The Journal of the Korea Contents Association (한국콘텐츠학회논문지)

The Korea Contents Association (한국콘텐츠학회)
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An Efficient Correction Process of CT-Simulator Couch with Current Diagnostic CT Scanners

진단용 CT-모의치료기 테이블의 효율적인 교정 방법

  • 구은회 (순천향대학교 물리학과) ;
  • 이재승 (순천향대학교 물리학과) ;
  • 조정근 (전주대학교 방사선학과) ;
  • 문성권 (순천향대학교 부천병원 방사선종양학과)
  • Published : 2009.11.28
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Abstract

This study suggested that the table of CT-simulator and the laser alignment system using diagnostic CT scanner have an efficient method for improvement in alignment between the planned target center of traverse image with CT scanner. It was conducted on the daily QA when presented in the AAPM TG66 with correcting the laser alignment system using geometric trigonometric functions and investigated the effectiveness of correction methods as compared with those before and after correction. Before correction error was 3.82mm between the planned target center of image, the table longitudinal axis was twisted with 0.436o. The laser alignment system using geometric trigonometric functions in after correction was satisfied with tolerance limits of ${\pm}2mm$ when occurred about 0.7mm in errors between the planned target center. The table correction to satisfy the geometric accuracy is very inefficient over against the time and economic loss as well as technical limits in the case of application as only radiation therapy associated with CT-simulator with diagnostic CT scanner in use. But, the method which corrects the laser alignment system is economic and relatively simple with possibility of getting well geometric accuracy and we suppose that it is efficient method for applying in the clinic.

본 연구는 진단용 CT 장치를 이용한 CT-모의치료기의 테이블 및 레이저 정렬 시스템과 횡단면 영상의 중심간 정렬을 개선하기 위한 효율적인 방법을 제안하고자 하였다. 본원에서 제작한 팬텀을 이용하여 AAPM TG66에서 제시하는 일일 정도관리를 시행하고 기하학적 삼각함수를 이용하여 레이저 정렬 시스템을 교정하였으며 교정 전, 후를 비교함으로서 교정방법에 대한 효율성을 검토하였다. 교정 전 영상의 중심간 오차는 3.82mm, 테이블 종축은 $0.436^{\circ}$ 틀어져 진행하였다. 기하학적 삼각함수를 이용한 레이저 정렬 시스템의 교정 후 0.7mm의 중심간 오차가 발생하여 ${\pm}2mm$의 허용오차 범위를 만족하였다. 설치 가동 중인 진단용 CT 장치를 방사선치료 전용 CT-모의치료기로 활용하는 경우 기하학적 정확도를 만족시키기 위한 테이블 교정은 기술적인 한계 뿐 만 아니라 시간 및 경제적 손실에 비하여 매우 비효율적이다. 그러나 레이저 정렬 시스템을 이용한 교정 방법은 경제적이고 비교적 간단하면서도 만족스러운 기하학적 정확도를 얻을 수 있어 임상에서 적용할 수 있는 효율적인 방법이라 사료된다.

Keywords

References

  1. E. G. Aird and J. Conway, "CT simulation for radiotherapy treatment planning," Br J Radio, Vol.75, pp.937-949, 2002. https://doi.org/10.1259/bjr.75.900.750937
  2. J. Conway and M. H. Robinson, "CT virtual simulation," Br J Radio, Vol.70, Spec No:S106-S118, 1997. https://doi.org/10.1259/bjr.1997.0014
  3. G. W. Sherouse, J. D. Bourland, and K. Reynolds, "Virtual simulation in the clinical setting: some practical considerations," Int J Radiat Oncol Biol Phys, Vol,19, No.4, pp.1059-1065, 1990. https://doi.org/10.1016/0360-3016(90)90034-H
  4. T. Nishidai, Y. Nagata, and M. Takahashi, et al, "CT simulator: a new 3-D planning and simulating system for radiotherapy: Part 1. Description of system," Int J Radiat Oncol Biol Phys, Vol.18, No.3, pp.499-504, 1990. https://doi.org/10.1016/0360-3016(90)90052-L
  5. Y. Nagata, T. Nishidai, and M. Abe, et al, "CT simulator: a new 3-D planning and simulating system for radiotherapy: Part 2. Clinical application," Int J Radiat Oncol Biol Phys, Vol.18, No.3, pp.505-513, 1990. https://doi.org/10.1016/0360-3016(90)90053-M
  6. J. L. Garcia-Ramirez, S. Mutic, and J. F. Dempsey, et al, "Performance evaluation of an 85 cm bore computed tomography scanner designed for radiation oncology and compared with current diagnostic CT scanners," Int J Radiat Oncol Biol Phys, Vol.52, No.4, pp.1123-1131, 2002. https://doi.org/10.1016/S0360-3016(01)02779-1
  7. S. Mutic, J. R. Palta, and E. K. Butker, et al, "AAPM Radiation Therapy Committee Task Group No.66, Quality assurance for computed-tomography simulators and the computed tomography-simulation process: Report of the AAPM Radiation Therapy Committee Task Group No. 66," Med Phys, Vol.30, No.10, pp.2762-2792, 2003. https://doi.org/10.1118/1.1609271
  8. G. J. Kutcher, L. Coia, and M. Gillin, et al, "Comprehensive QA for radation oncology: report of AAPM Radiation Therapy Committee Task Group 40," Vol.21, No.4, pp.581-618, 1994. https://doi.org/10.1118/1.597316
  9. J Wang, Z. Wu, and C. Zhang, et al, "Enhanced digitally reconstructed radio- graphs generated by ray tracing," Sheng Wu Yi Xue Gong Cheng Xue Za Zhi, Vol.22, No.1, pp.125-128, 2005.
  10. K.P. McGee, J. J Das, and C. Sims, "Evaluation of digitally reconstructed radiographs(DRRs) used for clinical radiotherapy: a phantom study," Med Phys, Vol.22, No.11, pp.1815-1827, 1995. https://doi.org/10.1118/1.597637
  11. B. G. Fallone, C. Evans, and B. G. Clark, et al, "Verification of the correspondence between CT-simulated and treatment beams," Med Phys, Vol.25, No.12, pp.750-751, 1998. https://doi.org/10.1118/1.598256
  12. T. B. Craig, J. Brochu, and J. VanDyk, "A quality assurance phantom for three-dimensional radiation treatment planning," Int J Radiat Oncol Biol Phys, Vol.44, No.2, pp.955-966, 1999. https://doi.org/10.1016/S0360-3016(99)00070-X
  13. R. R. Liu, K. L. Prado, and M. T. Gillin, "Simplified "on-couch" daily quality assurance procedure for CT simulators," J Appl Clin Med Phys, Vol.10, No.3, pp.2844, 2009.
  14. D. Driver and H. J. Dobbs, "Improvements in radiotherapy practice: the impact of new imaging technologies," Cancer Imaging, Vol.21, No.4, pp.142-150, 2004.
  15. G. R. Baker, "Localization; conventional and CT simulation," Br J Radio, Vol.79, Spec No:S36-49, 2006. https://doi.org/10.1259/bjr/17748030