Radiation Oncology Journal

The Korean Society for Radiation Oncology (대한방사선종양학회)
권호 표지

Development of Conformal Radiotherapy with Respiratory Gate Device

호흡주기에 따른 방사선입체조형치료법의 개발

  • Chu Sung Sil (Department of Radiation Oncology, Yonsei Cancer Center, College of Medicine, Yonsei University) ;
  • Cho Kwang Hwan (Department of Radiation Oncology, Yonsei Cancer Center, College of Medicine, Yonsei University) ;
  • Lee Chang Geol (Department of Radiation Oncology, Yonsei Cancer Center, College of Medicine, Yonsei University) ;
  • Suh Chang Ok (Department of Radiation Oncology, Yonsei Cancer Center, College of Medicine, Yonsei University)
  • 추성실 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 조광환 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 이창걸 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 서창옥 (연세대학교 의과대학 방사선종양학교실, 연세암센터)
  • Published : 2002.03.01
Download PDF
⟨ Previous Next ⟩

Abstract

Purpose : 3D conformal radiotherapy, the optimum dose delivered to the tumor and provided the risk of normal tissue unless marginal miss, was restricted by organ motion. For tumors in the thorax and abdomen, the planning target volume (PTV) is decided including the margin for movement of tumor volumes during treatment due to patients breathing. We designed the respiratory gating radiotherapy device (RGRD) for using during CT simulation, dose planning and beam delivery at identical breathing period conditions. Using RGRD, reducing the treatment margin for organ (thorax or abdomen) motion due to breathing and improve dose distribution for 3D conformal radiotherapy. Materials and Methods : The internal organ motion data for lung cancer patients were obtained by examining the diaphragm in the supine position to find the position dependency. We made a respiratory gating radiotherapy device (RGRD) that is composed of a strip band, drug sensor, micro switch, and a connected on-off switch in a LINAC control box. During same breathing period by RGRD, spiral CT scan, virtual simulation, and 3D dose planing for lung cancer patients were peformed, without an extended PTV margin for free breathing, and then the dose was delivered at the same positions. We calculated effective volumes and normal tissue complication probabilities (NTCP) using dose volume histograms for normal lung, and analyzed changes in doses associated with selected NTCP levels and tumor control probabilities (TCP) at these new dose levels. The effects of 3D conformal radiotherapy by RGRD were evaluated with DVH (Dose Volume Histogram), TCP, NTCP and dose statistics. Results : The average movement of a diaphragm was 1.5 cm in the supine position when patients breathed freely. Depending on the location of the tumor, the magnitude of the PTV margin needs to be extended from 1 cm to 3 cm, which can greatly increase normal tissue irradiation, and hence, results in increase of the normal tissue complications probabiliy. Simple and precise RGRD is very easy to setup on patients and is sensitive to length variation (+2 mm), it also delivers on-off information to patients and the LINAC machine. We evaluated the treatment plans of patients who had received conformal partial organ lung irradiation for the treatment of thorax malignancies. Using RGRD, the PTV margin by free breathing can be reduced about 2 cm for moving organs by breathing. TCP values are almost the same values $(4\~5\%\;increased)$ for lung cancer regardless of increasing the PTV margin to 2.0 cm but NTCP values are rapidly increased $(50\~70\%\;increased)$ for upon extending PTV margins by 2.0 cm. Conclusion : Internal organ motion due to breathing can be reduced effectively using our simple RGRD. This method can be used in clinical treatments to reduce organ motion induced margin, thereby reducing normal tissue irradiation. Using treatment planning software, the dose to normal tissues was analyzed by comparing dose statistics with and without RGRD. Potential benefits of radiotherapy derived from reduction or elimination of planning target volume (PTV) margins associated with patient breathing through the evaluation of the lung cancer patients treated with 3D conformal radiotherapy.

목적 : 호흡주기에 따른 위치변동 감지센서를 이용하여 종양의 위치가 일정워치에 있을 때만 방사선을 치료하는 호흡 동기치료기구를 제작하고 일정한 호흡주기 상태에서 수행된 CT simulation과 3차원 입체조형치료계획에 따라 방사선을 치료하는 시스템을 개발하고자 하였다. 호흡유무에 따른 종양의 치료 마진(margin)을 측정하고 계획용표적체적(planning target volume:PTV)의 크기에 따른 선량체적표(dose volume histogram:DVH)와 종양억제확률(tumor control probability:NTCP), 건강조직손상확률(normal tissue complication probability:NTCP) 및 선량 통계자료를 통하여 치료성과를 평가하고 선량증강 범위를 예측하고자 하였다. 대상 및 방법 : 종양이 비교적 작고 전이가 없는(T1N0M0) 5명의 폐암환자를 선택하여 X-선 조준장치를 이용하여 횡격막의 이동거리를 측정하는 방법으로 내부장기의 운동을 평가하였다. 호흡동기치료기구는 끌어당김 센서가 부착된 허리띠 모양으로 구성되었으며 이를 흉곽 또는 복부에 부착하여 호흡주기에 의한 흉곽의 크기변동에 따라 센서의 회로가 개폐되고 이것을 선형가속기의 조종간에 연결하는 간단한 기구로서 감도와 재현성이 높았다. 호흡을 배기한 후 일시적 호흡이 정지된 상태에서 Spiral-CT (PQ-5000)로 3차원 영상을 획득하고 Virtual CT-simulator (AcQ-SIM)에 의하여 종양의 위치와 주위 장기들을 확인 도시하였으며 3차원 치료계획장치(Pinnacle, ADAC Co.)를 이용하여 3차원 입체조형치료를 계획하였다. 치료계획의 평가는 호흡동기치료기구의 사용유무에 따른 PTV의 크기에 따라 최적 선량분포를 구사하였으며 각각의 DVH, TCP, NTCP 및 선량통계자료를 도출 비교 검토하였다. 결과 : X-선 simulation에서 폐암환자의 횡격막 이동은 약 1 cm에서 2.5 cm로서 평균 1.5 cm로 측정되었고 자유호흡시 PTV는 CTV (clinical target volume)에 약 2 cm 마진을 주었으며 호흡동기치료기구를 사용하였을 때는 0.5 cm 마진이 적당한 것으로 측정되었다. 종양의 PTV는 연장 마진의 거의 자승비로 증가하였으며 TCP의 값은 마진 범위 $(0.5\~2.0\;cm)$에 관계없이 거의 일정하였고 NTCP의 값은 마진 크기에 따라 평균 $65\%$로 급속히 증가하였다. 결론 : 호흡주기에 따른 위치변동 감지센서를 이용한 호흡동기치료기구는 종양의 위치가 일정할 때만 방사선이 조사되는 간단하고 정확한 장치로서 3차원 입체조형치료 및 강도변조방사선치료에서 매우 유용한 장치임을 확인할 수 있었다. 또한 호흡조절 방사선입체조형치료방법의 기술과 시술절차를 확립시키고 정량적인 선량평가를 위하여 DVH, TCP, NTCP 등의 정량분석과 종양의 투여 선량 증가량(dose escalation)을 예측하는 기초자료를 제공할 수 있었다.

Keywords

References

  1. Webb S. Optimization of conformal radiotherapy dose distributions by simulated annealing. Phys Med Biol 1989;34:1349-1379 https://doi.org/10.1088/0031-9155/34/10/002
  2. Mohan R, Leibel S, Burman CM, Fuks Z, Mageras GS. Clinically relevant optimization of 3- dimensional conformaltreatments. Med Phy 1992;19:933-944 https://doi.org/10.1118/1.596781
  3. Michalski JM, Sur RK, Harms WB, Purdy JA. Three dimensional conformal radiation therapy in pediatric parameningeal rhabdomyosarcomsa. Int J Radiol Oncol Biol Phys 1995;33:985-991 https://doi.org/10.1016/0360-3016(95)00551-X
  4. Webb S. Optimizing the planning of intensity modulated radiotherapy. Phy Med Biol 1994;39:2229-2246 https://doi.org/10.1088/0031-9155/39/12/007
  5. Emami B, Lyman J, Brown A, et al. Tolerance of normaltissue to therapeutic radiation. Int J Radiat Oncol Biol Phys 1991;21:109-122
  6. Ling CC, Burman C, Chui CS, et al. Perspectives of multidimensional conformal radiation treatment. Radioth Oncol 1993;29:129-139 https://doi.org/10.1016/0167-8140(93)90238-4
  7. Emami B, Purdy JA, Manolis J. Tree dimensional treatment planning for lung cancer. Int J Rad Oncol Biol Phys 1991;21:217-227 https://doi.org/10.1016/0360-3016(91)90180-C
  8. Ramsey CR, Scaperoth D, Arwood D, et al. Clinical efficacy of respiratory gated conformal radiation therapy. Med Dosi 1999;24:115-119 https://doi.org/10.1016/S0958-3947(99)00006-0
  9. Kubo HD, Len PM, Minohara S, et al. Breathing synchronized radiotheraqy progam at the university of californiadavs cancer center. Med Phys 2000;27:346-353 https://doi.org/10.1118/1.598837
  10. Wong JW, Sharpe MB, Jaffraty DA, et al. The use of active breathing control (ABC) to reduce margin for breathingmotion. Int J Rad Oncol Biol Phys 1999;44:911-919 https://doi.org/10.1016/S0360-3016(99)00056-5
  11. Mah D, Hanley J, Rosenzweig KE, et al. Technicsal aspects of the deep inspiration breath hold technique in the treatment of thoracic cancer. Int J Rad Oncol Biol Phys 2000;48:1175-1185 https://doi.org/10.1016/S0360-3016(00)00747-1
  12. Kim DJW, Murray BR, Halperin R, et al. Held breath selfgating technique for radiotherapy of non small cell Iung cancer : A feasibility study. Int J Red Oncol Biol Phys 2001;49:43-49 https://doi.org/10.1016/S0360-3016(00)01372-9
  13. Shirato H, Shimizu S, Herk MV, et al. Physical aspects of a real time time tumor tumor tracking system for gated radiotherapy. Int J Rad Oncol Biol Phys 2000;48;1187-1195
  14. Minohara S, Kanai T, Endo M, et al. Respiratory gatedirradiation system for heavy ion radiotherapy. Int J Rad Oncol Biol Phys 2000;47:1097-1103 https://doi.org/10.1016/S0360-3016(00)00524-1
  15. Rosenzweig KE, Sim SE, Mychalczak B, et al. Electivenodal irradiation in the treatment of non small cell Iung cancer with three dimensional conformal radiation therapy. Int J Rad Oncol Biol Phys 2001;50:681-685 https://doi.org/10.1016/S0360-3016(01)01482-1
  16. Willett CG, Linggood RM, Stracher MA, et al. The effects of the respiratory cycle on mediastinal and lung dimensions in hodgkin's disease. lmplications for radiotherapy gated to respiration. Cancer 1987;60:1232-1237 https://doi.org/10.1002/1097-0142(19870915)60:6<1232::AID-CNCR2820600612>3.0.CO;2-F
  17. Henkelman RM, Mah K. How important is breathing in radiation therapy of the thiorax. Int J Radiat Oncol Biol Phys 1982:8;2005-2010
  18. Korin HW, Ehman RL, et al. Respiratory kinematics of the upper abdominal organe : A quantitve study. Magn Reson Med 1992;23:172-178 https://doi.org/10.1002/mrm.1910230118
  19. Kubo HD, Hill BC. Respirarion gated radiotherapy treatment : A technical study. Phys Med Biol 1996;41:83-91 https://doi.org/10.1088/0031-9155/41/1/007
  20. Mori M, Murata K, Takahashi M, et al. Accurate comtiguous sections without brearh-holding on chest CT: Value of respiratory gating and ultrafst CT. AJR 1994;162:1057-1062 https://doi.org/10.2214/ajr.162.5.8165981
  21. John WW, Michael BS, David AJ, et al. The use of active breathing control (ABC) to reduce margin for breathingmotion. Int J Radiat Oncol Biol Phys 1999;44:911-919 https://doi.org/10.1016/S0360-3016(99)00056-5
  22. Rardall KT, James MB, et al. Potential benefits of eliminating planning target volume expansions for patient breathing in the treatment of liver tumors, Int J Radiat Oncol Biol Phys 1997;38:613-617
  23. Mageras GS, Kutcher GJ, Leibel SA, et al. A method of incorporating organ motion uncertainties into three-dimensional conformal treatment plans. Int J Radiat Oncol Biol Phys 1996;35:333-342 https://doi.org/10.1016/0360-3016(96)00008-9
  24. Yu CX, Wong JW. The effects of intra-treatment organ motion on the delivery of dynamic intensity modulation. Phys Med Biol 1998;43:91-104 https://doi.org/10.1088/0031-9155/43/1/006
  25. Brahme A. Dosimetric precision requirements in radiationtherapy. Acta Radiol Oncol 1984;23:379-391 https://doi.org/10.3109/02841868409136037
  26. Niemierko A, Goitein M. Cslculation of normal tissue complication probability and dose volume histogram reductionschemes for tisues with a critical element architecture. Rad Ther Oncol 1991;20:166-176 https://doi.org/10.1016/0167-8140(91)90093-V
  27. Lyman JT. Complication probabilities as assessed from dosevolume histograms. Rad Res 1985;104:513-519
  28. Powlis WD, Altshuler MD. Semi automated radiotherapytreatment planning wih a mathematical model to satisfy treatment goals. Int J Radiat Oncol Biol Phys 1989;16:271-276 https://doi.org/10.1016/0360-3016(89)90042-4
  29. Vitali M, Jerry B, and Jake VD. Normal tissue complication probabilities : Dependence on choice of biological model and dose-volume histogram reduction scheme. Int J Radiat Oncol Biol Phys 2000;46:983-993 https://doi.org/10.1016/S0360-3016(99)00473-3
  30. Schultheiss TE, Orton CG, Peck RA. Models in radiotherapy : Volume effect. Med Phy 1983;10:410-415 https://doi.org/10.1118/1.595312
  31. Wither HR, Taylor JM, Maciejewski B. Treatment volume and tissue tolerance. Int J Radiat Oncol Biol Phys 1988;14:751-759 https://doi.org/10.1016/0360-3016(88)90098-3
  32. Wolbarst AB, Chin LM, Svensson GK. Optimization of radiation therapy. Int J Radiat Oncol Biol Phys 1988;14:751-759 https://doi.org/10.1016/0360-3016(88)90098-3
  33. Drzymala RE, Mohan RE, Brewster L, et al. Dose volume histograms. Int J Radiat Oncol Biol Phys 1991;21:71-78 https://doi.org/10.1016/0360-3016(91)90168-4
  34. Lyman JT, Wolbarst AB. Optimization of radiotherapy. lll. Amethod for assessing complication of radiotherapy. lll. A method for assessing complication probability from dose volume histograms. Int J Radiat Oncol Biol Phys 1987;13:103-109
  35. Kutcher GJ, Burman C. Calculation of complication probability factors for non-uniform normal tissue irradiation : The effective volume method. Int J Radiat Oncol Biol Phys 1989;6:1623-1630
  36. Burman C, Kutcher GJ, Emami B, Goiten M. Fitting of normal tissue tolerance data to an analytic function. Int J Radiat Oncol Biol Phys 1991;21:123-135
  37. Brahme A. Design principles and clinical possibilities with a new generation of radiation therapy equipment. Acta Oncol 1987;26:403-412 https://doi.org/10.3109/02841868709113708
  38. Tepper JE. 3-D display in planning radiation therapy. Int J Radiat Oncol Biol Phy 1991;21:79-89 https://doi.org/10.1016/0360-3016(91)90169-5