Independent absolute dose calculation using the Monte Carlo method on CT-based data
Purpose: The accuracy of delivered dose is essential to the quality of radiotherapy treatment and tumor response. Generally, there are many types of dosimeter have been used to verify the dose from the treatment; however, most of these dosimeters are impractical for clinical situation. The goal of this study was to assess an absolute dose derived from the Monte Carlo (MC) method for the so-called 6- and 10-MV photon beams obtained from Varian Clinac 2100C linear accelerator.
Methods: The deposited doses have been calculated by the EGSnrc code system and, then, were converted into the absolute doses. We were also measured, in water phantom, by an ionization chamber and, in the chest region of Rando phantom, by a thermoluminescense dosimeter (TLD).
Results: The simulated data in water phantom agree with the results from both the measurement and previous studies within 2%. By comparing the absolute dose at various positions within the Rando phantom from two-opposing irradiated fields, the difference from MC calculation and TLD measurement was within 2%. Unfortunately, the calculated doses obtained from the collapse cone convolution (CCC) algorithm showed notable difference from that of the MC method. For the interface region within the provided field, it was higher than that from the MC method by almost 5% for the 6-MV and 7% for the 10-MV photon beam.
Conclusion: Our findings indicated that the MC method was on the level with the measurement for the dose determination, especially within the delivered field to a heterogeneous phantom.
Han T, Mikell JK, 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. 2011;38(5):2651-64.
Calvo OI, Gutierrez AN, Stathakis S, et al. On the quantification of the dosimetric accuracy of collapsed cone convolution superposition (CCCS) algorithm for small lung volume using IMRT. J Appl Clin Med Phys. 2012;13(3):43-59.
Wyatt M, Corredor C, Tamimi M, Miller LF. Comparison of treatment planning dose calculations with measurements and Monte Carlo calculations in a Rando phantom. Radiat Prot Dosimetry. 2005;116:461-5.
Popescu IA, Shaw CP, Zavgorodni SF, Beckham WA. Absolute dose calculations for Monte Carlo simulations of radiotherapy beams. Phys Med Biol. 2005;50(14):3375-92.
Francescon P, Cavedon C, Reccanello S, Cora S. Photon dose calculation of a three-dimensional treatment planning system compared to the Monte Carlo code BEAM. Med Phys. 2000;27(7):1579-87.
Liu HH, Verhaegen F, Dong L. A method of simulating dynamic multileaf collimators using Monte Carlo techniques for intensity-modulated radiation therapy. Phys Med Biol. 2001;46(9):2283-98.
Leal A, Sanchez-Doblado F, Arrans R, et al. Routine IMRT verification by means of an automated Monte Carlo simulation system. Int J Radiat Oncol Biol Phys. 2003; 56(1): 58-68.
Ma CM, Price Jr RA, Li JS, et al. Monitor unit calculation for Monte Carlo treatment planning. Phys Med Biol. 2004; 49(9): 1671-87.
International Atomic Energy Agency. Technical Report Series No.398: Absorbed dose determination in external beam radiotherapy. Vienna: IAEA, 2000.
Mobit PN, Nahum AE, Mayles P. A Monte Carlo study of the quality dependence factors of common TLD materials in photon and electron beams. Phys Med Biol. 1998;43(8):2015-32.
Kawakow I, Mainegra-Hing E, Rogers DWO. EGSnrcMP: the multi-platform environment for EGSnrc. NRCC report PIRS-877. Ottawa: National Research Council of Canada, 2006.
Rogers DWO, Karakow I, Seuntijens JP, et al. NRC user Codes for EGSnrc. NRCC report PIRS-702. Ottawa: National Research Council of Canada, 2010.
Roger DWO, Feddegon BA, Ding GX, et al. BEAM: A Monte Carlo code to stimulate radiotherapy units. Med Phys. 1995;22(5):503-24.
Roger DWO, Walters B, Kawrakow I. BEAMnrc User’s Manual. NRCC report PIRS 0509(A). Ottawa: National Research Council of Canada, 2006.
Walters B, Kawrakow I, Rogers DWO. DOSXYZnrc User’s Manual. NRCC report PIRS 794. Ottawa: National Research Council of Canada, 2006.
Ahnesjo A. Collapsed cone convolution of radiant energy for photon dose calculation in heterogeneous media. Med Phys. 1989;16(4):577-92.
Liu HH, Mackie TR, McCullough EC. Calculating output factors for photon beam radiotherapy using a convolution/superposition method based on a dual source photon beam model. Med Phys. 1997;24(12): 1975-85.
Ding GX. Using Monte Carlo simulations to commission photon beam output factors-a feasibility study. Phys Med Biol. 2003;48(23):3865-74.
Woo MK, Cunningham JR. The validation of the density scaling method in primary electron transport for photon and electron beams. Med Phys. 1990;17(2):187-94.
Fogliata A, Vanetti E, Albers D, et al. On the dosimetric behavior of photon dose calculation algorithms in the presence of simple geometric heterogeneities: comparison with Monte Carlo calculations. Phys Med Biol. 2007;52(5):1363-85.
James CL, Chow RJ, Michael KKL. Dosimetry of oblique tangential photon beams calculated by superposition /convolution algorithm: a Monte Carlo evaluation. J Appl Clin Med Phys. 2010;12(1):108-21.
This work is licensed under a Creative Commons Attribution 3.0 License.
International Journal of Cancer Therapy and Oncology (ISSN 2330-4049)
© International Journal of Cancer Therapy and Oncology (IJCTO)
To make sure that you can receive messages from us, please add the 'ijcto.org' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.