Dosimetric Comparison: Acuros XB vs AAA

Transcription

1 Dosimetric Comparison: Acuros XB vs AAA Leo El Hage, Chris James, Jim Frantzis, Roger Li, Venkata Sheshadri Epworth Radiation Oncology Epworth HealthCare Excellence. Everywhere. Everyday

2 Background Epworth Radiation Oncology Eclipse Treatment Planning System (TPS) v10 - Anisotropic Analytical Algorithm (AAA) - ACUROS XB - Pencil Beam Algorithm Epworth Radiation Oncology was one of the first sites in Australia to commission Acuros Currently: AAA for calculations using Megavoltage (MV) photons 2

3 Background Acuros : Accurate and Fast Boltzmann Transport Equation (BTE) In-house evaluation was required Literature search Clinical impact Positives and negatives 3

4 Background Eclipse Acuros XB Reported to improve dose calculation accuracy (Fogliata et al,2011) Matched only by Monte Carlo (Han et al, 2011) Better dose prediction than AAA Low density lung Fat Bone Air (Bush et al, 2011) Bush et al

5 Algorithm Comparison Monte Carlo Gold Standard, but slow..? Structure Monte Carlo Acuros AAA Lung = x Bone = X Fat = X Air = X Acuros: equivalent to 0.5 % AAA : 3.5% to 6.4% ( Han et al, 2011) 5

6 Method AAA vs ACUROS CIRS Thorax Phantom Point Dose measurements Ethics approval from Epworth H.R.E.C. Clinical Data sets Time Study 6

7 Method : CIRS Phantom 7

8 Method Plan Comparisons Clinical datasets 5 plans selected in 4 different sites: Pelvis Breast Thorax - Head & Neck Calculation algorithm changed to Acuros and re-calculated (total 40 plans) Same Monitor Units and 2.5mm Grid size Plans compared via DVH analysis Conformity Index Calculation time comparison 8

9 Method Calculation Of Conformity Index (CI) The CI was measured using the following formula 2 V 3D V4 D CI V 3D V4 V 3D = total volume of the PTV V 4D = total volume of 95% isodose line and is V3 D V4 D = the volume of their intersection CI Closer to 0 CI Closer to 1.0 Van t Riet, et al

10 Results Phantom Point Dose Measurements 10

11 Results Phantom Point Dose Measurements

12 Results Calculation Times 12

13 Results Breast Plan Comparison Plan AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS Mean Dose Gy Gy Gy 50.30Gy Gy Gy Gy Gy Gy Gy D 95 % Gy Gy Gy 46.72Gy Gy Gy Gy Gy Gy Gy D 98 % Gy Gy Gy Gy Gy 47.06Gy Gy Gy Gy Gy D 2% Gy Gy Gy 53.14Gy 52.22G y Gy Gy Gy Gy Gy CI

14 Results Breast Plan Comparison Plan AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS Mean Dose Gy Gy Gy Gy Gy D 95 % Gy Gy Gy Gy Gy D 98 % Gy Gy Gy Gy Gy D 2% Gy Gy 52.22G y Gy Gy CI

15 Results Pelvis Plan Comparison Plan AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS Mean Dose Gy Gy Gy Gy Gy D 95 % Gy Gy Gy Gy Gy D 98 % Gy Gy Gy Gy Gy D 2% Gy Gy Gy Gy Gy CI

16 Results Thorax Plan Comparison Plan AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS Mean Dose Gy Gy Gy Gy Gy D 95 % Gy Gy Gy Gy Gy D 98 % Gy Gy Gy Gy Gy D 2% Gy Gy Gy Gy 51.0 Gy CI

17 Results Head & Neck Plan Comparison Plan AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS AAA ACUROS Mean Dose 58.47Gy 52.90Gy 51.51gy 68.74Gy 59.46Gy D 95 % 52.95Gy 48.66Gy 39.65Gy 65.51Gy 53.91Gy D 98 % 47.10Gy 46.50Gy 29.38Gy 64.36Gy 50.46Gy D 2% 62.93Gy 55.17Gy 55.17Gy 71.77Gy 61.99Gy CI

18 Discussion Isodose Evaluation AAA ACUROS 18

19 Discussion: Pelvis 95% - AAA 95% - ACUROS 19

20 Discussion: Thorax 3DCRT 95% - AAA 95% - ACUROS 20

21 Discussion: Head & Neck 21

22 Conclusion Phantom study Acuros = measured Acuros is a better predictor of dose than AAA Can over or under estimate dose to PTV and conformity of 95% isodose More dose phantom measurements required for Acuros Not ready to implement 22

23 ACKNOWLEDGMENTS Special Mention to: Jim Frantzis Andrew Do Louis Huynh Yolanda Aarons Yen Tran Hannah Bignell Priya Gautam All the ERO team for their commitment to their professionalism and support 23

24 REFERENCES Bueno, M., Duch, M.A., Jurado Bruggeman, D., Agramunt Chaler, S., Munoz C., Dosimetric Verification of Acuros XB in Heterogeneities Against Experimental Measurements and monte Carlo Methods, ESTRO 31 Bush, K., Ansbacher, W., Wang, L., Mok, E., Xing, L., Fast and Accurate Solution of the Boltzmann Radiation Transport Equation for RT: Implementation and Validation., Stanford University, Radiation Oncology, Stanford CA, USABritish Columbia Cancer Agency - Vancouver Island Centre, Medical Physics, Victoria BC, Canada Bush, K., Gagne, I.M., Zavorodni, S., Ansbacher, W., Beckham, W., Dosimetric validation of Acuros XB with Monte Carlo methods for photon dose calculations, Department of Medical Physics, British Columbia Cancer Agency Vancouver Island Center, Victoria,British Columbia V8R 6V5, Canada, 2011 Failla, G et al. Acuros XB advanced dose calculation for Eclipse planning system, Varian Medical Systems, Clinical Perspectives, Acuros XB. Fogliata A., Nicolini, G., Clivio, A., Vanetti, E., Cozzi, L., Advanced Lung Treatment Using Different Modalities: Comparison of Acuros XB and AAA Dose Calculations, Oncology Institute of Southern Switzerland, Medical Physics, Bellinzona, Switzerland. Fogliata A., Nicolini, G., Clivio, A., Vanetti, E., Cozzi, L., Critical Appraisal of Acuros XB and Anisotropic Analytic Algorithm Dose Calculation in Advanced Non-Small-Cell Lung Cancer Treatments. Medical Physics Unit, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland, 2011 Fogliata A., Nicolini, G., Clivio, A., Vanetti, E., Mancosu, P., Cozzi, L., Dosimetric evaluation of Acuros XB Advanced Dose Calculation algorithm in heterogeneous media, Radiation Oncology, Vol 6, pp. 82, 2011 Fogliata A., Nicolini, G., Clivio, A., Vanetti, E., Mancosu, P., Cozzi, L., Dosimetric validation of the Acuros XB Advanced Dose Calculation algorithm:fundamental characterization in water., Phys. Med. Biol., Issue 56, pp ,

25 REFERENCES (2) Fogliata A., Nicolini, G., Clivio, A., Vanetti, E., Mancosu, P., Cozzi, L., Dosimetric validation of the Acuros XB Advanced Dose Calculation algorithm:fundamental characterization in water., Phys. Med. Biol., Issue 56, pp , 2011 Fogliata, A., et al. On the dosimetric impact of inhomogeneity management in the Acuros XB algorithm for breast treatment, Radiation Oncology 2011, Issue 6, pp. 103 Han et al., Dosimetric evaluation of AXB in heterogeneities. Med. Phys., Vol 38, Issue 5, 2011 Int J Radiat Oncol Biol Phys, Vol 37, pp , 1997 Kan, Leung, and Yu: Impact of Acuros XB on IMSRT for NPC, Med. Phys., Vol 39, Issue 8, 2012 Knöös, T., Kristensen, I., Per Nillson, Volumetric and Dosimetric Evaluation of Radiation Treatment Plans: Radiation Conformity Index, Division of Radiation Therapy Physics, Department of Radiation Physics, Lund University Hospital, Lund, Sweden, Int. J. Radiation Oncology Biol. Phys., Vol. 42, No. 5, pp , 1998 Sakthi, N., Keall, P., Mihaylov, I., Wu, Q., Wu, Y., Willamson, J., Schmidt-Ullrich, R., Siebers, J., Monte Carlo-Based Dosimetry of Head and Neck Patients Treated with SIB-IMRT, Department of Radiation Oncology, Virginia Commonwealth University, Richmond,VA. Int. J. Radiation Oncology Biol. Phys., Vol. 64,Issue 3, pp , 2006 Tao H., Mikell, J.K., Salehpour, M., Mourtada, F., Dosimetric comparison of Acuros XB deterministic radiation transport method with Monte Carlo and model-based convolution methods in heterogeneous media.med. Phys., Vol 38, Issue 5, 2011 Van t Riet, A, Mak, AC, Moerland, MA, et al. A conformation number to quantify the degree of conformality in brachytherapy and external beam irradiation: Application to the prostate. 25