Introduction: Advanced radiotherapy methods include Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) requiring stringent quality assurance (QA) to ensure accurate dose delivery. This study assesses the effectiveness of IMRT and VMAT dosage verification by gamma index analysis and capability index (Cpml), which are statistical process control (SPC) tools, to assess QA process reliability and compare dosimetrical outcomes for head and neck and rectal cancer treatment plans. MaterialsandMethods: For 28 cases of head and neck (14 IMRT and 14 VMAT) were generated utilizing treatment planning system (TPS) Eclipse, which delivered 6 MV photon beam linear accelerator (Varian, Clinac IX). Dose distributions were measured using an aSi-1000 electronic portal imaging device (EPID) and OCTAVIUS Detector 1500 2D array, compared against TPS calculations using gamma index criteria (3%/3 mm). Control charts and Cpml evaluated QA process stability for 25 cases. Dosimetrical comparisons for rectal cancer assessed planning target volume coverage, organ-at-risk doses, and monitor units. Result: For head and neck the gamma passing rates showed strong agreement, with means of 99.24% ± 0.37 (EPID) and 98.76% ± 0.61 (2D array) for IMRT, and 99.00% ± 0.38 (EPID) and 98.91% ± 0.43 (2D array) for VMAT. For rectal cancer the capability index (Cpml) values of 1.36 (IMRT) and 1.47 (VMAT) indicated optimal QA performance. VMAT plans for rectal cancer reduced MUs and treatment time by approximately 50% while achieving comparable PTV coverage and OAR sparing. Conclusion: VMAT demonstrates efficiency advantages over IMRT, with robust QA processes, supported by SPC and capability index assessments, enhancing treatment precision and patient outcomes.
References
[1]
Bucci, M.K., Bevan, A. and Roach, M. (2005) Advances in Radiation Therapy: Conventional to 3D, to IMRT, to 4D, and beyond. CA: A Cancer Journal for Clinicians, 55, 117-134. https://doi.org/10.3322/canjclin.55.2.117
[2]
Konstantinou, E., Varveris, A., Solomou, G., Antoniadis, C., Tolia, M. and Mazonakis, M. (2024) Radiation Dose to Critical Cardiac Structures from Three-Dimensional Conformal Radiation Therapy (3D-CRT), Intensity-Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) Techniques for Left-Sided Breast Cancer. Journal of Personalized Medicine, 14, Article 63. https://doi.org/10.3390/jpm14010063
[3]
Alvarez-Moret, J., Pohl, F., Koelbl, O. and Dobler, B. (2010) Evaluation of Volumetric Modulated Arc Therapy (VMAT) with Oncentra Masterplan® for the Treatment of Head and Neck Cancer. Radiation Oncology, 5, Article No. 110. https://doi.org/10.1186/1748-717x-5-110
[4]
Bailey, D.W., Kumaraswamy, L., Bakhtiari, M., Malhotra, H.K. and Podgorsak, M.B. (2012) EPID Dosimetry for Pretreatment Quality Assurance with Two Commercial Systems. Journal of Applied Clinical Medical Physics, 13, 82-99. https://doi.org/10.1120/jacmp.v13i4.3736
[5]
Onal, C., Arslan, G., Parlak, C. and Sonmez, S. (2014) Comparison of IMRT and VMAT Plans with Different Energy Levels Using Monte-Carlo Algorithm for Prostate Cancer. Japanese Journal of Radiology, 32, 224-232. https://doi.org/10.1007/s11604-014-0291-3
[6]
Palta, J.R., Liu, C. and Li, J.G. (2008) Quality Assurance of Intensity-Modulated Radiation Therapy. International Journal of Radiation Oncology, Biology, Physics, 71, S108-S112. https://doi.org/10.1016/j.ijrobp.2007.05.092
[7]
Klein, E.E., Hanley, J., Bayouth, J., Yin, F., Simon, W., Dresser, S., et al. (2009) Task Group 142 Report: Quality Assurance of Medical Acceleratorsa). Medical Physics, 36, 4197-4212. https://doi.org/10.1118/1.3190392
[8]
Saminathan, S., Manickan, R., Chandraraj, V. and Supe, S.S. (2010) Dosimetric Study of 2D Ion Chamber Array Matrix for the Modern Radiotherapy Treatment Verification. Journal of Applied Clinical Medical Physics, 11, 116-127. https://doi.org/10.1120/jacmp.v11i2.3076
[9]
Low, D.A., Harms, W.B., Mutic, S. and Purdy, J.A. (1998) A Technique for the Quantitative Evaluation of Dose Distributions. Medical Physics, 25, 656-661. https://doi.org/10.1118/1.598248
[10]
Mohamed, I.E., Ibrahim, A.G., Zidan, H.M., El-Bahkiry, H.S. and El-sahragti, A.Y. (2018) Physical Dosimetry of Volumetric Modulated Arc Therapy (VMAT) Using EPID and 2D Array for Quality Assurance. The Egyptian Journal of Radiology and Nuclear Medicine, 49, 477-484. https://doi.org/10.1016/j.ejrnm.2018.02.003
[11]
Pawlicki, T., Whitaker, M. and Boyer, A.L. (2005) Statistical Process Control for Radiotherapy Quality Assurance. Medical Physics, 32, 2777-2786. https://doi.org/10.1118/1.2001209
[12]
Nordström, F., Af Wetterstedt, S., Johnsson, S., Ceberg, C. and Bäck, S.Å.J. (2012) Control Chart Analysis of Data from a Multicenter Monitor Unit Verification Study. Radiotherapy and Oncology, 102, 364-370. https://doi.org/10.1016/j.radonc.2011.11.016
[13]
Rajasekaran, D., Jeevanandam, P., Sukumar, P., Ranganathan, A., Johnjothi, S. and Nagarajan, V. (2015) A Study on the Correlation between Plan Complexity and Gamma Index Analysis in Patient Specific Quality Assurance of Volumetric Modulated Arc Therapy. Reports of Practical Oncology & Radiotherapy, 20, 57-65. https://doi.org/10.1016/j.rpor.2014.08.006
[14]
Roy, A., Cutright, D., Gopalakrishnan, M., Yeh, A.B. and Mittal, B.B. (2020) A Risk-Adjusted Control Chart to Evaluate Intensity Modulated Radiation Therapy Plan Quality. Advances in Radiation Oncology, 5, 1032-1041. https://doi.org/10.1016/j.adro.2019.11.006
[15]
Pawlicki, T., Yoo, S., Court, L.E., McMillan, S.K., Rice, R.K., Russell, J.D., et al. (2008) Moving from IMRT QA Measurements toward Independent Computer Calculations Using Control Charts. Radiotherapy and Oncology, 89, 330-337. https://doi.org/10.1016/j.radonc.2008.07.002
[16]
Sanghangthum, T., Suriyapee, S., Srisatit, S. and Pawlicki, T. (2013) Statistical Process Control Analysis for Patient-Specific IMRT and VMAT QA. Journal of Radiation Research, 54, 546-552. https://doi.org/10.1093/jrr/rrs112
[17]
Raveendran, V., Anjana, P.T., Bhasi, S., Ranjith, C.P. and Kinhikar, R.A. (2023) Moving towards Process-Based Radiotherapy Quality Assurance Using Statistical Process Control. PhysicaMedica, 112, Article 102651. https://doi.org/10.1016/j.ejmp.2023.102651
[18]
Jacob, P. (2024) Comparison of Arccheck and Portal Dosimetry in Dose Verification for Intensity Modulated Radiotherapy (IMRT) and Rapidarc Plans. Journal of Oncology Research Reviews & Reports, 5, 1-5. https://doi.org/10.47363/jonrr/2024(5)179
[19]
Webster, M., Podgorsak, A., Li, F., Zhou, Y., Jung, H., Yoon, J., et al. (2025) New Approaches in Radiotherapy. Cancers, 17, Article No. 1980. https://doi.org/10.3390/cancers17121980
[20]
Das, S., Kharade, V., Pandey, V., KV, A., Pasricha, R.K. and Gupta, M. (2022) Gamma Index Analysis as a Patient-Specific Quality Assurance Tool for High-Precision Radiotherapy: A Clinical Perspective of Single Institute Experience. Cureus, 14, e30885. https://doi.org/10.7759/cureus.30885
[21]
Depuydt, T., Van Esch, A. and Huyskens, D.P. (2002) A Quantitative Evaluation of IMRT Dose Distributions: Refinement and Clinical Assessment of the Gamma Evaluation. Radiotherapy and Oncology, 62, 309-319.
[22]
Spezi, E. and Lewis, D.G. (2006) Gamma Histograms for Radiotherapy Plan Evaluation. Radiotherapy and Oncology, 79, 224-230. https://doi.org/10.1016/j.radonc.2006.03.020
[23]
Miften, M., Olch, A., Mihailidis, D., Moran, J., Pawlicki, T., Molineu, A., et al. (2018) Tolerance Limits and Methodologies for IMRT Measurement-Based Verification QA: Recommendations of AAPM Task Group No. 218. Medical Physics, 45, e53-e83. https://doi.org/10.1002/mp.12810
[24]
Agazaryan, N., Solberg, T.D. and DeMarco, J.J. (2003) Patient Specific Quality Assurance for the Delivery of Intensity Modulated Radiotherapy. JournalofAppliedClinicalMedicalPhysics, 4, 40-50. https://doi.org/10.1120/jacmp.v4i1.2540
[25]
Ryan, T.P. (2006) Mastering Statistical Process Control: A Handbook for Performance Improvement Using Cases. Journal of Quality Technology, 38, 294-296.
[26]
Pawlicki, T., Chera, B., Ning, T. and Marks, L.B. (2012) The Systematic Application of Quality Measures and Process Control in Clinical Radiation Oncology. Seminars in Radiation Oncology, 22, 70-76. https://doi.org/10.1016/j.semradonc.2011.09.006
[27]
Chan, L.K., Cheng, S.W. and Spiring, F.A. (1988) A New Measure of Process Capability: C pm. Journal of Quality Technology, 20, 162-175. https://doi.org/10.1080/00224065.1988.11979102
[28]
Chaikh, A. and Balosso, J. (2016) Statistical Control Process to Compare and Rank Treatment Plans in Radiation Oncology: Impact of Heterogeneity Correction on Treatment Planning in Lung Cancer. Translational Lung Cancer Research, 5, 688-694. https://doi.org/10.21037/tlcr.2016.09.04
[29]
Wheeler, D.J. and Chambers, D.S. (1992) Understanding Statistical Process Control. 3rd Edition, SPC Press.
[30]
Pillet, M., Rochon, S. and Duclos, E. (1997) SPC—Generalization of Capability Index C pm: Case of Unilateral Tolerances. Quality Engineering, 10, 171-1766.
[31]
Fuangrod, T., Greer, P.B., Woodruff, H.C., Simpson, J., Bhatia, S., Zwan, B., et al. (2016) Investigation of a Real-Time EPID-Based Patient Dose Monitoring Safety System Using Site-Specific Control Limits. Radiation Oncology, 11, Article No. 106. https://doi.org/10.1186/s13014-016-0682-y
[32]
Sharma, D.S., Mhatre, V., Heigrujam, M., Talapatra, K. and Mallik, S. (2010) Portal Dosimetry for Pretreatment Verification of IMRT Plan: A Comparison with 2D Ion Chamber Array. Journal of Applied Clinical Medical Physics, 11, 238-248. https://doi.org/10.1120/jacmp.v11i4.3268
[33]
Jayesh, K., Ganesh, T., Suganthi, D., Mohan, R., Rakesh, C.J., Sarojkumar, D.M. and Jacob, S.J. (2013) Dosimetric Comparison of aSi1000 EPID and ImatriXX 2-D Array System for Volumetric Modulated Arc and Intensity Modulated Radiotherapy Patient Specific Quality Assurance, World Academy of Science, Engineering and Technology. International Journal of Physical and Mathematical Sciences, 7.
[34]
Goldsmith, C. and Gaya, A. (2012) Stereotactic Ablative Body Radiotherapy (SABR) for Primary and Secondary Lung Tumours. Cancer Imaging, 12, 351-360. https://doi.org/10.1102/1470-7330.2012.9015
