The Journal of Korean Society for Radiation Therapy (대한방사선치료학회지)

Korean Society for Radiation Therapy (대한방사선치료학회)
권호 표지

A comprehensive comparison of IMRT and VMAT plan quality for orbital lymphoma

안와 림프종 환자의 방사선치료를 위한 세기조절방사선치료와 용적세기조절회전치료의 전산화 치료계획에 대한 고찰

  • Yoo, Soon Mi (Department of Radiation Oncology, Asan medical center, Department of Radiology, Dongnam Health University) ;
  • Ban, Tae Joon (Department of Radiation Oncology, Asan medical center, Department of Radiology, Dongnam Health University) ;
  • Yun, In Ha (Department of Radiation Oncology, Asan medical center, Department of Radiology, Dongnam Health University) ;
  • Baek, Geum Mun (Department of Radiation Oncology, Asan medical center, Department of Radiology, Dongnam Health University) ;
  • Kwon, Kyung Tae (Department of Radiation Oncology, Asan medical center, Department of Radiology, Dongnam Health University)
  • 유순미 (서울아산병원 방사선종양학과, 동남보건대학 방사선과) ;
  • 반태준 (서울아산병원 방사선종양학과, 동남보건대학 방사선과) ;
  • 유인하 (서울아산병원 방사선종양학과, 동남보건대학 방사선과) ;
  • 백금문 (서울아산병원 방사선종양학과, 동남보건대학 방사선과) ;
  • 권경태 (서울아산병원 방사선종양학과, 동남보건대학 방사선과)
  • Received : 2014.11.14
  • Accepted : 2014.12.02
  • Published : 2014.12.30
Download PDF
⟨ Previous Next ⟩

Abstract

Purpose : The purpose of this study is to compare the plan quality of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for the treatment of orbital lymphoma. IMRT, partial single arc(SA) and partial-double arc(DA) VMAT plans for four patients with orbital lymphoma treated at our institution were used for this study. Conformity Index(CI), Paddick's Conformity Index(PCI) and Homogeneity Index(HI) of planning target volume(PTV) were used to evaluate dosimetric quality of each plan. The Monitor Unit (MU), treatment time and dose of ipsilateral lens from each type of plan were measured for comparison. Materials and Methods : The CI of PTV for IMRT, SA and DA were measured as 0.88, 0.86, 0.92. The PCI of DA was the lowest as 1.33. Also HI of DA was the lowest in measured plans as 1.15. Mean dose of lens, lacrimal gland, optic chiasm, the opposite optic nerve and both orbit was analyzed with V30, V20, V10, V5. The result showed that the lowest dose in IMRT highest in SA in opposite lens, lacrimal gland, optic nerve, orbit. Results : Treatment time and average MU of IMRT was about three times higher than SA. Conclusion : Considering the superior plan quality as well as the delivery efficiency of VMAT compared with that of IMRT, VMAT may be the preferred modality for treating orbital lymphoma.

목 적 : 안와 림프종(orbital lymphoma) 방사선치료를 IMRT(intensity-modulated radiotherapy)와 VMAT (volumetric modulated arc therapy)을 이용한 RapidArc로 비교 분석해 보고자 한다. 대상 및 방법 : 본원에서 치료받은 안와 림프종 환자 4명을 대상으로 IMRT, VMAT을 이용한 partial-single arc(SA)와 partial-double arc(DA)로 전산화치료계획을 수립하였다. 각 치료계획의 평가는 PTV의 CI(conform -ity Index)값과 PCI(Paddick's Conformity Index)값, HI(Homogeneity Index)값을 구하여 비교 평가하였으며 주변 정상조직의 선량평가를 시행하였다. 또한 각 치료계획의 MU(Monitor Unit)값을 비교하고 치료시간과 수정체의 선량을 측정해보았다. 결 과 : PTV의 CI값을 분석한 결과 각 0.88, 0.86, 0.92로 DA의 값이 가장 컸으며 PCI값은 1.41, 1.44, 1.33으로 DA에서 값이 가장 작게 나타났다. 또한 HI값은 1.18, 1.20, 1.15로 DA에서 가장 낮은 것을 확인할 수 있었다. 안와 림프종 주변 정상조직의 mean dose와 $V_30$, $V_20$, $V_10$, $V_5$의 값을 분석하였다. 그 결과 반대측 수정체, 눈물샘, 시신경, 안와의 선량이 SA에서 가장 높았고 IMRT에서 가장 낮게 나타났다. 평균 MU값과 치료시간은 IMRT가 SA에 비해 약 3배 정도 높게 나타났다. 결 론 : 안와 림프종 환자 IMRT 치료는 장애를 최소화하고 종양 내 선량 균등성을 높이기 위한 일반적인 치료법이다. 하지만 최근 시행하고 있는 RapidArc 치료계획에서 종양 내 선량 균등성이 IMRT 치료계획보다 우수한 결과 값을 보였고 정상조직의 선량 비교에서 큰 차이를 보이지 않았을 뿐만 아니라 MU와 치료시간 또한 약 1/3로 줄일 수 있었다. 이러한 이점은 안와 림프종 환자의 RapidArc 치료계획에 대한 지속적인 연구를 통해 치료의 효율성을 높일 수 있을 것으로 사료된다.

Keywords

References

  1. Fitzpatrick PJ, Macko S. Lymphoreticular tumors of theorbit. Int J Radiat Oncol Biol Phys 1984;10:333-40. https://doi.org/10.1016/0360-3016(84)90051-8
  2. Bolek TW, Moyses HM, Marcus RB Jr, Gorden L 3rd, Maiese RL, Almasri NM, et al. Radiotherapy in the management of orbital lymphoma. Int J Radiat Oncol Biol Phys 1999;44:31-6. https://doi.org/10.1016/S0360-3016(98)00535-5
  3. Chao CK, Lin HS, Devineni VR, Smith M. Radiation therapy for primary orbital lymphoma. Int J Radiat Oncol Biol Phys 1995;31:929-34. https://doi.org/10.1016/0360-3016(94)00416-1
  4. Bhatia S, Paulino AC, Buatti JM, Mayr NA, Wen BC. Curative radiotherapy for primary orbital lymphoma. Int J Radiat Oncol Biol Phys 2002;54:818-23. https://doi.org/10.1016/S0360-3016(02)02966-8
  5. Zhou P, Ng AK, Silver B, Li S, Hua L, Mauch PM. Radiation therapy for orbital lymphoma. Int J Radiat Oncol Biol Phys 2005;63:866-71. https://doi.org/10.1016/j.ijrobp.2005.03.005
  6. Sharad Goyal, Alan Cohler, Jayne Camporeale, Venkat Narra, Ning J. Yue. Intensity-modulated radiation therapy for orbital lymphoma. Radiat Med(2008) 26:573-581 https://doi.org/10.1007/s11604-008-0276-1
  7. Wang, J.Z.; Li, X.A.; D''Souza, W.D. et al. Impact of prolonged fraction delivery times on tumor control probability: A note of caution for IMRT. Int. J. Radiat. Oncol. Biol. Phys. 57:543-52; 2003 https://doi.org/10.1016/S0360-3016(03)00499-1
  8. Hall, E. Intensity-modulated radiation therapy, pron, and the risk of second cancers. Int. J. Radiat. Oncol. Biol. Phys. 65:1-7; 2006 https://doi.org/10.1016/j.ijrobp.2006.01.027
  9. Yong Yin, Changsheng Ma, Min Gao, Jinhu Chen, Yidong Ma, Tonghai Liu, JIE Lu, Jinming Yu. Dosimetric comparison of rapidArc with Fixed gantry intensity-modulated radiotherapy treatment for multiple liver metastases radiotherapy. Medical Dosimetry, Vol. 36, No. 4, pp. 448-454, 2011 https://doi.org/10.1016/j.meddos.2010.12.001
  10. Bragg, C.; Windate, K.; Conway, J. Clinical implications of the anisotropic analytical algorithm for IMRT treatment planning and verification. Radiother. Oncol. 86:276-84; 2008 https://doi.org/10.1016/j.radonc.2008.01.011
  11. Fogliata, A.; Vanetti, E.; Albers, D.; et al. On the dosimetric behaviour of photon dose calculation algorithms in the presence of simple geometric heterogeneities: Comparison with Monte Carlo calculations. Phys. Med. Biol. 52:1363-85; 2007 https://doi.org/10.1088/0031-9155/52/5/011
  12. Knoos, T.; Wieslander, E.; Cozzi, L.; et al. Comparison of dose calculation algorithms for treatment planning in external photon beam therapy for clinical situations. Phys. Med. Biol. 51:5785-07; 2006 https://doi.org/10.1088/0031-9155/51/22/005
  13. Ulmer, W.; Pyyry, J.; Kaissl, W.A. 3D photon superposition/convolution algorithm and its foundation on results of Monte Carlo calculations. Phys. Med. Biol. 50:1767-0; 2005 https://doi.org/10.1088/0031-9155/50/8/010
  14. Otto, K. Volumetric modulated arc therapy: IMRT in a single arc. Med. Phys. 35:310-7; 2008 https://doi.org/10.1118/1.2818738