Share This Article:

The Verification of iPlan Commissioning by Radiochromic EBT2 Films

DOI: 10.4236/ijmpcero.2012.11001    4,440 Downloads   12,298 Views   Citations

ABSTRACT

Purpose: To evaluate the measured dose distributions using radiochromic EBT2 films for small fields in iPlan (BrainLab) commissioning. Methods: Radiochromic EBT2 films were irradiated with 6 MV photons on a Varian Trilogy linac using polystyrene phantoms. The measurements included dose profiles and depth doses for field sizes of 1 × 1, 2 × 2, 3 × 3, 4 × 4, and 10 × 10 cm2 etc. The dose profile measurements were taken at the depth of 5 cm. The calibration films were irradiated at dmax(1.4 cm) for doses up to 6 Gy. Films were scanned using an Epson 10,000 XL flatbed scanner with 72 dpi resolution. Pixel values were converted to doses using the established calibration-curve. The 2D dose distributions were generated from the film data analysis. In-house software was utilized to compare the measured doses from films with the treatment planning data. In addition, selected patients’ SRS fields were also measured with the EBT2 films for comparison with iPlan. An EDGETM detector was also used to check the centralaxis doses for the SRS patients’ measurements. Results and Discussion: The measured planar dose distributions achieved more than 98% and 95% passing rates with a set of 2%/2 mm dose and DTA criteria for all square fields and all patient treatment fields (<5 × 5 cm2), respectively. Agreement with measurement data with the EDGETM detector at the central axis (±1%) was found with the plan data. This is the first report for SRS small photon-field measurement using the latest radiochromic film, EBT2. The results shown in this work indicate that the use of EBT2 film provides accurate dosimetry measure-ments for small photon beams. The measurements show excellent agreement with the iPlan TP commissioning data. Conclusions: The patient-specific EBT2 film QA for iPlan SRS patients showed good results. The EBT2 films could potentially be a useful dosimeter in verification of commissioning as well as patient-specific QA for SRS cases.

Conflicts of Interest

The authors declare no conflicts of interest.

Cite this paper

M. Chan, Q. Zhang, J. Li, P. Parhar, K. Schupak and C. Burman, "The Verification of iPlan Commissioning by Radiochromic EBT2 Films," International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, Vol. 1 No. 1, 2012, pp. 1-7. doi: 10.4236/ijmpcero.2012.11001.

References

[1] I. J. Das, G. X. Ding and A. Ahnesjo, “Small Fields: None-quilibrium Radiation Dosimetry,” Medical Physics, Vol. 35, No. 1, 2008, pp. 206-215. doi:10.1118/1.2815356
[2] A. E. Nahum, “Perturbation Effects in Dosimetry. i. Kilo-voltage X-Rays and Electrons,” Physics in Medicine and Biology, Vol. 41, No. 9, 1996, pp. 1531-1580. doi:10.1088/0031-9155/41/9/001
[3] M. B. Sharpe, D. A. Jaffray, J. J. Battista and P. Munro, “Extrafocal Raditation: A Unified Approach to the Prediction of Beam Penumbra and Output Factors for Mega-volrage X-Ray Beams,” Medical Physics, Vol. 22, No. 12, 1995, pp. 2066-2074. doi:10.1118/1.597648
[4] T. C. Zhu and B. E. Bjarngard, “The Head-Scatter Factor for Small Field Sizes,” Medical Physics, Vol. 21, No. 1, 1994, pp. 65-68. doi:10.1118/1.597256
[5] T. C. Zhu and B. E. Bjarngard, “The Fraction of Photons Undergoing Head Scatter in X-Ray Beams,” Physics in Medicine and Biology, Vol. 40, No. 6, 1995, pp. 1127-1134. doi:10.1088/0031-9155/40/6/011
[6] T. C. Zhu, B. E. Bjarngard and H. Shackford, “X-Ray Source and the Output Factor,” Medical Physics, Vol. 22, No. 6, 1995, pp. 793-798. doi:10.1118/1.597588
[7] P. Francescon, S. Cora, C. Cavedon, P. Scalchi, S. Rec-canello and F. Colombo, “Use of a New Type of Radiochromic Film, a New Parallel-Plate Micro-Chamber, Mos-fets, and TLD 800 Microcubes in the Dosimetry of Small Beams,” Medical Physics, Vol. 25, No. 4, 1998, pp. 503-511. doi:10.1118/1.598227
[8] O. A. Sauer and J. Wilbert, “Measurement of Output Factors for Small Photon Beams,” Medical Physics, Vol. 34, No. 6, 2007, pp. 1983-1988. doi:10.1118/1.2734383
[9] C. G. Soares, S. Trichter and S. Devic, “Radiochromic Film Dosimetry,” In: D. W. O. Rogers and J. Cygler, Eds., Clinical Dosimetry for Radiotherapy, Medical Physics Publishing, Madison, 2009.
[10] S. Chiu-Tsao, D. Medich and J. Munro, “The Use of New GAFCHROMIC? EBT Film for 125I Seed Dosimetry in Solid Water? Phantom,” Medical Physics, Vol. 35, No. 8, 2008, pp. 3787-3799. doi:10.1118/1.2955746
[11] M. Todorovic, M. Fischer, F. Cremers, E. Thom and Schmidt, “Evaluation of GafChromic EBT Prototype B for External Beam Dose Verification,” Medical Physics, Vol. 33, No. 5, 2006, pp. 1321-1328. doi:10.1118/1.2188077
[12] F. C. Su, Y. Liu, S. Stathakis, C. Shi, C. Esquivel and N. Papanikolaou, “Dosimetry Characteristics of GAFCHRO- MIC? EBT Film Responding to Therapeutic Electron Beams,” Applied Radiation and Isotopes, Vol. 65, No. 10, 2007, pp. 1187-1192. doi:10.1016/j.apradiso.2007.05.005
[13] S. Chiu-Tsao, Y. Ho, R. Shanka, L. Wang and L. B. Har-rison, “Energy Dependence of Response of New High Sensitivity Radiochromic Films for Megavoltage and Kilovoltage Radiation Energies,” Medical Physics, Vol. 32, No. 11, 2005, pp. 3350-3354. doi:10.1118/1.2065467
[14] M. J. Butson, T, Cheung and P. K. N. Yu, “Weak Energy Dependence of EBT Gafchromic Tm Film Dose Response in the 50 KVp-10 MVp X-Ray Range,” Applied Radiation and Isotopes, Vol. 64, No. 1, 2006, pp. 60-62. doi:10.1016/j.apradiso.2005.07.002
[15] J. G. H. Sutherland and D. W. O. Rogers, “Monte Carlo Calculated Absorbed-Dose Energy Dependence of EBT and EBT2 Film”, Medical Physics, Vol. 37, No. 3, 2010, pp. 1110-1116. doi:10.1118/1.3301574
[16] S. Devic, J. Seuntjens, W. Abdel-Rahman, M. Evans, M. Olivares, E. B. Podgorsak, T. Vuong and C. G. Soares, “Skin Dose Measurement Using Radiochromic Film in Clinical Applications,” Medical Physics, Vol. 33, No. 4, 2006, pp. 1116-1124. doi:10.1118/1.2179169
[17] M. J. Butson, T. Cheung and P. K. N. Yu, “Megavoltage X-Ray Skin Dose Variation with an Angle Using Grid Carbon Fibre Couch Tops,” Physics in Medicine and Biology, Vol. 52, No. 20, 2007, pp. 485-492.
[18] S. Price, M. Williams, M. Butson and P. Metcalfe, “Comparison of Skin Dose between Conventional Radiotherapy and IMRT,” Australasian Physical and Engineering Sciences in Medicine, Vol. 29, No. 3, 2006, pp. 272-277. doi:10.1007/BF03178577
[19] H. Chung, H. Jin, J. F. Dempsey, C. Liu, J. Palta, T.-S. Suh and S. Kim, “Evaluation of Surface and Build-Up Region Dose for Intensity-Modulated Radiation Therapy in Head and Neck Cancer,” Medical Physics, Vol. 32, No. 8, 2005, pp. 2682-2689. doi:10.1118/1.1992067
[20] S. Chiu-Tsao and M. F. Chan, “Evaluation of Two-Dimensional Bolus Effect of Immobilization/Support Devices on Skin Doses: A Radiochromic EBT Film Dosimetry Study in Phantom,” Medical Physics, Vol. 37, No. 7, 2010, pp. 3611-3626. doi:10.1118/1.3439586
[21] L. J. van Battum, D. Hoffmans, H. Piersma and S. Heu-kelom, “Accurate Dosimetry with GafchromicTM EBT Film of a 6 MV Photon Beam in Water: What Level Is Achievable?” Medical Physics, Vol. 35, No. 2, 2008, pp. 704-716. doi:10.1118/1.2828196
[22] C. Soares, “New Developments in Radiochromic Film Dosimetry,” Radiation Protection Dosimetry, Vol. 120,No. 1-4, 2006, pp. 100-106. doi:10.1093/rpd/nci698
[23] S. Devic, N. Tomic, C. G. Soares and E. B. Podgorsak, “Optimizing the Dynamic Range Extension of a Radio-chromic Film Dosimetry System,” Medical Physics, Vol. 36, No. 2, 2009, pp. 429-437. doi:10.1118/1.3049597
[24] F. Andic, Y. Ors, R. Davutoglu, S. B. Cifci, E. B. Ispir and M. E. Erturk, “Evaluation of skin Dose Associated with Different Frequencies of Bolus Applications in Post- Mastectomy Three-Dimensional Conformal Radiotherapy,” Journal of Experimental & Clinical Cancer Research, Vol. 28, 2009, p. 41. doi:10.1186/1756-9966-28-41
[25] J. E. Lye, D. J. Butler and D. V. Webb, “Enhanced Epidermal Dose Caused by Localized Electron Contamination from Lead Cutouts Used in Kilovoltage Radiother-apy,” Medical Physics, Vol. 37, No. 8, 2010, pp. 3935- 3939. doi:10.1118/1.3458722
[26] M. Oldham, H. Sakhalkar, P. Guo and J. Adamovics, “An Investigation of the Accuracy of an IMRT Dose Distribution Using Two- and Three-Dimensional Dosimetry Techniques,” Medical Physics, Vol. 35, No. 5, 2008, pp. 2072-2080. doi:10.1118/1.2899995
[27] D. Fontanarosa, L. C. Orlandini, I. Andriani and L. Bernardi, “Commissioning Varian Enhanced Dynamic Wedge in the Pinnacle Treatment Planning System Using Gaf-chromic? EBT Film,” Medical Physics, Vol. 36, No. 10, 2009, pp. 4504-4510. doi:10.1118/1.3223621
[28] J. Jr. Novotny, J. P. Bhatnagar, M. A. Quader, G. Bednarz, L. D. Lunsford and M. S. Huq, “Measurement of Relative Output Factors for the 8 and 4 mm Collimators of Leksell Gamma Knife Perfexion by Film Dosimetry,” Medical Physics, Vol. 36, No. 5, 2009, pp. 1768-1774. doi:10.1118/1.3113904
[29] M. Fragoso, N. Wen, S. Kumar, D. Liu, S. Ryu, B. Movsas, M. Ajlouni and I. J. Chetty, “ Dosimetric Veri-fication and Clinical Evaluation of a New Commercially Available Monte Carlo-Based Dose Algorithm for Application in Stereotactic Body Radiation Therapy (SBRT) Treatment Planning,” Physics in Medicine and Biology, Vol. 55, No. 16, 2010, pp. 4445-4464. doi:10.1088/0031-9155/55/16/S02
[30] O. A. Zeidan, S. A. L. Stephenson, S. L. Meeks, T. H. Wagner, T. R. Willoughby, P. A. Kupelian and K. M. Langen, “Characterization and Use of EBT Radiochromic Film for IMRT Dose Verification,” Medical Physics, Vol. 33, No. 6, 2006, pp. 4064-4072. doi:10.1118/1.2241047
[31] S. Chiu-Tsao and M. F. Chan, “Dose Response Characteristics of the New EBT-2 Film for Different Megavoltage Beams”, Medical Physics, Vol. 36, No. 6, 2009, p. 2604. doi:10.1118/1.3181842
[32] M. J. Butson, P. K. N. Yu, T. Cheung and H. Alnawaf, “Energy Response of the New EBT2 Radiochromic Film to X-Ray Radiation,” Radiation Measurements, Vol. 45, No. 7, 2010, pp. 836-839. doi:10.1016/j.radmeas.2010.02.016
[33] B. Arjomandy, R. Tailor, A. Anand, N. Sahoo, M. Gillin, K. Prado and M. Vicic, “Energy Dependence and Dose Response of Gafchromic EBT2 Film over a Wide Range of Photon, Electron, and Proton Beam Energies,” Medical Physics, Vol. 37, No. 5, 2010, pp. 1942-1947. doi:10.1118/1.3373523
[34] C. Andrés, A. del Castillo, R. Tortosa, D. Alonso and R. Barquero, “A Comprehensive Study of the Gafchromic EBT2 Radiochromic Film. A Comparison with EBT,” Medical Physics, Vol. 37, No. 12, 2010, pp. 6271-6278. doi:10.1118/1.3512792
[35] T. Kairn, J. Kenny, S. B. Crowe, A. L. Fielding, R. D. Franich, P. N. Johnston, R. T. Knight, C. M. Langton, D. Schlect and J. V. Trapp, “Technical Note: Modeling a Complex Micro-Multileaf Collimator Using the Standard BEAMnrc Distribution,” Medical Physics, Vol. 37, No. 4, 2010, pp. 1761-1767. doi:10.1118/1.3355873
[36] J. H. D. Wong, T. Knittel, S. Downes, M. L. F. Lerch, M. Petasecca, V. L. Perevertaylo, P. Metcalfe, M. Jackson and A. B. Rosenfeld, “The Use of a Silicon Strip Detector Dose Magnifying Glass in Stereotactic Radiotherapy QA and Dosimetry,” Medical Physics, Vol. 38, No. 3, 2011, pp. 1226-1238. doi:10.1118/1.3549759
[37] S. Chiu-Tsao and M. F. Chan, “Photon Beam Dosimetry in the Superficial Buildup Region Using Radiochromic EBT Film Stack,” Medical Physics, Vol. 36, No. 6, 2009, pp. 2074-2083. doi:10.1118/1.3125134
[38] P. K. N. Yu, M. J. Butson and T. Cheung, “Does Mechanical Pressure on Radiochromic Film Affect Optical Absorption and Dosimetry,” Australasian Physical and Engineering Sciences in Medicine, Vol. 29, No. 3, 2006, p. 29. doi:10.1007/BF03178580

  
comments powered by Disqus

Copyright © 2018 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.