Performance Evaluation of the Siemens Electronic Portal Imaging Device for IMRT Plan Verification
Affiliation(s)
1 Department of Radiation Oncology, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa. 2 Department of Biomedical Physics, Faculty of Health Sciences, Al-Neelain University, Khartoum, Sudan.
1 Department of Radiation Oncology, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa. 2 Department of Biomedical Physics, Faculty of Health Sciences, Al-Neelain University, Khartoum, Sudan.
ABSTRACT
A commercially available amorphous Silicon Electronic Portal imaging device (aSi-EPID) installed onto Siemens Oncor Linear accelerator was evaluated with the objective to be implemented for IMRT quality assurance. EPID properties were investigated; these include reproducibility, dependences between the relative EPID responses and field size, dose rate were studied for both photon beams. To determine the inherent build-up of the EPID, varied thickness of Solid-water was placed onto the detector surface and changes in EPID signals were investigated. EPID measurements were compared with ionization chamber measurements (type 30013) connected to a UNIDOS electrometer (PTW-Freiberg) in Water phantom. The use of EPID dose maps was tested by comparing it with TPS-calculated one for IMRT plan applying gamma criteria of 3%/3mm. The results demonstrated that the aSi-EPID signals were reproducible, and response to the applied MUs were linear up to 100 MUs, and then the response became stable for MUs higher than 200, detector should be calibrated in this range. The results showed a clear dependency on the field size and energy. The dosimetric properties measured in this work shows promise that the aSi-EPID can be used for IMRT verifications.
A commercially available amorphous Silicon Electronic Portal imaging device (aSi-EPID) installed onto Siemens Oncor Linear accelerator was evaluated with the objective to be implemented for IMRT quality assurance. EPID properties were investigated; these include reproducibility, dependences between the relative EPID responses and field size, dose rate were studied for both photon beams. To determine the inherent build-up of the EPID, varied thickness of Solid-water was placed onto the detector surface and changes in EPID signals were investigated. EPID measurements were compared with ionization chamber measurements (type 30013) connected to a UNIDOS electrometer (PTW-Freiberg) in Water phantom. The use of EPID dose maps was tested by comparing it with TPS-calculated one for IMRT plan applying gamma criteria of 3%/3mm. The results demonstrated that the aSi-EPID signals were reproducible, and response to the applied MUs were linear up to 100 MUs, and then the response became stable for MUs higher than 200, detector should be calibrated in this range. The results showed a clear dependency on the field size and energy. The dosimetric properties measured in this work shows promise that the aSi-EPID can be used for IMRT verifications.
Cite this paper
Yousif, Y. and Rensburg, A. (2015) Performance Evaluation of the Siemens Electronic Portal Imaging Device for IMRT Plan Verification. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 4, 215-223. doi: 10.4236/ijmpcero.2015.43026.
Yousif, Y. and Rensburg, A. (2015) Performance Evaluation of the Siemens Electronic Portal Imaging Device for IMRT Plan Verification. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 4, 215-223. doi: 10.4236/ijmpcero.2015.43026.
References
[1] Nicolini, G., Vanetti, E., Clivio, A., Fogliata, A., Boka, G. and Cozzi, L. (2006) Testing the Portal Imager GLA as Algorithm for Machine Quality Assurance. Radiation Oncology, 3, 1-20. [2] Greer, P.B. and Barnes, M.P. (2007) Investigation of an Amorphous Silicon EPID for Measurement and Quality Assurance of Enhanced Dynamic Wedge. Physics in Medicine and Biology, 52, 1075-1087.
http://dx.doi.org/10.1088/0031-9155/52/4/014 [3] Heijmen, B.J., Pasma, K.L., Kroonwijk, M. and Altohof, V.G.M. (1995) Portal Dose Measurement in Radiotherapy Using an Electronic Portal Imaging Device (EPID). Physics in Medicine and Biology, 40, 1943-1955.
http://dx.doi.org/10.1088/0031-9155/40/11/012 [4] Chen, J., Chuang, C.F., Morin, O., Aubin, M. and Pouliot, J. (2006) Calibration of an Amorphous-Silicon Flat Panel Portal Imager for Exit-Beam Dosimetry. Medical Physics, 33, 3095-3105.
http://dx.doi.org/10.1118/1.2168294 [5] Partridge, M., Hesse, B.-M. and Muller, L. (2002) A Performance Comparison of Direct-and Indirect-Detection Flat Panel Imager. Nuclear Instruments and Methods in Physics Research, 48, 351-363.
http://dx.doi.org/10.1016/S0168-9002(01)02023-X [6] Chang, J., Mageras, G.S., Chui, C.S., Ling, C.C. and Lutz, W. (2000) Relative Profile and Dose Verification of Intensity-Modulated Radiation Therapy. International Journal of Radiation Oncology * Biology * Physics, 47, 231-240.
http://dx.doi.org/10.1016/S0360-3016(99)00555-6 [7] Pasma, K.L., Kroonwijk, M., de Boer, J.C.J., Visser, A.G. and Heijmen, B.J. (1998) Accurate Portal Dose Measurement with a Fluoroscopic Electronic Portal Imaging Device (EPID) for Open and Wedged Beams and Dynamic Multileaf Collimation. Physics in Medicine and Biology, 43, 2047-2060.
http://dx.doi.org/10.1088/0031-9155/43/8/004 [8] Greer, P. and Popescu, C. (2003) Dosimetric Properties of an Amorphous Silicon Electronic Portal Imaging Device for Verification of Dynamic Intensity Modulated Radiation Therapy. Medical Physics, 30, 1618-1627.
http://dx.doi.org/10.1118/1.1582469 [9] Grein, E.E., Lee, R. and Luchka, K. (2002) An Investigation of a New Amorphous Silicon Electronic Portal Imaging Device for Transit Dosimetry. Medical Physics, 29, 2262-2628.
http://dx.doi.org/10.1118/1.1508108 [10] Van Esch, A., Depuydt, T. and Huyskens, D.P. (2004) The Use of an aSi-Based EPID for Routine Absolute Dosimetric Pre-Treatment Verification of Dynamic IMRT Fields. Radiotherapy and Oncology, 71, 223-234.
http://dx.doi.org/10.1016/j.radonc.2004.02.018 [11] Podesta, M., Nijsten, S.M., Snaith, J., Orlandini, M., Lustberg, T., Emans, D., et al. (2012) Measured vs. Simulated Portal Images for Low MU Fields on Three Accelerator Types: Possible Consequences for 2D Portal Dosimetry. Medical Physics, 39, 7470-7479.
http://dx.doi.org/10.1118/1.4761950 [12] Warkentin, B., Rathee, S. and Steciw, S. (2012) 2D Lag and Signal Nonlinearity Correction in an Amorphous Silicon EPID and Their Impact on Pretreatment Dosimetric Verification. Medical Physics, 39, 6597-6608.
http://dx.doi.org/10.1118/1.4757582 [13] Louwe, R.J., Tielenburg, R., van Ingen, K.M., Mijneer, B.J. and van Herk, M.B. (2004) The Stability of Liquid-Filled Matrix Ionization Chamber Electronic Portal Imaging Devices for Dosimetry Purposes. Medical Physics, 31, 819-827.
http://dx.doi.org/10.1118/1.1668411 [14] Antonuk, L.E., El-Mohri, Y. and Huang, W. (1998) Initial Performance Evaluation of an Indirect-Detection, Active Matrix Flat-Panel Imager (AMFPI) Prototype for Megavoltage Imaging. International Journal of Radiation Oncology*Biology*Physics, 42, 437-454.
http://dx.doi.org/10.1016/S0360-3016(98)00210-7 [15] El-Mohri, Y., Antonuk, L.E., Yorkston, J., Jee, K.-W., Maolinbay, M., Lam, K.L. and Siewerdsen, J.H. (1999) Relative Dosimetry Using Active Matrix Flat-Panel Imager (AMFPI) Technology. Medical Physics, 26, 1530-1541.
http://dx.doi.org/10.1118/1.598649 [16] Winkler, P., Hefner, A. and Georg, D. (2005) Dose-Response Characteristics of an Amorphous Silicon EPID. Medical Physics, 32, 3095-3105.
http://dx.doi.org/10.1118/1.2040711 [17] McDermott, L.N., Nijsten, S.M., Sonke, J.J., Partridge, M., Herk, M. and Mijnheer, B.J. (2006) Comparison of Ghosting Effects for Three Commercial a-Si Electronic Portalimaging Devices. Medical Physics, 33, 2448-2451.
http://dx.doi.org/10.1118/1.2207318 [18] McDermott, N.L., Louwe, R.J., Sonke, J.J., van Herk, M. and Mijnheer, B.J. (2004) Dose-Response and Ghosting Effects of an Amorphous Silicon Electronic Portal Imaging Device. Medical Physics, 31, 285-295.
http://dx.doi.org/10.1118/1.1637969 [19] Nicolini, G., Fogliata, A., Vanetti, E., Clivio, A. and Vetterli, D. (2006) GLAaS: An Absolute Dose Calibration Algorithm for an Amorphous Silicon Portal Imager. Applications to IMRT Verifications. Medical Physics, 33, 2839-2851.
http://dx.doi.org/10.1118/1.2218314 [20] Nijsten, S.M.J.J., Van Elmpt, W.J.C., Jacobs, M., Mijnheer, B.J., Dekker, A.L.A.J., Lambin, P. and Minken, A.W.H. (2007) A Global Calibration Model for a-Si EPIDs Used for Transit Dosimetry. Medical Physics, 34, 2872-2884.
http://dx.doi.org/10.1118/1.2776244 [21] Van Elmpt, W., Ezzell, G.A. and Orton, C.G. (2009) EPID Dosimetry Must Soon Become an Essential Component of IMRT Quality Assurance. Medical Physics, 36, 4325-4327.
http://dx.doi.org/10.1118/1.3213082 [22] Nijsten, S.M., Mijnheer, B.J., Dekker, A.L., Lambin, P. and Minken, A.W. (2007) Routine Individualized Patient Dosimetry Using Electronic Portal Imaging Devices. Radiotherapy and Oncology, 83, 65-75.
http://dx.doi.org/10.1016/j.radonc.2007.03.003 [23] Van Elmpt, W., McDermott, L.N., Nijsten, S., Wendling, M., Lambin, P. and Mijnheer, B.J. (2008) A Literature Review of Electronic Portal Imaging for Radiotherapy Dosimetry. Radiotherapy and Oncology, 88, 289-309.
http://dx.doi.org/10.1016/j.radonc.2008.07.008 [24] van Elmpt, W., Nijsten, S., Mijnheer, B.J., Dekker, A. and Lamb, A. (2008) The Next Step in Patient-Specific QA: 3D Dose Verification of Conformal and Intensity-Modulated RT Based on EPID Dosimetry and Monte Carlo Dose Calculations. Radiotherapy and Oncology, 86, 86-92.
http://dx.doi.org/10.1016/j.radonc.2007.11.007 [25] Cilla, S., Fidanzio, A., Greco, F., Sabatino, D., Russo, A., Gargiulo, L., Azario, L. and Piermattei, A. (2010) Correlation Functions for Elekta aSi EPIDs Used as Transit Dosimeter for Open Fields. Journal of Applied Clinical Medical Physics, 12, 218-233. [26] Deshpande, S., Vial, P. and Holloway, L. (2011) 2-D Radiation Therapy Dosimetry Using EPIDs: Dose Response Variation between 3 Siemens Electronic Portal Imaging Devices (EPIDs). Radiation Measurements, 46, 1916-1919.
http://dx.doi.org/10.1016/j.radmeas.2011.08.006 [27] Deshpande, S., Holloway, L., Metcalfe, P. and Vial, P. (2012) An Integrated 2-D Dosimeter and Electronic Portal Imaging Device for in Vivo Dosimetry: A Feasibility Study. International Journal of Radiation Oncology*Biology* Physics, 84, S764.
http://dx.doi.org/10.1016/j.ijrobp.2012.07.2044 [28] Van Esch, A., Huyskens, D.P., Hirschi, L., Scheib, S. and Baltesn, C. (2013) Optimized Varian aSi Portal Dosimetry: Development of Datasets for Collective Use. Journal of Applied Clinical Medical Physics, 14, 4286. [29] ONCOR Impression Operator Manual, Siemens Medical Solutions USA, Inc., Malvern, PA. [30] Radiological Imaging Technology (RIT). Colorado Springs, CO.
http://www.radimage.com/ [31] Greer, P.B. (2007) Off-Axis Dose Response Characteristics of an a-Si Electronic Portal Imaging Device. Medical Physics, 34, 3815-3824.
http://dx.doi.org/10.1118/1.2779944
[1] Nicolini, G., Vanetti, E., Clivio, A., Fogliata, A., Boka, G. and Cozzi, L. (2006) Testing the Portal Imager GLA as Algorithm for Machine Quality Assurance. Radiation Oncology, 3, 1-20. [2] Greer, P.B. and Barnes, M.P. (2007) Investigation of an Amorphous Silicon EPID for Measurement and Quality Assurance of Enhanced Dynamic Wedge. Physics in Medicine and Biology, 52, 1075-1087.
http://dx.doi.org/10.1088/0031-9155/52/4/014 [3] Heijmen, B.J., Pasma, K.L., Kroonwijk, M. and Altohof, V.G.M. (1995) Portal Dose Measurement in Radiotherapy Using an Electronic Portal Imaging Device (EPID). Physics in Medicine and Biology, 40, 1943-1955.
http://dx.doi.org/10.1088/0031-9155/40/11/012 [4] Chen, J., Chuang, C.F., Morin, O., Aubin, M. and Pouliot, J. (2006) Calibration of an Amorphous-Silicon Flat Panel Portal Imager for Exit-Beam Dosimetry. Medical Physics, 33, 3095-3105.
http://dx.doi.org/10.1118/1.2168294 [5] Partridge, M., Hesse, B.-M. and Muller, L. (2002) A Performance Comparison of Direct-and Indirect-Detection Flat Panel Imager. Nuclear Instruments and Methods in Physics Research, 48, 351-363.
http://dx.doi.org/10.1016/S0168-9002(01)02023-X [6] Chang, J., Mageras, G.S., Chui, C.S., Ling, C.C. and Lutz, W. (2000) Relative Profile and Dose Verification of Intensity-Modulated Radiation Therapy. International Journal of Radiation Oncology * Biology * Physics, 47, 231-240.
http://dx.doi.org/10.1016/S0360-3016(99)00555-6 [7] Pasma, K.L., Kroonwijk, M., de Boer, J.C.J., Visser, A.G. and Heijmen, B.J. (1998) Accurate Portal Dose Measurement with a Fluoroscopic Electronic Portal Imaging Device (EPID) for Open and Wedged Beams and Dynamic Multileaf Collimation. Physics in Medicine and Biology, 43, 2047-2060.
http://dx.doi.org/10.1088/0031-9155/43/8/004 [8] Greer, P. and Popescu, C. (2003) Dosimetric Properties of an Amorphous Silicon Electronic Portal Imaging Device for Verification of Dynamic Intensity Modulated Radiation Therapy. Medical Physics, 30, 1618-1627.
http://dx.doi.org/10.1118/1.1582469 [9] Grein, E.E., Lee, R. and Luchka, K. (2002) An Investigation of a New Amorphous Silicon Electronic Portal Imaging Device for Transit Dosimetry. Medical Physics, 29, 2262-2628.
http://dx.doi.org/10.1118/1.1508108 [10] Van Esch, A., Depuydt, T. and Huyskens, D.P. (2004) The Use of an aSi-Based EPID for Routine Absolute Dosimetric Pre-Treatment Verification of Dynamic IMRT Fields. Radiotherapy and Oncology, 71, 223-234.
http://dx.doi.org/10.1016/j.radonc.2004.02.018 [11] Podesta, M., Nijsten, S.M., Snaith, J., Orlandini, M., Lustberg, T., Emans, D., et al. (2012) Measured vs. Simulated Portal Images for Low MU Fields on Three Accelerator Types: Possible Consequences for 2D Portal Dosimetry. Medical Physics, 39, 7470-7479.
http://dx.doi.org/10.1118/1.4761950 [12] Warkentin, B., Rathee, S. and Steciw, S. (2012) 2D Lag and Signal Nonlinearity Correction in an Amorphous Silicon EPID and Their Impact on Pretreatment Dosimetric Verification. Medical Physics, 39, 6597-6608.
http://dx.doi.org/10.1118/1.4757582 [13] Louwe, R.J., Tielenburg, R., van Ingen, K.M., Mijneer, B.J. and van Herk, M.B. (2004) The Stability of Liquid-Filled Matrix Ionization Chamber Electronic Portal Imaging Devices for Dosimetry Purposes. Medical Physics, 31, 819-827.
http://dx.doi.org/10.1118/1.1668411 [14] Antonuk, L.E., El-Mohri, Y. and Huang, W. (1998) Initial Performance Evaluation of an Indirect-Detection, Active Matrix Flat-Panel Imager (AMFPI) Prototype for Megavoltage Imaging. International Journal of Radiation Oncology*Biology*Physics, 42, 437-454.
http://dx.doi.org/10.1016/S0360-3016(98)00210-7 [15] El-Mohri, Y., Antonuk, L.E., Yorkston, J., Jee, K.-W., Maolinbay, M., Lam, K.L. and Siewerdsen, J.H. (1999) Relative Dosimetry Using Active Matrix Flat-Panel Imager (AMFPI) Technology. Medical Physics, 26, 1530-1541.
http://dx.doi.org/10.1118/1.598649 [16] Winkler, P., Hefner, A. and Georg, D. (2005) Dose-Response Characteristics of an Amorphous Silicon EPID. Medical Physics, 32, 3095-3105.
http://dx.doi.org/10.1118/1.2040711 [17] McDermott, L.N., Nijsten, S.M., Sonke, J.J., Partridge, M., Herk, M. and Mijnheer, B.J. (2006) Comparison of Ghosting Effects for Three Commercial a-Si Electronic Portalimaging Devices. Medical Physics, 33, 2448-2451.
http://dx.doi.org/10.1118/1.2207318 [18] McDermott, N.L., Louwe, R.J., Sonke, J.J., van Herk, M. and Mijnheer, B.J. (2004) Dose-Response and Ghosting Effects of an Amorphous Silicon Electronic Portal Imaging Device. Medical Physics, 31, 285-295.
http://dx.doi.org/10.1118/1.1637969 [19] Nicolini, G., Fogliata, A., Vanetti, E., Clivio, A. and Vetterli, D. (2006) GLAaS: An Absolute Dose Calibration Algorithm for an Amorphous Silicon Portal Imager. Applications to IMRT Verifications. Medical Physics, 33, 2839-2851.
http://dx.doi.org/10.1118/1.2218314 [20] Nijsten, S.M.J.J., Van Elmpt, W.J.C., Jacobs, M., Mijnheer, B.J., Dekker, A.L.A.J., Lambin, P. and Minken, A.W.H. (2007) A Global Calibration Model for a-Si EPIDs Used for Transit Dosimetry. Medical Physics, 34, 2872-2884.
http://dx.doi.org/10.1118/1.2776244 [21] Van Elmpt, W., Ezzell, G.A. and Orton, C.G. (2009) EPID Dosimetry Must Soon Become an Essential Component of IMRT Quality Assurance. Medical Physics, 36, 4325-4327.
http://dx.doi.org/10.1118/1.3213082 [22] Nijsten, S.M., Mijnheer, B.J., Dekker, A.L., Lambin, P. and Minken, A.W. (2007) Routine Individualized Patient Dosimetry Using Electronic Portal Imaging Devices. Radiotherapy and Oncology, 83, 65-75.
http://dx.doi.org/10.1016/j.radonc.2007.03.003 [23] Van Elmpt, W., McDermott, L.N., Nijsten, S., Wendling, M., Lambin, P. and Mijnheer, B.J. (2008) A Literature Review of Electronic Portal Imaging for Radiotherapy Dosimetry. Radiotherapy and Oncology, 88, 289-309.
http://dx.doi.org/10.1016/j.radonc.2008.07.008 [24] van Elmpt, W., Nijsten, S., Mijnheer, B.J., Dekker, A. and Lamb, A. (2008) The Next Step in Patient-Specific QA: 3D Dose Verification of Conformal and Intensity-Modulated RT Based on EPID Dosimetry and Monte Carlo Dose Calculations. Radiotherapy and Oncology, 86, 86-92.
http://dx.doi.org/10.1016/j.radonc.2007.11.007 [25] Cilla, S., Fidanzio, A., Greco, F., Sabatino, D., Russo, A., Gargiulo, L., Azario, L. and Piermattei, A. (2010) Correlation Functions for Elekta aSi EPIDs Used as Transit Dosimeter for Open Fields. Journal of Applied Clinical Medical Physics, 12, 218-233. [26] Deshpande, S., Vial, P. and Holloway, L. (2011) 2-D Radiation Therapy Dosimetry Using EPIDs: Dose Response Variation between 3 Siemens Electronic Portal Imaging Devices (EPIDs). Radiation Measurements, 46, 1916-1919.
http://dx.doi.org/10.1016/j.radmeas.2011.08.006 [27] Deshpande, S., Holloway, L., Metcalfe, P. and Vial, P. (2012) An Integrated 2-D Dosimeter and Electronic Portal Imaging Device for in Vivo Dosimetry: A Feasibility Study. International Journal of Radiation Oncology*Biology* Physics, 84, S764.
http://dx.doi.org/10.1016/j.ijrobp.2012.07.2044 [28] Van Esch, A., Huyskens, D.P., Hirschi, L., Scheib, S. and Baltesn, C. (2013) Optimized Varian aSi Portal Dosimetry: Development of Datasets for Collective Use. Journal of Applied Clinical Medical Physics, 14, 4286. [29] ONCOR Impression Operator Manual, Siemens Medical Solutions USA, Inc., Malvern, PA. [30] Radiological Imaging Technology (RIT). Colorado Springs, CO.
http://www.radimage.com/ [31] Greer, P.B. (2007) Off-Axis Dose Response Characteristics of an a-Si Electronic Portal Imaging Device. Medical Physics, 34, 3815-3824.
http://dx.doi.org/10.1118/1.2779944