Lung RPO 선량전달시, Carbon Couch Side Rail과 Vac-lok이 미치는 영향

Effect of Carbon Couch Side Rail and Vac-lok In case of Lung RPO irradiation

  • 김석민 (전북대학교 병원 방사선종양학과) ;
  • 곽근탁 (전북대학교 병원 방사선종양학과) ;
  • 이승훈 (전북대학교 병원 방사선종양학과) ;
  • 김정수 (전북대학교 의과대학 방사선종양학과) ;
  • 권형철 (전북대학교 의과대학 방사선종양학과) ;
  • 김양수 (전북대학교 병원 방사선종양학과) ;
  • 이선영 (전북대학교 의과대학 방사선종양학과)
  • Kim, Seok Min (Department of Radiation Oncology, Chonbuk National University Hospital) ;
  • Gwak, Geun Tak (Department of Radiation Oncology, Chonbuk National University Hospital) ;
  • Lee, Seung Hun (Department of Radiation Oncology, Chonbuk National University Hospital) ;
  • Kim, Jung Soo (Department of Radiation Oncology, Institute for Medical Sciences, Chonbuk National University Medical School) ;
  • Kwon, Hyoung Cheol (Department of Radiation Oncology, Institute for Medical Sciences, Chonbuk National University Medical School) ;
  • Kim, Yang Su (Department of Radiation Oncology, Chonbuk National University Hospital) ;
  • Lee, Sun Young (Department of Radiation Oncology, Institute for Medical Sciences, Chonbuk National University Medical School)
  • 발행 : 2018.12.29

초록

목 적 : 폐의 우측후사방향 선량전달시, Carbon Side Rail과 환자 고정기구인 Vac-lok이 미치는 영향을 보고자 한다. 대상 및 방법 : Vac-lok의 오른쪽 부분을 10, 20, 30 mm 두께로 제작하였다. 측정은 유리선량계를 이용하여 측정하였고, 측정점은 팬텀 우측 폐의 center Point를 기준으로 좌, 우, 하, 상 방향 각각 A, B, C, D Point로 설정 하였다. 각 point에 유리선량계를 삽입한 후 couch의 Side Rail을 외측(Out)으로 뺀 후 vac-lok을 놓지 않은 no vac-lok, 그리고 10, 20, 30 mm의 vac-lok 위에 팬텀을 세팅하였다. 중심점에 6 MV 광자선을 조사야 $10{\times}10cm^2$, SAD 100 cm, 겐트리 각도 $225^{\circ}$로 하여 300 MU/min 선량률과 100 MU 조사선량을 전달하였다. 측정은 5회씩 실시하였고, 마찬가지로 Side Rail을 내측(In)으로 넣은 후 각 point에 대해서도 같은 조건으로 5 회씩 측정하여 평균값을 산출하였다. 결 과 : side rail에 따라서는 중심점, A, B, C, D Point 각각 -11.8 %, -12.3 %, -4.1 %, -12.3 %, -7.3 %의 선량 감소를 보였다. Side-Rail-Out에서 10 mm vac-lok의 경우 약 -0.9 %가 감소되었고, 20 mm vac-lok 사용 시 약 -2.0 %, 30 mm vac-lock 사용 시 약 -3.0 %가 감소되었다. Side-Rail-In에서 10 mm vac-lok의 경우 약 -1.0 %가 감소되었고, 20 mm vac-lok 사용 시 약 -2.1 %, 30 mm vac-lok 사용 시 약 -3.0 %가 감소되었다. Side-Rail-In 상태의 no vac-lok 선량 값을 기준으로 Side-Rail-Out 상태의 10, 20, 30 mm vac-lok을 사용할 때, side rail에 대한 선량 감소에 더하여 중심점에서는 약 -0.9 %, -1.8 % -2.4 %, A point에서는 -0.5 %, -1.6 %, -2.1 %, B point에서는 약 -0.9 %, -2.0 %, -3.2 %, C Point에서는 -1.0 %, -2.1 %, -3.1 %, D point에서는 약 -1.0 %, -1.6 %, -3.1 %의 추가적인 선량 감소를 나타냈다. 결 론 : 폐를 비롯한 우측후사방향 방사선 치료 시 side rail에 대해 주의를 기울이고, vac-lok 제작 시 vaclok 두께에 대해 관심을 갖는다면 더 나은 치료 효과를 기대해 볼 수 있으리라 사료된다.

Purpose : To evaluate the effect of carbon couch side rail and vacuum immobilization device in case of lung RPO irradiation. Materials and Methods : The 10, 20, 30 mm thickness of vac-lok's right side were obtained. To measure of doses, glass dosimeters were used and measured reference point is left lung center at the phantom. A, B, C, and D points are left, right, down, and up directions based on the center point. In the state of Side-Rail-Out, place the without vac-lok, with the thickness of 10, 20, and 30 mm vac-lok. After the glass dosimeters was inserted in center, A, B, C, and D points, 100 MU of 6 MV X-ray were irradiated to the referenced center point in the condition of $10{\times}10cm^2$ field size, SAD 100 cm, gantry angle 225, 300 MU/min dose rate. Five measurements were made for each point. In the state of Side-Rail-In, five measurement were made for each point under the same conditions. The average is measured on each of the five Side-Rail-Out and Side-Rail-In measurements. Results : In the presence of side rail, the dose reduction ratio was -11.8 %, -12.3 %, -4.1 %, -12.3 %, -7.3 % for each A, B, C, and D points. In the state of Side-Rail-Out, the dose reduction ratio for the using 10 mm thickness of vac-lok was -0.9 % than without vac-lok. The dose reduction ratio for the using 20 mm thickness of vac-lok was -2.0 %, for the using 30 mm thickness of the vac-lok was -3.0 % than without vac-lok. In the state of Side-Rail-In, the dose reduction ratio for the using 10 mm thickness of vac-lok was -1.0 % than without vac-lok. The dose reduction ratio for the using 20 mm vac-lok was -2.1 %, for the using 30 mm vac-lok was -3.0 % than without vac-lok. Based on the value of no vac-lok dose in the Side-Rail-In state, The dose reduction ratios for the using 10 mm, 20 mm and 30 mm thickness of vac-loks In the Side-Rail-Out that the center point were -12.7 %, -13.7 %, -14.2 % and -12.8 %, -13.8 %, -14.5 % respectively at point A. The dose reduction ratios for the same conditions to the B point were -4.9 %, -6.1 %, -7.1 % and -13.4 %, -14.4 %, -15.5 % respectively at point C. The dose reduction ratios for the same conditions to the D point were -8.4 %, -9.0 %, -10.4 % respectively. Conclusion : The attenuation was caused by presence of side rails and thickness of vac-lok. Pay attention to these attenuation factors, making it a more effective radiation therapy.

키워드

참고문헌

  1. Huh SJ, Park CI. Advances in radiation oncologyin new millennium in Korea, J Korean Soc Ther Radiol Oncol. 2000;1 8(3): 167-176
  2. Hanks GE, Schultheiss TE, Hunt MA, Epstein B. Factors influencing incidence of acute grade 2 morbidity in conforaml and standard radiation treatment of prostate cancer. Int J Radat Oncol Biol Phys. 1995;31(1): 25-29 https://doi.org/10.1016/0360-3016(94)00366-S
  3. Suh YL, Yi BY, Shin SA, Kim JH, Ahn SD, Lee SW, Choi EK. A feasibility study on the abdomen immobilization with air injected balloon blanket. Korean J Med Phys. 2002; 13(3): 176-180
  4. Pollack A, Zegars GK, Starkschall G, Childress CH, Kopplin S, Boyer AL, Rosen II. Conventional vs conformal radiotherapy for prostate cancer: preliminary results of dosimetry and acute toxicity. Int J Radat Oncol Biol Phys. 1996; 34(3): 555-564 https://doi.org/10.1016/0360-3016(95)02103-5
  5. Huh SN, Cho W, Park YK, Ha SW. Development of devices for improving the reproducibility of patient positioning on a breast board. J Korean Soc Ther Radiol Oncol. 2005;23(2):123-130
  6. Fukunaga-Johnson N, Sandler HM, McLaughlin PW, Strawderman MS, Grijalva KH, Kish KE, Lichter AS. Results of 3D conformal radiotherapy in the treatment of localized prostate cancer., Int J Radit Oncol Biol Phys. 1997; 38(2): 311-317 https://doi.org/10.1016/S0360-3016(97)82499-6
  7. CIVCO. Radiation Oncology 2010 Source book.2010:61-73
  8. Koi-Wei Lee. M.S., Jian-Kuen Wu. et al.: skin dose impact from vacuum immobilization device and carbon fiber in intensity modulated radiation therapy for prostate cancer. Medical Dosimetry 2008: 34: 228-232
  9. Olch A. J. et al.; Dosimetric effects caused by couch tops and immobilization devices report of AAPM Task Group 176. Med. Phys. 2014; 41: 061501 https://doi.org/10.1118/1.4876299
  10. Seppala J K, Kulmala J A. Increased beam attenuation and surface dose by different couch inserts of treatment tables used in megavoltage radiotherapy. J Appl Clin Med Phys 2011; 12 (4): 3554
  11. S. J. Meara and K. A. Langmack, "An investigation into the use of carbon fibre for megavoltage radiotherapy applications," Phys. Med. Biol. 1998; 43(5), 1359-1366 https://doi.org/10.1088/0031-9155/43/5/025
  12. S. McCormack, J. Diffey, and A. Morgan, "The effect of gantry angle on megavoltage photon beam attenuation by a carbon fiber couch insert," Med. Phys. 2005; 32: 483-487 https://doi.org/10.1118/1.1852792
  13. W. K. Myint, M. Niedbala, D. Wilkins, and L. H. Gerig, "Investigatingtreatment dose error due to beam attenuation by a carbon fiber tabletop," J. Appl. Clin. Med. Phys. 2006; 7(3): 21-27
  14. S. C. Vieira, R. S. Kaatee, M. L. Dirkx, and B. J. Heijmen, "Two dimensional measurement of photon beam attenuation by the treatmentcouch and immobilization devices using an electronic portal imaging device," Med. Phys. 2003; (30) 2981-2987
  15. Olch AJ and Lavey RS. Reproducibility and treatment planning advantages of a carbon fiber relocatable head fixation system. Radiother Oncol. 2002;65(3): 165-68 https://doi.org/10.1016/S0167-8140(02)00282-7
  16. Mihaylov I, et al. Modeling of carbon fiber attenuation properties with a commercial treatment planning system. Med Phys. 2008; 35: 4982-5 https://doi.org/10.1118/1.2982135
  17. Cheung T, Butson MJ, Yu Peter KN. Evaluation of build-up dose from 6 MV X-rays under pelvic and abdominalpatient immobilisation devices. Radiation Measurement 2002; 35(3): 235-8 https://doi.org/10.1016/S1350-4487(01)00285-2
  18. Snachez-Nietro B. Nahum AE. The Delta- TCP Concept: A clinically useful measure of tumour control probability Int J Radiat Oncol Biol Phys 1999; 44: 369-380 https://doi.org/10.1016/S0360-3016(99)00029-2
  19. 김창규.: 자체제작 Pb 밴딩을 이용한 피폭선량 감소, The Journal of Digital Policy & Management 2013; 11(6): 269-273
  20. 최재호, 강구준, 장서구.: DAP(Dose Area Product)를 이용한 TLD와 PLD의 선량 측정 비교. 한국콘텐츠학회논문지 2012; 12: 244-250