Patients Setup Verification Tool for RT (PSVTS) : DRR, Simulation, Portal and Digital images

방사선치료 시 환자자세 검증을 위한 분석용 도구 개발

  • Lee Suk (Department of Medical Physics, Kyonggi University) ;
  • Seong Jinsil (Brain Korea 21 Project for Medical Science) ;
  • Kwon Soo I1 (Department of Medical Physics, Kyonggi University) ;
  • Chu Sung Sil (Department of Radiation Oncology, Collage of Medicine, Yonsei University) ;
  • Lee Chang Geol (Department of Radiation Oncology, Collage of Medicine, Yonsei University) ;
  • Suh Chang Ok (Department of Radiation Oncology, Collage of Medicine, Yonsei University)
  • 이석 (경기대학교 대학원 의학물리학과) ;
  • 성진실 (Brain Korea 21 의과학사업단) ;
  • 권수일 (경기대학교 대학원 의학물리학과) ;
  • 추성실 (연세대학교 의과대학 방사선종양학교실) ;
  • 이창걸 (연세대학교 의과대학 방사선종양학교실) ;
  • 서창옥 (연세대학교 의과대학 방사선종양학교실)
  • Published : 2003.03.01

Abstract

Purpose : To develop a patients' setup verification tool (PSVT) to verify the alignment of the machine and the target isocenters, and the reproduclbility of patients' setup for three dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT). The utilization of this system is evaluated through phantom and patient case studies. Materials and methods : We developed and clinically tested a new method for patients' setup verification, using digitally reconstructed radiography (DRR), simulation, porial and digital images. The PSVT system was networked to a Pentium PC for the transmission of the acquired images to the PC for analysis. To verify the alignment of the machine and target isocenters, orthogonal pairs of simulation images were used as verification images. Errors in the isocenter alignment were measured by comparing the verification images with DRR of CT Images. Orthogonal films were taken of all the patients once a week. These verification films were compared with the DRR were used for the treatment setup. By performing this procedure every treatment, using humanoid phantom and patient cases, the errors of localization can be analyzed, with adjustments made from the translation. The reproducibility of the patients' setup was verified using portal and digital images. Results : The PSVT system was developed to verify the alignment of the machine and the target isocenters, and the reproducibility of the patients' setup for 3DCRT and IMRT. The results show that the localization errors are 0.8$\pm$0.2 mm (AP) and 1.0$\pm$0.3 mm (Lateral) in the cases relating to the brain and 1.1$\pm$0.5 mm (AP) and 1.0$\pm$0.6 mm (Lateral) in the cases relating to the pelvis. The reproducibility of the patients' setup was verified by visualization, using real-time image acquisition, leading to the practical utilization of our software Conclusions : A PSVT system was developed for the verification of the alignment between machine and the target isocenters, and the reproduclbility of the patients' setup in 3DCRT and IMRT. With adjustment of the completed GUI-based algorithm, and a good quality DRR image, our software may be used for clinical applications.

References

  1. ICRU Report 50: Prescribing, Recording and Reporting Photon Beam Therapy. International Commission in Radiation Units and Measurements, Bethesda, MD (1993)
  2. Sirois LM, Hristov DH, Fallone BG. Three-dimensional anatomy setup verification by correlation of orthogonal portal images and digitally reconstructed radiographs. Med Phys 1999;26:2422-2428 https://doi.org/10.1118/1.598760
  3. Hashimoto S, Shirato H, Nishioka T, et al. Remote verification in radiotherapy using digitally reconstructed radiography (DRR) and portal images: a pilot study. Int J Radiat Oncol Biol Phys 2001;50:579-585 https://doi.org/10.1016/S0360-3016(01)01485-7
  4. S Lee, DH Lee, MS Kim et al. On-line setup verification for fractionated stereotactic radiotherapy (FSRT) using electronic portal imaging device (EPID) system: DRR, simulation image vs. portal image. Int J Radiat Oncol Biol Phys 2000:48:344
  5. Hatherly KE, Smylie JC, Rodger A, et al. A double exposed portal image comparison between electronic portal imaging hard copies and port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center. Int J Radiat Oncol Biol Phys 2001;49:191-198 https://doi.org/10.1016/S0360-3016(00)00789-6
  6. Hatherly KE, Smylie J, Rodger A. A comparison of fieldonly electronic portal imaging hard copies with double exposed port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center. Int J Radiat Oncol Biol Phys 1999;45:791-796 https://doi.org/10.1016/S0360-3016(99)00249-7
  7. Herman MG, Abrams RA, Mayer RR. Clinical use of on-line portal imaging for daily patient treatment verification. Int J Radiat Oncol Biol Phys 1994;28:1017-1023 https://doi.org/10.1016/0360-3016(94)90123-6
  8. See A, Kron T, Johansen J, et al. Decision-making models in the analysis of portal films: a clinical pilot study. Australasian Radiology 2000;44:72-83 https://doi.org/10.1046/j.1440-1673.2000.00775.x
  9. Boxwala AA, Chaney EL, Fritsch DS, et al. Comparison of computer workstation with light box for detecting setup errors from portal images. Int J Radiat Oncol Biol Phys 1999;44:711-716 https://doi.org/10.1016/S0360-3016(99)00050-4
  10. Hilt G, Wolf D, Aletli P. Preprocessing of control portal images for patient setup verification during the treatments in external radiotherapy. Med Phys 1999;26:2539-2549 https://doi.org/10.1118/1.598791
  11. Gilhuijs KA, Vijlbrief RE. Optimization of automatic portal image analysis. Med Phys 1995;22:1089-1099 https://doi.org/10.1118/1.597610
  12. S Lee, BY Yi, JG Cho, et al. Geometrical QC/QA for medical linear accelerator using electronic portal imaging device (EPID). Korean Journal of Medical Physics 1997;8:59-65
  13. ohnson LS, Miliken BD, Hadley SW, et al. Initial clinical experience with a video-based patient positioning system. Int J Radiat Oncol Biol Phys 1999;45:205-213
  14. Zhu Y, Jiang XQ, van Dyk J. Portal dosimetry using a liquid ion chamber matrix: dose response studies. Med Phys 1995;22:1101-1106 https://doi.org/10.1118/1.597502
  15. Luchka K, Chen D, Shalev S. Assessing radiation and light field congruence with a video based electronic portal imaging device. Med Phys 1996;23:1245-1252 https://doi.org/10.1118/1.597867
  16. S Lee, HS Chang, EK Choi et al. On-line quality assurance of linear accelerator with electronic portal imaging system. Med Phys 1998;25:1582
  17. Curtin-Savard A, Podgorsak EB. An electronic portal imaging device as a physics tool. Medical Dosimetry 1997;22:101-105 https://doi.org/10.1016/S0958-3947(97)00002-2
  18. 조병철, 오도훈, 배훈식. 디지털화재구성사진(Digitally Reconstructed Radiograph)을 이용한 정위방사선수술 및 치료의 치료위치 확인. 대한방사선종약학회지 1999;17:84-88
  19. Siddon RL. Fast calculation of the exact radiological path for a three-dimensional CT array. Med Phys 1985;12:138-144
  20. Gilhuijs KGA, van de Ven PJH, van Herk M. Automatic three-dimensional inspection of patient setup in radiation therapy using portal images, simulator images, and computed tomography data. Med Phys 1996;23:389-399 https://doi.org/10.1118/1.597801
  21. Lujan A, Balter M, Haken RK. Determination of rotations in three dimensions using two-dimensional portal image registration. Med Phys 1998;25:703-708 https://doi.org/10.1118/1.598253
  22. Lemieux L, Kitchen ND, Thomas DGT. A patient-tocomputed tomography image registration method based on digitally reconstructed radiographs. Med Phys 1994;21:1749-1760 https://doi.org/10.1118/1.597276
  23. Hristov DH, Fallone BG. A grey-level image alignment algorithm for registration of portal images and digitally reconstructed radiographs. Med Phys 1996;23:75-84 https://doi.org/10.1118/1.597743
  24. Hendee WR, Trueblood JH. Digital Imaging. American Association of Physicists in Medicine by Medical Physics Publishing Corporation, 1993:195-280