Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-24T14:12:15.440Z Has data issue: false hasContentIssue false
  • English
  • Français

Transmission portal in vivo dosimetry by means of the Monte Carlo method and the mathematical programminglanguage MATLAB

Published online by Cambridge University Press:  06 June 2014

K. Badraoui Čuprová
Get access

Abstract

Modern radiotherapy has increased demand for dose delivery verification. In this paper transmission portal dosimetry was considered. Portal detectors are a promising tool for 2D dosimetric verification and they are nowadays one of the most widely investigated topics. In this study an Electronic Portal Imaging Device (EPID) was positioned below the patient and the transmission images were captured during the irradiation. The principle of this verification consists of comparison of the acquired images with images predicted on the basis of the entrance fluence map and the tissue distribution in the patient. Such verification is not performed at any radiotherapy department in the Czech Republic. There is no system available for the prediction of transmission portal images. Even worldwide, there is still a lack of commercially available solutions. The aim of this paper is to present a new method of prediction of transmission portal images by means of the Monte Carlo (MC) method and the mathematical programming language MATLAB. The MC code EGSnrc (Electron Gamma Shower) was used. The validity of the presented method was verified by comparison of the predicted images with the acquired ones. The acquisition of EPID images was performed at the Hospital Na Bulovce. Three different validation tests were performed. In the first case, the EPID was irradiated by regular and irregular fields while there was nothing present in the beam path. In the second case, a water-equivalent phantom was added to the EPID and was irradiated by a number of irregular fields. In the third case, a real patient was present in the beam path and the EPID images were acquired during the patient’s treatment. The patient was irradiated by 8 treatment fields and the portal images were acquired during 5 treatment fractions. All of the acquired images were compared with the MC predicted ones by gamma analysis with gamma criteria of 3%, 3 mm. The average gamma values were 0.31−0.4, 0.34−0.4 and 0.35−0.61 in the first, second and third case, respectively. The results validate the developed method and demonstrate that MC is an effective tool for portal dose image prediction. MC may be favourably used for in vivo transmission dosimetry.

Keywords

patientdosimetryscintillation detectorMonte CarloMatlab
Type
Research Article
Information
Radioprotection , Volume 49 , Issue 3 , July 2014 , pp. 205 - 211
Copyright
© EDP Sciences, 2014

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Chin P.W. (2008) Monte Carlo portal dosimetry, Ph.D. thesis, University of Wales.
Chin, P.W., Spezi, E., Lewis, D.G. (2003) Monte Carlo simulation of portal dosimetry on a rectilinear voxel geometry: a variable gantry angle solution, Phys. Med. Biol. 48, N231-N238. Google ScholarPubMed
Chin, P.W., Lewis, D.G., Giddy, J.P. (2005) A Monte Carlo solution for external beam photon radiotherapy verification. In: American Nuclear Society Topical Meeting in MC, April 17–21, 2005, Chattanooga, Tennessee. Google Scholar
Chow J.C.L., Leung M.K.K. (2006) DOSCTP Users Manual, Princess Margaret Hospital, University Health Network, Toronto, Canada.
Chow, J.C.L., Leung, M.K.K. (2008) A graphical user interface for calculation of 3D dose distribution using Monte Carlo simulations, J. Phys.: Conf. Ser. 102, 012003. Google Scholar
Cufflin, R., Lewis, D.G., Millin, T. (2007) Monte Carlo portal dosimetry for IMRT verification. In: Monte Carlo Workshop and MCNEG 2007, March 26–27, 2007, NPL, UK. Google Scholar
Cufflin, R.S., Spezi, E., Millin, A.E., Lewis, D.G. (2010) An investigation of the accuracy of Monte Carlo portal dosimetry for verification of IMRT with extended fields, Phys. Med. Biol. 55, 4589-4600. Google ScholarPubMed
Engstrom, P.E., Haraldsson, P., Landberg, T., Hansen, H.S., Engelholm, S.A., Nystrom, H. (2005) In vivo dose verification of IMRT treated head and neck cancer patients, Acta Oncol. 44, 572-578. Google ScholarPubMed
Kairn, T., Dwyer, M., Warne, D., Markwell, T.S., Trapp, J.V., Fielding, A.L. (2009) CTCombine: Rotating and combining CT data with an accurate detector model, to simulate radiotherapy portal imaging at non-zero beam angles. In: Engineering and Physical Sciences in Medicine Conference, November 8–12, 2009, Canberra. Google Scholar
Kawrakow I., Mainegra-Hing E., Rogers D.W.O., Tessier F., Walters B. (2011) The EGSnrc Code System: Monte Carlo Simulation of Electron and Photon Transport, Manual, National Research Council of Canada.
Low, D.A., et al. (1998) A technique for the quantitative evaluation of dose distributions, Med. Phys. 25 (5), 656-661. Google ScholarPubMed
Pham T.M. (2009) Simulation of the transmitted dose in an EPID using a Monte Carlo Method, Ph.D. thesis, Adelaide University, Australia.
Podgorsak E.B. (2005) Radiation Oncology Physics: A Handbook for Teachers and Students. IAEA, Vienna, ISBN 92-0-107304-6.
Reich P.D. (2008) A theoretical evaluation of transmission dosimetry in 3D conformal radiotherapy, Ph.D. thesis, Adelaide University.
Rogers D.W.O., Walters B., Kawrakow I. (2009) BEAMnrc Users Manual, National Research Council of Canada.
Rogers D.W.O., Walters B., Kawrakow I. (2009) DOSXYZnrc Users Manual, National Research Council of Canada.
Schneider, U., Pedroni, E., Lomax, A. (1996) The calibration of CT Hounsfield units for radiotherapy treatment planning, Phys. Med. Biol. 41, 111-124. Google ScholarPubMed
Sheikh-Bagheri, D., Rogers, D.W.O. (2002) Sensitivity of megavoltage photon beam Monte Carlo simulations to electron beam and other parameters, Med. Phys. 29 (3), 379-390. Google ScholarPubMed
Siebers, J.V., Kim, J.-O., Ko, L., Keall, P.J., Mohan, R. (2004) Monte Carlo computation of dosimetric amorphous silicon electronic portal images, Med. Phys. 31 (7), 2135-2146. Google ScholarPubMed
Spezi, E., Lewis, D.G. (2002) Full forward Monte Carlo calculation of portal dose from MLC collimated treatment beams, Phys. Med. Biol. 47, 377-390. Google ScholarPubMed
van Elmpt, W., McDermott, L., Nijsten, S., Wendling, M., Lambin, P., Mijnheer, B. (2008) A literature review of electronic portal imaging for radiotherapy dosimetry, Radiother. Oncol. 88, 289-309. Google ScholarPubMed
van Zijtveld, M., Dirkx, M., Breuers, M., de Boer, H., Heijmen, B. (2009) Portal dose image prediction for in vivo treatment verification completely based on EPID measurements, Med. Phys. 36 (3), 946-952. Google ScholarPubMed
Varian Medical Systems (2007) Portal Imaging And Portal Dosimetry Reference Guide.
Varian Medical Systems (2008) Eclipse Algorithms Reference Guide.