Point dose verification of Cranial Stereotactic Radiosurgery using micro Ionization Chamber and EBT3 film for 6MV FF and FFF beams in Varian TrueBeam® LINAC

• Autorzy: Mamballikalam Gopinath , Senthilkumar S. , Ahamed Basith P. M. , Inipully Rohit , Jayadevan P.M. , Clinto C.O. , Jaon Bos R. C.

Identyfikatory

DOI

10.2478/pjmpe-2020-0015

• Języki publikacji: EN

Abstrakty

EN

Introduction: Achieving high positional and dosimetric accuracy in small fields is very challenging due to the imbalance of charged particle equilibrium (CPE), occlusion of the primary radiation source, and overlapping penumbra regions. These factors make the choice of the detector for Stereotactic Radiosurgery (SRS) patient-specific quality assurance (PSQA) difficult. The aim of the study is to compare the suitability of EBT3 Gafchromic film against CC01 pinpoint chamber for the purpose of SRS and stereotactic Radiotherapy (SRT) dose verification. Material and Method: EBT3 Gafchromic film was calibrated against Treatment Planning System (TPS) doses (1 Gy – 35 Gy). CC01 pinpoint chamber and EBT3 film was used to verify Patient-Specific point doses of 21 intracranial lesions each planned with Static, Dynamic Conformal Arc (DCA), and Volumetric Arc Therapy (VMAT) using Varian TrueBeam Accelerator 6MV Flattening Filter (FF) and 6MV Flattening Filter Free (FFF) beams. The lesion sizes varied from 0.4 cc to 2.9 cc. The lesions were categorized into <1cc, 1cc-2cc and 2cc-3cc. Results: High variations in measured doses from TPS calculated dose were observed with small lesion volumes irrespective of the dosimeter. As the sizes decreased high uncertainty was observed in ion chamber results. CC01 was observed under-responding to film in small lesion sizes (<1cc), where nearly 50% of results under-responded in comparison with Film results. Film results were more or less consistent for static and DCA plans. Static and DCA plans were consistent passing more than 73% of the plans of the smallest lesion size category. VMAT showed very poor PSQA agreement for all three volumes (32.1% for <1cc, 14.3% for 2cc-3cc and 39.3% for 2cc-3cc). No significant difference was observed between 6MVFF and 6MVFFF beams from the chi-squared test. Conclusion: EBT3 Film was observed to be a more suitable detector for small lesion sizes less than 1cc, compared to CC01. As the volume increases, the response of CC01 and EBT3 film have no significant difference in performing PSQA for intracranial SRS/SRT. VMAT techniques for intra cranial SRS shows deviation from TPS planned dose for both EBT3 film and CC01 and should not be preferred choice of verification tools.

Słowa kluczowe

EN

patient specific quality assurance; stereotactic radiosurgery; EBT3 Gafchromic film; CC01 pinpoint chamber; flattening filter free photon beams

• Wydawca: Polskie Towarzystwo Fizyki Medycznej ; De Gruyter
• Czasopismo: Polish Journal of Medical Physics and Engineering
• Rocznik: 2020
• Tom: Vol. 26, Iss. 3
• Strony: 135--142
• Opis fizyczny: Bibliogr. 32 poz., rys., tab.

Twórcy

autor

Mamballikalam Gopinath

• R & D, Bharathiar University, Coimbatore, Tamilnadu, India & Aster Medcity, Kochi, Kerala, India

autor

Senthilkumar S.

• Rajaji Hospital & Madurai Medical College, Madurai, Tamilnadu, India

autor

Ahamed Basith P. M.

• Aster Medcity, Kochi, Kerala, India

autor

Inipully Rohit

• Aster Medcity, Kochi, Kerala, India

autor

Jayadevan P.M.

• Aster Medcity, Kochi, Kerala, India

autor

Clinto C.O.

• Aster Medcity, Kochi, Kerala, India

autor

Jaon Bos R. C.

• Aster Medcity, Kochi, Kerala, India

Bibliografia

• 1. Mamballikalam G, Senthilkumar S, Jaon Bos RC, et al. Stereotactic radiotherapy for small and very small tumours (≤1 to ≤3 cc): evaluation of the influence of volumetric-modulated arc therapy in comparison to dynamic conformal arc therapy and 3D conformal radiotherapy as a function of flattened and unflattened beam models. J Radiother Practice. 2020;1-7. doi: 10.1017/S146039691900102X
• 2. Devic S, McEwen MR, Orton CG. Radiochromic film is superior to ion chamber arrays for IMRT quality assurance. Med Phys. 2010;37(3):959-961. doi: 10.1118/1.3298377
• 3. Das IJ, Ding GX, Ahnesjö A. Small fields: Nonequilibrium radiation dosimetry. Med Phys. 2008:35(1): 206-215. doi:10.1118/1.2815356
• 4. Zhu TC, Bjarngard BE. The head-scatter factor for small field sizes. Med Phys. 1994;21(1):65–68. doi: 10.1118/1.597256
• 5. Li X, Soubra M, Szanto J, Gerig L. Lateral electron equilibrium and electron contamination in measurements of head-scatter factors using miniphantoms and brass caps. Med Phys. 1995;22(7):1167-1170. doi: 10.1118/1.597508
• 6. Sharpe M, Jaffray DA, Battista JJ, Munro P. Extrafocal radiation: A unified approach to the prediction of beam penumbra and output factors for megavoltage x-ray beams. Med Phys. 1995;22(12):2065-2074. doi: 10.1118/1.597648
• 7. Zhu T, Bjärngard B. The fraction of photons undergoing head scatter in X-ray beams. Phys Med Biol. 1995;40(6):1127-1134. doi: 10.1088/0031-9155/40/6/011
• 8. Zhu T, Bjärngard B, Shackford H. X‐ray source and the output factor. Med Phys. 1995;22(6):793-798. doi: 10.1118/1.597588
• 9. Attix FH. Introduction to radiological physics and radiation dosimetry. New York: Wiley; 1986.
• 10. Task Group-21, Radiation Therapy Committee, AAPM. A protocol for the determination of absorbed dose from high-energy photon and electron beams. Med Phys. 1983;10(6):741-771. doi:10.1118/1.595446
• 11. Sauer O, Wilbert J. Measurement of output factors for small photon beams. Med Phys. 2007;34(6):1983-1988. doi: 10.1118/1.2734383
• 12. Seuntjens J, Verhaegen F. Comments on `Ionization chamber dosimetry of small photon fields: a Monte Carlo study on stoppingpower ratios for radiosurgery and IMRT beams'. Phys Med Biol. 2003;48(21):L43-L455; author reply L46. doi: 10.1088/0031-9155/48/21/L01
• 13. ICRU 31. Average energy required to produce an ion pair. ICRU Report 31, International Commission on Radiation Units and Measurements, Washington, D.C; 1979.
• 14. Huber R, Combecher D, Burger G. Measurement of Average Energy Required to Produce an Ion Pair (W Value) for Low-Energy Ions in Several Gases. Radiat Res. 1985;101(2):237-251. doi: 10.2307/3576391
• 15. Verhaegen F, Das I, Palmans H. Monte Carlo dosimetry study of a 6 MV stereotactic radiosurgery unit. Phys Med Biol. 1998:43(10); 2755-2768. doi: 10.1088/0031-9155/43/10/006
• 16. Mack A, Scheib S, Major J, et al. Precision dosimetry for narrow photon beams used in radiosurgery - Determination of Gamma Knife (R) output factors. Med Phys. 2002;29(9): 2080-2089. doi: 10.1118/1.1501138
• 17. Wu A, Zwicker R, Kalend A, Zheng Z. Comments on dose measurements for a narrow beam in radiosurgery. Med Phys. 1193;20(3):777-779. doi: 10.1118/1.597032
• 18. Escudé L, Linero D, Molla M Miralbell R. Quality assurance for radiotherapy in prostate cancer: Point dose measurements in intensity modulated fields with large dose gradients. IntJ Radiat Oncol Phys. 2006;66(4):S136-S140. doi: 10.1016/j.ijrobp.2006.01.055
• 19. Koksal C, Akbas U, Kesen N, et al. Patient-specific quality assurance for intracranial cases in robotic radiosurgery system. J BUON. 2018;23(1):179-184.
• 20. McLaughlin W, Soares C, Sayeg J, et al. The use of a radiochromic detector for the determination of stereotactic radiosurgery dose characteristics. Med Phys. 1994;21(3):379-388.
• 21. GAFCHROMIC™ dosimetry media, type EBT-3. Available at: http://www.gafchromic.com/documents/EBT3_Specifications.pdf
• 22. Farahani M, Eichmiller F, McLaughlin W. Measurement of absorbed doses near metal and dental material interfaces irradiated by Xand gamma-ray therapy beams. Phys Med Biol. 1990;35(3):369-385. doi: 10.1088/0031-9155/35/3/006
• 23. Berger M. ESTAR, PSTAR, and ASTAR: Computer programs for calculating stopping-power and range tables for electrons, protons, and helium ions. 1992. NISTIR Report 4999.
• 24. Sayeg JA, Coffey CW, McLaughlin. The energy response of GafChromic radiation detectors. Med Phys. 1990:17;521.
• 25. Muench PJ, Meigooni AS, Nath R, McLaughlin WL. Photon energy dependence of the sensitivity of radiochromic film and comparison with silver halide film and LiF TLDs used for brachytherapy dosimetry. Med Phys. 1991;18(4):769-775. doi: 10.1118/1.596630
• 26. Niroomand-Rad A, Blackwell CL, Coursey BM, et al. Radiochromic Film Dosimetry: Recommendations of AAPM Radiation Therapy Committee Task Group 55. Med Phys. 1998;25(11):2093-2115. doi: 10.1118/1.598407
• 27. Battum LJ, HuizengaH, Verdaasdonk R, Heukelom S. How flatbed scanners upset accurate film dosimetry. Phys Med Biol. 2016;61(2):625-649. doi: 10.1088/0031-9155/61/2/625
• 28. Ning W, Lu S, Kim J, et al. Precise film dosimetry for stereotactic radiosurgery and stereotactic body radiotherapy quality assurance using Gafchromic™ EBT3 films. Radiat Oncol. 2016;4(11):132. doi: 10.1186/s13014-016-0709-4
• 29. Devic S, Tomic N, Soares G, Podgorsak E. Optimizing the Dynamic Range Extension of a Radiochromic Film Dosimetry System. Med Phys. 2009;36(2):429-437. doi: 10.1118/1.3049597.
• 30. Mamballikalam G, Senthilkumar S, Jayadevan PM, et al. Evaluation of dosimetric parameters of small fields of 6 MV flattening filter free photon beam measured using various detectors against Monte Carlo simulation. J Radiother Practice. 2020;1-8. doi: 10.1017/S1460396920000114
• 31. Pappas W, Maris T, Zacharopoulou T,. Small SRS photon field profile dosimetry performed using a PinPoint air ion chamber, a diamond detector, a novel silicon-diode array (DOSI), and polymer gel dosimetry. Analysis and intercomparison. Med Phys. 2008;35(10):4640-4648. doi: 10.1118/1.2977829
• 32. Popple R, Wu X, Kraus J, Thomas E, Brezovich I. SU-F-T-570: Comparison of Synthetic Diamond, Microionization Chamber, and Radiochromic Film for Absolute Dosimetry of VMAT Radiosurgery. Med Phys. 2016;43(6Part22):3594-3594. doi: 10.1118/1.4956755

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021).