400 臨床技術 Code No 富永弘史 2 荒木不次男 1 川﨑啓一 1 岩下雄紀 3 下東吉信兼武 1 坂田潤一 1 渚 1 奥田智子冨山友希緒言 intensity modulated radiation ther

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1 400 臨床技術 Code No. 430 富永弘史 2 荒木不次男川﨑啓一岩下雄紀 3 下東吉信兼武坂田潤一渚奥田智子冨山友希緒言 intensity modulated radiation therapy: IMRT stereotactic body radiation therapy: SBRT, 2 3, 4 2 X X image guided radiation therapy: IGRT 5 6 IGRT X 7 9 ose Impact of a Carbon Fiber Couch for Stereotactic Body Radiation Therapy of Lung Tumors Hirofumi Tominaga, Fujio Araki, 2 Yoshinobu Shimohigashi, 3 Nagisa Kanetake, Yuki Tomiyama, 4 Keiichi Kawasaki, Yuki Iwashita, Junichi Sakata, and Tomoko Okuda Kumamoto Radiosurgery Clinic 2 Faculty of Life Sciences, Kumamoto University 3 epartment of Radiological Technology, Kumamoto University Hospital 4 Graduate School of Health Sciences, Kumamoto University Received July 25, 202; Revision accepted February 5, 203 Code No. 430 Summary The aim of this study was to measure the dose attenuation caused by a carbon fiber radiation therapy table (Imaging Couch Top; ICT, BrainLab) and to evaluate the dosimetric impact of ICT during stereotactic body radiation therapy (SBRT) in lung tumors. The dose attenuation of ICT was measured using an ionization chamber and modeled by means of a treatment planning system (TPS). SBRT was planned with and without ICT in a lung tumor phantom and ten cases of clinical lung tumors. The results were analyzed from isocenter doses and a dose-volume histogram (VH): 95, mean, V 20, V 5, homogeneity index (HI), and conformity index (CI). The dose attenuation of the ICT modeled with TPS agreed to within ±% of the actually measured values. The isocenter doses, 95 and mean with and without ICT showed differences of 4. 5% for posterior single field and three fields in the phantom study, and differences of % for five fields and rotation in the phantom study and six fields in ten clinical cases. The dose impact of ICT was not significant for five or more fields in SBRT. It is thus possible to reduce the dose effect of ICT by modifying the beam angle and beam weight in the treatment plan. Key words: carbon fiber couch, attenuation, stereotactic body radiation therapy (SBRT), couch modeling *Proceeding author

40 Fig. Imaging Couch Top (BrainLab): (a) and (b); (c) is a section. Fig. 2 Experimental setup for measurements. 9 6 0, 4~20, 2, 4, 8, 20, 2 Njeh 6 MV-X IMRT 3 IMRT.

2 40 Fig. Imaging Couch Top (BrainLab): (a) and (b); (c) is a section. Fig. 2 Experimental setup for measurements , 4~20, 2, 4, 8, 20, 2 Njeh 6 MV-X IMRT 3 IMRT.6 Vanetti 2 6 MV-X volumetric modulated arc therapy: VMAT planning target volume: PTV 2. 4 three dimensional conformal radiotherapy: 3-CRT monitor unit MU MV-X , 2 6, 9, 22, 23 radiation treatment planning system: RTPS computed tomography CT PTV organ at risk: OAR 2, 5, 23 PTV OAR dose-volume histogram: VH. 使用機器 Imaging Couch Top: ICT BrainLAB Fig. ICT 530 mm 50 mm 2 mm 46 mm ICT 2.5 mm multi-leaf collimator MLC Novalis Tx Varian Medical Systems cm 3 PTW Exradin A-4SL 0.06 cm 3 Standard Imaging RAMTEC Smart I mrt IBA osimetry RT-3000-New TPS Eclipse Ver.0.0 Varian Medical Systems Acuros XB Acuros XB Monte Carlo 24, mm 2. 方法 2- ICT Fig. 2 ICT I mrt 0.6 cm 3 ρ=.045 g/cm 3 Vol. 69 No. 4 Apr 203

3 402 ρ e=.02 source-axis distance SA 00 cm 6 MV 0 MV 5 5 cm cm 2 ICT θ= MU 3 with couch(θ) ICT θ= without couch(θ) ICT θ ose attenuation(θ) % ose attenuation( θ) = without couch ( θ) with couch( θ) 00(%) ( θ) without couch 2-2 ICT ICT I mrt 0.6 cm 3 CT TPS TPS ICT ICT TPS ICT TPS CT 2-3 Fig. 3 ABS ρ=.05 g/cm 3 SH-800; ρ= g/cm 3 TM; ρ=.00 g/cm cm 3 CT TPS gross tumor volume: GTV =PTV PTV 5 mm 6 MV Gy MU Acuros XB ABS TM Water SH-800 Lung Water SH-800 Lung TPS PTV 95 mean homogeneity index: HI 26 Fig. 3 Schematic illustration of a lung tumor phantom. conformity index: CI 27 V 20 V 5 VH HI HI = 2% 98% 50% % 98% 50% PTV HI CI Vpi CI = V 3 T Vpi VT target volume PTV CI Table CT CT CT internal target volume: ITV ITV set-up margin SM 5 0 mm PTV PTV 3 cm cm cm 3 X 6 MV 6 48 Gy/4 Fr MU PTV 95 mean HI CI V 20 V 5 VH

4 403 Table Patient characteristics Case number Tumor location GTV (cm 3 ) PTV (cm 3 ) right lung, upper lobe right lung, upper lobe right lung, lower lobe left lung, lower lobe right lung, middle lobe right lung, upper lobe left lung, upper lobe left lung, upper lobe right lung, upper lobe right lung, lower lobe Fig. 4 Percentage dose attenuation measured and calculated with ICT for (a) 5 5 cm and (b) 0 0 cm fields for 6 MV and 0 MV photons. a b 3. 結果 3- ICT TPS ICT TPS 6 MV 0 MV 5 5 cm cm 2 Fig. 4 a b ICT 25 6 MV 0 MV 5 5 cm cm cm cm ICT TPS CT 350 HU 920 HU CT Fig. 4 a b 6 MV 0 MV ± 3-2 Table 2 TPS 3 TPS TPS 2.6 Table 3 PTV 95 mean HI CI V 20 V mean HI CI V 20 V 5 Vol. 69 No. 4 Apr 203

5 404 Table 2 Comparison of absolute doses between measurements and TPS without couch and with couch in a lung tumor phantom for, 2, 3, and 5 fields and rotation Measured dose TPS without couch TPS with couch (Gy) ose (Gy) ifference (%) ose (Gy) ifference (%) field fields fields fields Rotation Table 3 Comparison of isocenter doses, 95, mean, HI, CI, V 20 and V 5 between without couch and with couch in a lung tumor phantom for, 2, 3, and 5 fields and rotation IC dose (%) 95 (%) mean (%) HI CI V 20 (%) V 5 (%) Wo W Wo W Wo W Wo W Wo W Wo W Wo W field fields fields fields Rotation IC dose: isocenter dose, HI: homogeneity index, CI: conformity index, Wo: without couch, W: with couch Table 4 Comparison of ten patients of isocenter doses, 95, mean, HI, CI, V 20 and V 5 between without couch and with couch Case IC dose (%) 95 (%) mean (%) HI CI V20 (%) V5 (%) Number Wo W Wo W Wo W Wo W Wo W Wo W Wo W Table mean HI CI V 20 V 5 Fig. 5 a b PTV 48 Gy.2 Gy.4 Fig. 6 3 PTV VH 95.4 mean.4 HI CI V 20 V 5 Table mean HI CI V 20 V 5 4. 考察 ICT Seppälä 0 Njeh 6 MV-X 0 0 cm

405 a b Fig. 5 ose distributions (a) without couch and (b) with couch in a clinical lung tumor (case 3) for six non-coplanar beams. Fig. 6 ose volume histograms for PTV and lung for with and without couch for a patient (case 3).

6 405 a b Fig. 5 ose distributions (a) without couch and (b) with couch in a clinical lung tumor (case 3) for six non-coplanar beams. Fig. 6 ose volume histograms for PTV and lung for with and without couch for a patient (case 3) ICT ibeam Evo Evo Elekta Oncology Systems Evo 4 Smith 6 6 MV-X cm Evo ICT Fig. ICT Evo 0.8 mm 4 Smith 6.2 ICT X Table 2 ICT ICT 350 HU 920 HU X ± 4 Evo 50 HU 000 HU Mihaylov g/cm 3 0. g/cm 3 TPS Njeh Vanetti IMRT VMAT VMAT TPS Vol. 69 No. 4 Apr 203

7 結論 ICT 25 6 MV 0 MV 5 5 cm cm TPS ICT ± 参考文献 Ikushima H, Balter P, Komaki R, et al. aily alignment results of in-room computed tomography-guided stereotactic body radiation therapy for lung cancer. Int J Radiat Oncol Biol Phys 20; 79(2): Li W, Purdie TG, Taremi M, et al. Effect of immobilization and performance status on intrafraction motion for stereotactic lung radiotherapy: analysis of 33 patients. Int J Radiat Oncol Biol Phys 20; 8(5): Hong TS, Tomé WA, Chappell RJ, et al. The impact of daily setup variations on head-and-neck intensity-modulated radiation therapy. Int J Radiat Oncol Biol Phys 2005; 6(3): Gutfeld O, Kretzler AE, Kashani R, et al. Influence of rotations on dose distributions in spinal stereotactic body radiotherapy (SBRT). Int J Radiat Oncol Biol Phys 2009; 73(5): IGRT awson LA, Sharpe MB. Image-guided radiotherapy: rationale, benefits, and limitations. Lancet Oncol 2006; 7(0): Meara SJ, Langmack KA. An investigation into the use of carbon fibre for megavoltage radiotherapy applications. Phys Med Biol 998; 43(5): Vieira SC, Kaatee RS, irkx ML, et al. Two-dimensional measurement of photon beam attenuation by the treatment couch and immobilization devices using an electronic portal imaging device. Med Phys 2003; 30(): Li H, Lee AK, Johnson JL, et al. Characterization of dose impact on IMRT and VMAT from couch attenuation for two Varian couches. J Appl Clin Med Phys 20; 2(3): Seppälä JK, Kulmala JA. Increased beam attenuation and surface dose by different couch inserts of treatment tables used in megavoltage radiotherapy. J Appl Clin Med Phys 20; 2(4): Njeh CF, Raines TW, Saunders MW. etermination of the photon beam attenuation by the BrainLAB imaging couch: angular and field size dependence. J Appl Clin Med Phys 2009; 0(3): Vanetti E, Nicolini G, Clivio A, et al. The impact of treatment couch modelling on RapidArc. Phys Med Biol 2009; 54(9): Hayashi N, Shibamoto Y, Obata Y, et al. Megavoltage photon beam attenuation by carbon fiber couch tops and its prediction using correction factors. J Radiat Res 200; 5(4): ; 67(2): Mihaylov IB, Corry P, Yan Y, et al. Modeling of carbon fiber couch attenuation properties with a commercial treatment planning system. Med Phys 2008; 35(): Smith W, Christophides, ean C, et al. osimetric characterization of the ibeam evo carbon fiber couch for radiotherapy. Med Phys 200; 37(7): Poppe B, Chofor N, Rühmann A, et al. The effect of a carbon-fiber couch on the depth-dose curves and transmission properties for megavoltage photon beams. Strahlenther Onkol 2007; 83(): Spezi E, Angelini AL, Romani F, et al. Evaluating the influence of the Siemens IGRT carbon fibre tabletop in head and neck IMRT. Radiother Oncol 2008; 89(): Gerig LH, Niedbala M, Nyiri BJ. ose perturbations by two carbon fiber treatment couches and the ability of a commercial treatment planning system to predict these effects. Med Phys 200; 37(): Mihaylov IB, Bzdusek K, Kaus M. Carbon fiber couch effects on skin dose for volumetric modulated arcs. Med Phys 20; 38(5): Gillis S, Bral S, e Wagter C, et al. Evaluation of the Sinmed Mastercouch as replacement for a standard couch. Radiother Oncol 2005; 75(2): McCormack S, iffey J, Morgan A. The effect of gantry angle on megavoltage photon beam attenuation by a carbon fiber couch insert. Med Phys 2005; 32(2): Teke T, Gill B, uzenli C, et al. A Monte Carlo model of the Varian IGRT couch top for RapidArc QA. Phys Med Biol 20; 56(24): Bush K, Gagne IM, Zavgorodni S, et al. osimetric validation of Acuros XB with Monte Carlo methods for photon dose calculations. Med Phys 20; 38(4): Han T, Mikell JK, Salehpour M, et al. osimetric comparison of Acuros XB deterministic radiation transport method with Monte Carlo and model-based convolution methods in heterogeneous media. Med Phys 20; 38(5): ICRU Report 83. Prescribing, recording and reporting photon-beam Intensity-Modulated Radiation Therapy (IMRT). Oxford, UK; 200: :

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06_学術_関節単純X線画像における_1c_梅木様.indd Arts and Sciences X The formulation of femoral heard measurement corrected enlargement ratio using hip joints X-ray Imaging 1 2 1 1 1 2 Key words: Bipolar Hip Arthroplasty (BHA) Preoperative planning Enlargement

400 臨床技術 Code No 富永弘史 2 荒木不次男 1 川﨑啓一 1 岩下雄紀 3 下東吉信 兼武 1 坂田潤一 1 渚 1 奥田智子 冨山友希 緒言 intensity modulated radiation ther

400 臨床技術 Code No 富永弘史 2 荒木不次男 1 川﨑啓一 1 岩下雄紀 3 下東吉信兼武 1 坂田潤一 1 渚 1 奥田智子冨山友希緒言 intensity modulated radiation ther