다. 따라서 2차원 영상은 1일 1회, 3차원 영상은 1주 1회까지 허용된다. 향후 추가연구 시 실제 임상적용 시에는 환자자세촬영 종류의 병행에 대한 분리계산이 필요하리라 사료된다.

Keywords

References

  1. E. S. Jang, S. M. Beak, S. J. Ko, et al., A Study for Advanced Radiation Therapy. J of Korean Radiothera Tech. 2008; 20(2):115-122.
  2. R. G. Dale, The application of the linear quadratic dose effect equation to fractionated and protracted radiotherapy. British Journal of Radiology. 1985; 58(1): 515-528. https://doi.org/10.1259/0007-1285-58-690-515
  3. P. K. Kartha, A. Chung-Bin, T. Wachtor, et al., Accuracy in radiotherapy treatment. International Journal of Radiation Oncology*Biology* Physics. 1977; 2(7):797-799. https://doi.org/10.1016/0360-3016(77)90066-9
  4. B. Thomas, "IMRT: a review and preview.", Physics in medicine and biology. 2006; 51(13):363. https://doi.org/10.1088/0031-9155/51/13/R21
  5. M. Stasi, S. Bresciani, A. Miranti, et al., Pretreatment patient-specific IMRT quality assurance: a correlation study between gamma index and patient clinical dose volume histogram. Medical physics. 2012; 39(12):7626-7634. https://doi.org/10.1118/1.4767763
  6. B. Warkentin, S. Steciw, S. Rathee, et al., Dosimetric IMRT verification with a flat-panel EPID. Medical physics. 2003;30(12):3143-3155. https://doi.org/10.1118/1.1625440
  7. M. Partridge, M. Ebert, & B. M. Hesse, IMRT verification by three-dimensional dose reconstruction from portal beam measurements. Medical physics. 2002;29(8) 1847-1858. https://doi.org/10.1118/1.1494988
  8. R. C. Gilson, M. P. Catherine, & T. G. Robert., Bullous Pseudomonas skin infection and bacteremia caused by tattoo ink used in radiation therapy. JAAD Case Reports. 2015;4:222-224.
  9. Y. C. Ahn, S. G. Ju, D. Y. Kim, et al., Design and development of new collimator cones for fractionated stereotactic radiation therapy in Samsung Medical Center. International Journal of Radiation Oncology Biology Physics. 1999;44(2):435-438. https://doi.org/10.1016/S0360-3016(99)00005-X
  10. Hammoud, R., Michigan, B., On-board imaging system: implementation and quality assurance procedures. In Lecture presented at the 49th AAPM Annual Meeting. 2016; 1-120.
  11. B. Sorcini, A. Tilikidis, Clinical application of image-guided radiotherapy, IGRT (on the Varian OBI platform). CancerCRadiothCrapie. 2006;10(5):252-257. https://doi.org/10.1016/j.canrad.2006.05.012
  12. C. Huntzinger, P. Munro, S. Johnson, et al., Dynamic targeting image-guided radiotherapy. Medical Dosimetry. 2006;31(2):113-125. https://doi.org/10.1016/j.meddos.2005.12.014
  13. B. J. M. Heijmen, K. L. Pasma, M. Kroonwijk, et al., Portal dose measurement in radiotherapy using an electronic portal imaging device (EPID). Physics in medicine and biology. 1995;40(11):1943. https://doi.org/10.1088/0031-9155/40/11/012
  14. K. R. Britton, Y. Takai, M. Mitsuya, et al., Evaluation of inter-and intrafraction organ motion during intensity modulated radiation therapy (IMRT) for localized prostate cancer measured by a newly developed on-board image-guided system. Radiation medicine. 2005;23(1):14-24.
  15. T. Bortfeld, K. Jokivarsi, M. Goitein, et al., Effects of intra-fraction motion on IMRT dose delivery: statistical analysis and simulation. Physics in medicine and biology. 2002;47(13):2203. https://doi.org/10.1088/0031-9155/47/13/302
  16. W. Y. Song, S. Kamath, S. Ozawa, et al., A dose comparison study between XVI(R) and OBI(R) CBCT systems. Medical physics. 2008;35(2):480-486. https://doi.org/10.1118/1.2825619
  17. A. Palm, E. Nilsson, & L. Herrnsdorf, Absorbed dose and dose rate using the Varian OBI 1.3 and 1.4 CBCT system. Journal of applied clinical medical physics. 2010;11(1):229-240. https://doi.org/10.1120/jacmp.v11i1.3085
  18. D. W. Kim, W. K. Chung, M. Yoon, et al., Imaging doses and secondary cancer risk from kilovoltage cone-beam CT in radiation therapy. Health physics. 2013;104( 5):499-503. https://doi.org/10.1097/HP.0b013e318285c685
  19. H. S. Kim, A study on the direction and energy dependency of personal exposure dosimeter for medical x-ray irradiation. Ph.D. thesis, Chosun University, 2013.
  20. J. M. Kim, S. D. Cheon, G. M. Beak, et al., Characteristic Evaluation of Optically Stimulated Luminescent Dosimeter (OSLD) for Dosimetry. Journal of Korean Society for Radiation Therapy. 2010;.22(2):123-129.
  21. B. R. Yoon, M. L. Hong, J. H. Ahn, et al., Compare to Evaluate the Imaging dose of MVCT and CBCT. Journal of Korean Society for Radiation Therapy. 2014;26(1): 83-89.
  22. B. K. Lee, S. M. Kang, Extra Dose Measurement of Differential Slice Thickness of MVCT Image with Helical Tomotherapy. Journal of the Korean Society of Radiology. 2013;7(2):145-149. https://doi.org/10.7742/jksr.2013.7.2.145