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Das S, Kharade V, Pandey VP, KV A, Pasricha RK, Gupta M. Gamma Index Analysis as a Patient-Specific Quality Assurance Tool for High-Precision Radiotherapy: A Clinical Perspective of Single Institute Experience. Cureus 2022; 14:e30885. [PMID: 36337776 PMCID: PMC9626372 DOI: 10.7759/cureus.30885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2022] [Indexed: 11/07/2022] Open
Abstract
Purpose Patient-specific quality assurance (QA) by gamma (γ) analysis is an important component of high-precision radiotherapy. It is important to standardize institute-specific protocol. In this study, we describe our institutional experience of patient-specific QA for high-precision radiotherapy from a clinical perspective. Methods The planning data of 56 patients treated with intensity-modulated radiotherapy (IMRT)/volumetric modulated arc therapy (VMAT) were included. γ index analysis was done using Octavius 4D IMRT QA phantom (PTW, Freiburg, Germany) using 3 mm/3% criteria. Local, global, and volumetric gammas were calculated and compared. The relationship of γ index in the transverse, coronal, and sagittal direction and anatomical region of treatment was explored. Results Global three-dimensional (3D) γ indices in the coronal, sagittal, and transverse axes were 96.73 ± 2.35, 95.66 ± 3.01, and 93.36 ± 4.87 (p < 0.05). The average local two-dimensional (2D) γ index was 78.23 ± 5.44 and the global γ index was 92.41 ± 2.41 (p < 0.005). The average local 3D γ index was 84.99 ± 4.24 and the global 3D γ index was 95.25 ± 1.72 (p < 0.005, paired t-test). The average local volumetric γ index was 84.29 ± 4.73 and the global volumetric γ index was 95.96 ± 2.08 (p < 0.005). 3D global gamma index was significantly different in different anatomical regions (p < 0.05). Conclusion Our study shows that γ index analysis is a useful parameter for routine clinical IMRT QA. The choice of type of γ index depends on the context of use and degree of stringency in measurement. Average 2D and 3D global γ were different in anatomical regions. The average 3D γ index was significantly different in axes. No difference was observed with techniques of IMRT/VMAT. Localization of failed points in CT anatomy can be advantageous for clinical decision-making.
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Diamantopoulos S, Platoni K, Patatoukas G, Karaiskos P, Kouloulias V, Efstathopoulos E. Treatment plan verification: A review on the comparison of dose distributions. Phys Med 2019; 67:107-115. [PMID: 31706146 DOI: 10.1016/j.ejmp.2019.10.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 10/25/2022] Open
Abstract
PURPOSE The aim of this review article is to provide a useful reference for dose comparison techniques within the frame of treatment plan verification. Each technique is presented with a general description given along with advantages and disadvantage and the rationale for its development. METHODS The review was conducted in PubMed from 1993 to 2019 including articles referring to the methodology of dose comparison for treatment plan verification. RESULTS The search identified thirty-one dose comparison methods that were categorized according to the number of physical parameters that take into account for dose comparison. CONCLUSIONS Among the available methods for the comparison of two dose distributions, the γ-analysis (gamma analysis) has been widely adopted as the gold standard in verification procedures. However, due to various intrinsic limitations of gamma index, the development of a better metric taking into account both statistical and in clinical parameters is required.
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Affiliation(s)
- Stefanos Diamantopoulos
- 2nd Department of Radiology, University General Hospital "Attikon", National and Kapodistrian, University of Athens, Greece.
| | - Kalliopi Platoni
- 2nd Department of Radiology, University General Hospital "Attikon", National and Kapodistrian, University of Athens, Greece
| | - Georgios Patatoukas
- 2nd Department of Radiology, University General Hospital "Attikon", National and Kapodistrian, University of Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Greece
| | - Vassilis Kouloulias
- 2nd Department of Radiology, University General Hospital "Attikon", National and Kapodistrian, University of Athens, Greece
| | - Efstathios Efstathopoulos
- 2nd Department of Radiology, University General Hospital "Attikon", National and Kapodistrian, University of Athens, Greece
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Sun WZ, Zhang DD, Peng YL, Chen L, Kang DH, Wang B, Deng XW. Retrospective dosimetry study of intensity-modulated radiation therapy for nasopharyngeal carcinoma: measurement-guided dose reconstruction and analysis. Radiat Oncol 2018; 13:42. [PMID: 29544512 PMCID: PMC5856312 DOI: 10.1186/s13014-018-0993-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/07/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Conventional phantom-based planar dosimetry (2D-PBD) quality assurance (QA) using gamma pass rate (GP (%)) is inadequate to reflect clinically relevant dose error in intensity-modulated radiation therapy (IMRT), owing to a lack of information regarding patient anatomy and volumetric dose distribution. This study aimed to evaluate the dose distribution accuracy of IMRT delivery for nasopharyngeal carcinoma (NPC), which passed the 2D-PBD verification, using a measurement-guided 3D dose reconstruction (3D-MGR) method. METHODS Radiation treatment plans of 30 NPC cases and their pre-treatment 2D-PBD data were analyzed. 3D dose distribution was reconstructed on patient computed tomography (CT) images using the 3DVH software and compared to the treatment plans. Global and organ-specific dose GP (%), and dose-volume histogram (DVH) deviation of each structure was evaluated. Interdependency between GP (%) and the deviation of the volumetric dose was studied through correlation analysis. RESULTS The 3D-MGR achieved global GP (%) similar to conventional 2D-PBD in the same criteria. However, structure-specific GP (%) significantly decreased under stricter criteria, including the planning target volume (PTV). The average deviation of all inspected dose volumes (DV) and volumetric dose (VD) parameters ranged from - 2.93% to 1.17%, with the largest negative deviation in V100% of the PTVnx of - 15.66% and positive deviation in D1cc of the spinal cord of 6.66%. There was no significant correlation between global GP (%) of 2D-PBD or 3D-MGR and the deviation of the most volumetric dosimetry parameters (DV or VD), when the Pearson's coefficient value of 0.8 was used for correlation evaluation. CONCLUSION Even upon passing the pre-treatment phantom based dosimetric QA, there could still be risk of dose error like under-dose in PTVnx and overdose in critical structures. Measurement-guided 3D volumetric dosimetry QA is recommended as the more clinically efficient verification for the complicated NPC IMRT.
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Affiliation(s)
| | | | - Ying-Lin Peng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China
| | - Li Chen
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China
| | - De-Hua Kang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China
| | - Bin Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China
| | - Xiao-Wu Deng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Department of Radiation Oncology, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, People's Republic of China.
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Hamatani N, Sumida I, Takahashi Y, Oda M, Seo Y, Isohashi F, Tamari K, Ogawa K. Three-dimensional dose prediction and validation with the radiobiological gamma index based on a relative seriality model for head-and-neck IMRT. JOURNAL OF RADIATION RESEARCH 2017; 58:701-709. [PMID: 28430990 PMCID: PMC5737806 DOI: 10.1093/jrr/rrx017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 11/30/2016] [Indexed: 06/07/2023]
Abstract
This study proposes a quality assurance (QA) method incorporating radiobiological factors based on the QUANTEC-determined tumor control probability and the normal tissue complication probability (NTCP) of head-and-neck intensity-modulated radiation therapy (HN-IMRT). Per-beam measurements were conducted for 20 cases using a 2D detector array. Three-dimensional predicted dose distributions within targets and organs at risk were reconstructed based on the per-beam QA results derived from differences between planned and measured doses. Under the predicted dose distributions, the differences between the physical and radiobiological gamma indices (PGI and RGI, respectively) based on the relative seriality (RS) model were evaluated. The NTCP values in the RS and Niemierko models were compared. The dose covers 98% (D98%) of the clinical target volume (CTV) decreased by 3.2% (P < 0.001), and the mean dose of the ipsilateral parotid increased by 6.3% (P < 0.001) compared with the original dose. RGI passing rates in the CTV and brain stem were greater than PGI ones by 5.8% (P < 0.001) and 2.0% (P < 0.001), respectively. The RS model's average NTCP values for the ipsilateral and contralateral parotids under the original dose were smaller than those of the Niemierko model by 9.0% (P < 0.001) and 7.0% (P < 0.001), respectively. The 3D predicted dose evaluation with RGI based on the RS model was introduced for QA of HN-IMRT, leading to dose evaluation for each organ with consideration of the radiobiological effect. This method constitutes a rational way to perform QA of HN-IMRT in clinical practice.
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Affiliation(s)
- Noriaki Hamatani
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Iori Sumida
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Yutaka Takahashi
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Michio Oda
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
- Department of Radiology, Osaka University Hospital, 2-15 Yamada-oka, Suita, Osaka 565-0871,Japan
| | - Yuji Seo
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Fumiaki Isohashi
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Keisuke Tamari
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Graduate School of Medicine, Osaka University, 2-2 (D10) Yamada-oka, Suita, Osaka 565-0871, Japan
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Sumida I, Yamaguchi H, Kizaki H, Aboshi K, Tsujii M, Yoshikawa N, Yamada Y, Suzuki O, Seo Y, Isohashi F, Yoshioka Y, Ogawa K. Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution. Int J Radiat Oncol Biol Phys 2015; 92:779-86. [DOI: 10.1016/j.ijrobp.2015.02.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 01/31/2015] [Accepted: 02/23/2015] [Indexed: 10/23/2022]
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