Radiation Oncology Journal

The Korean Society for Radiation Oncology (대한방사선종양학회)
권호 표지

Development of Model Plans in Three Dimensional Conformal Radiotherapy for Brain Tumors

뇌종양 환자의 3차원 입체조형 치료를 위한 뇌내 주요 부위의 모델치료계획의 개발

  • Pyo Hongryull (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine) ;
  • Lee Sanghoon (Department of Radiation Oncology, National Health Insurance Medical Center) ;
  • Kim GwiEon (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine) ;
  • Keum Kichang (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine) ;
  • Chang Sekyung (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine) ;
  • Suh Chang-Ok (Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine)
  • 표홍렬 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 이상훈 (국민건강보험공단 일산병원 치료방사선과) ;
  • 김귀언 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 금기창 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 장세경 (연세대학교 의과대학 방사선종양학교실, 연세암센터) ;
  • 서창옥 (연세대학교 의과대학 방사선종양학교실, 연세암센터)
  • Published : 2002.03.01
Download PDF
⟨ Previous Next ⟩

Abstract

Purpose : Three dimensional conformal radiotherapy planning is being used widely for the treatment of patients with brain tumor. However, it takes much time to develop an optimal treatment plan, therefore, it is difficult to apply this technique to all patients. To increase the efficiency of this technique, we need to develop standard radiotherapy plant for each site of the brain. Therefore we developed several 3 dimensional conformal radiotherapy plans (3D plans) for tumors at each site of brain, compared them with each other, and with 2 dimensional radiotherapy plans. Finally model plans for each site of the brain were decide. Materials and Methods : Imaginary tumors, with sizes commonly observed in the clinic, were designed for each site of the brain and drawn on CT images. The planning target volumes (PTVs) were as follows; temporal $tumor-5.7\times8.2\times7.6\;cm$, suprasellar $tumor-3\times4\times4.1\;cm$, thalamic $tumor-3.1\times5.9\times3.7\;cm$, frontoparietal $tumor-5.5\times7\times5.5\;cm$, and occipitoparietal $tumor-5\times5.5\times5\;cm$. Plans using paralled opposed 2 portals and/or 3 portals including fronto-vertex and 2 lateral fields were developed manually as the conventional 2D plans, and 3D noncoplanar conformal plans were developed using beam's eye view and the automatic block drawing tool. Total tumor dose was 54 Gy for a suprasellar tumor, 59.4 Gy and 72 Gy for the other tumors. All dose plans (including 2D plans) were calculated using 3D plan software. Developed plans were compared with each other using dose-volume histograms (DVH), normal tissue complication probabilities (NTCP) and variable dose statistic values (minimum, maximum and mean dose, D5, V83, V85 and V95). Finally a best radiotherapy plan for each site of brain was selected. Results : 1) Temporal tumor; NTCPs and DVHs of the normal tissue of all 3D plans were superior to 2D plans and this trend was more definite when total dose was escalated to 72 Gy (NTCPs of normal brain 2D $plans:27\%,\;8\%\rightarrow\;3D\;plans:1\%,\;1\%$). Various dose statistic values did not show any consistent trend. A 3D plan using 3 noncoplanar portals was selected as a model radiotherapy plan. 2) Suprasellar tumor; NTCPs of all 3D plans and 2D plans did not show significant difference because the total dose of this tumor was only 54 Gy. DVHs of normal brain and brainstem were significantly different for different plans. D5, V85, V95 and mean values showed some consistent trend that was compatible with DVH. All 3D plans were superior to 2D plans even when 3 portals (fronto-vertex and 2 lateral fields) were used for 2D plans. A 3D plan using 7 portals was worse than plans using fewer portals. A 3D plan using 5 noncoplanar portals was selected as a model plan. 3) Thalamic tumor; NTCPs of all 3D plans were lower than the 2D plans when the total dose was elevated to 72 Gy. DVHs of normal tissues showed similar results. V83, V85, V95 showed some consistent differences between plans but not between 3D plans. 3D plans using 5 noncoplanar portals were selected as a model plan. 4) Parietal (fronto- and occipito-) tumors; all NTCPs of the normal brain in 3D plans were lower than in 2D plans. DVH also showed the same results. V83, V85, V95 showed consistent trends with NTCP and DVH. 3D plans using 5 portals for frontoparietal tumor and 6 portals for occipitoparietal tumor were selected as model plans. Conclusion : NTCP and DVH showed reasonable differences between plans and were through to be useful for comparing plans. All 3D plans were superior to 2D plans. Best 3D plans were selected for tumors in each site of brain using NTCP, DVH and finally by the planner's decision.

Keywords

References

  1. Rubin P, Carter SK. Combination radiation therapy and chemotherapy : A logical basis for their clinical use. CA-ACancer J for Clinicians 1976;26:274-292 https://doi.org/10.3322/canjclin.26.5.274
  2. Fletcher G. Clinical dose-response curves of human malignant epithelial tumors. Br J Radiol 1973;46:1 -12 https://doi.org/10.1259/0007-1285-46-541-1
  3. Perez CA, Bauer M, Edelstein S. Impact of tumor control on survival' in carcinoma of the lung treated with irradiation. Int J Radiat Oncol Biol Phys 1987;12:539-547
  4. Amstrong JG, Burman C, Leibel S. Three-dimensional conformal radiation therapy may improve the therapeutic ratio of high dose radiation therapy for lung cancer. lnt J RadiatOncol Biol Phys 1993;26:685-689 https://doi.org/10.1016/0360-3016(93)90289-8
  5. Boltefeld T, Burkelbach J, Boesecke R, Schegel W. Methods of image reconstruction from projections applied to conformation radiotherapy. Phys Med Biol 1990;35:1423-1434 https://doi.org/10.1088/0031-9155/35/10/007
  6. Boyer AL. Present and future developments in radiotherapytreatment units. Semin Radiat Oncol 1995;5:146-155 https://doi.org/10.1016/S1053-4296(95)80007-7
  7. Thornton Jr AF, Hegarty TJ, Haken RKT, et al. Threedimensional treatment planning of astrocytomas : A dosimetricstudy of cerebral irradiation. Int J Radiat Oncol Biol Phys 1991;20:1309-1315 https://doi.org/10.1016/0360-3016(91)90243-W
  8. Radany EH, Sandler HM, Haken RKT, et al. 3D conformal radiotherapy for malignant astrocytomas : dose escalation to 9OGy. Int J Radiat Oncol Biol Phys 1997;39(suppl):140
  9. Haken RKT, Frass BA, Lichter AS, Marsh LH, RadanyEH, Sandler HM. A brain tumor dose escalation protocolbased on effective dose equivalence to prior experience. Int J Radiat Oncol Biol Phys 1998;42:137-141
  10. Nakagawa K, Aoki Y, Fujimaki T, et al. High-dose conformal radiotherapy influenced the pattern of failure but didnot improve survival in glioblastoma multiforme. Int J RadiatOncol Bioi Phys 1998;40:1141-1149 https://doi.org/10.1016/S0360-3016(97)00911-5
  11. Burman C, Kucher GJ, Emami B, Goiten M. Fitting of normal tissue tolerance data to analytic function. Int J Radiat Oncol Biol Phys 1991;21:123-135
  12. Lyman JT, Wolbarst AB. Optimization of radiation therapyIII. A method of assessing complication probabilities fromdose- volume histograms. Int J Radiat Oncol Biol Phys 1987;13:103-109
  13. Kim HK, Thornton AF, Greenberg HS, Page MA, Junck L, Sandler HM. Results of re-irradiation of primary intracranial neoplasms with three-dimensional conformal therapy. Am J Clin Oncol (CCT) 1997;20:358-363 https://doi.org/10.1097/00000421-199708000-00007
  14. Pu AT, Sandler HM, Radany EH, et al. Low grade gliomas : preliminary analysis of failure patterns among patientstreated using 3D conformal external beam irradiation. Int J Radiat Oncol Biol Phys 1995;31:461-466 https://doi.org/10.1016/0360-3016(94)00400-F
  15. Sandler HM. 3D conformal radiotherapy for brain tumors. The University of Michigan experience. Front Radiat Ther Oncol Basel Karger 1996;29:250-254
  16. Niemierko A, Urie M, Goiten M. Optimization of 3D radiation therapy with both physical and biological end points and constraints. Int J Radiat Oncol Biol Phys 1992;23:99-108 https://doi.org/10.1016/0360-3016(92)90548-V
  17. Langer M, Morrill SS, Lane R. A test of the claim thatplan rankings are determined by relative complication and tumor-control probabilities. Int J Radiat Oncol Biol Phys 1998;41:451-457 https://doi.org/10.1016/S0360-3016(98)00057-1
  18. Sailer SL, Rosenman JG, Symon JR, Cullip TJ, ChaneyEL. The tetrad and hexad:maximum beam separation as astarting point for noncoplanar 3D treatment planning:prostatecancer as a test case. Int J Radiat Oncol Biol Phys 1994;30:439-446 https://doi.org/10.1016/0360-3016(94)90026-4
  19. Brahme A. Dosimetric precision requirements in radiationtherapy. Acta Radiol Oncol 1984;23:370-391
  20. Thawley SE, Panje WR, Batsakis JG, Lindberg RD. Comprehensive management of head and neck tumors. Philadelphia, W.B. Saunders Company. 1987:649-662
  21. Zaider M, Amols HI. A little to a lot or a lot to a little: Is NTCP always minimized in multiport therapy? lnt J Radiat Oncol Biol Phys 1998;41:945-950
  22. Soderstrom S, Brahme A. Which is the most suitablenumber of photon beam portals in coplanar radiation therapy? lnt J Radiat Oncol Biol Phys 1995;33:151-159 https://doi.org/10.1016/0360-3016(95)00113-D
  23. Mohan R, Ling CC. When becometh less more? lnt J Radiat Oncol Biol Phys 1995;33:235-237
  24. Soderstrom S, Brahme A. Optimization of the dose delivery in few field techniques using radio biological objective functions. Med Phys 1993;20:1201-1210 https://doi.org/10.1118/1.596971