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Kuperman VY, Altundal Y, Kandel S, Kouskoulas TN. Dose conformity and falloff in single-lesion intracranial SRS with DCA and VMAT methods. J Appl Clin Med Phys 2024; 25:e14415. [PMID: 38924344 PMCID: PMC11492423 DOI: 10.1002/acm2.14415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/25/2024] [Accepted: 05/06/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND Intracranial stereotactic radiosurgery (SRS) aims at achieving highly conformal dose distribution and, at the same time, attaining rapid dose falloff outside the treatment target. SRS is performed using different techniques including dynamic conformal arcs (DCA) and volumetric modulated arc therapy (VMAT). PURPOSE In this study, we compare dose conformity and falloff in DCA and VMAT plans for SRS with a single target. METHODS To compare dose conformity in SRS plans, we employ a novel conformity indexC I d e x p $C{I}_{{d}_{exp}}$ , RTOG conformity index (C I R T O G $C{I}_{RTOG}$ ), and Riet-Paddick conformity index (C I R P $C{I}_{RP}$ ). In addition, we use indicesR 50 % $R50\% $ ,V 10 G y ${V}_{10Gy}$ , andV 12 G y ${V}_{12Gy}$ to evaluate dose falloff. For each of the considered 118 cases of SRS, two plans were created using DCA and VMAT. A two-tailed Student's t-test was used to evaluate the difference between the employed indices for the DCA and VMAT plans. RESULTS The studied VMAT plans were characterized by higher dose conformity than the DCA plans. The differences between the conformity indices for the DCA plans and VMAT plans were statistically significant. The DCA plans had a smaller number of monitor units (MUs) and smaller indices R50%, V10 Gy, and V12 Gy than the VMAT plans. However, the differences between R50%, V10 Gy, and V12 Gy for the DCA and VMAT plans were not statistically significant. CONCLUSIONS Although the studied VMAT plans had higher dose conformity, they also had larger MUs than the DCA plans. In terms of dose falloff characterized by parameters R50%, V10 Gy, and V12 Gy, DCA serves as a reasonable alternative to VMAT in the case of a single brain metastasis.
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Affiliation(s)
| | - Yücel Altundal
- Florida Cancer Specialists & Research InstituteHudsonFloridaUSA
| | - Sunil Kandel
- Florida Cancer Specialists & Research InstituteHudsonFloridaUSA
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Mukwada G, Chamunyonga C, Rowshanfarzad P, Gill S, Ebert MA. Insights into the dosimetric and geometric characteristics of stereotactic radiosurgery for multiple brain metastases: A systematic review. PLoS One 2024; 19:e0307088. [PMID: 39121064 PMCID: PMC11315342 DOI: 10.1371/journal.pone.0307088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Accepted: 06/30/2024] [Indexed: 08/11/2024] Open
Abstract
BACKGROUND GammaKnife (GK) and CyberKnife (CK) have been the mainstay stereotactic radiosurgery (SRS) solution for multiple brain metastases (MBM) for several years. Recent technological advancement has seen an increase in single-isocentre C-arm linac-based SRS. This systematic review focuses on dosimetric and geometric insights into contemporary MBM SRS and thereby establish if linac-based SRS has matured to match the mainstay SRS delivery systems. METHODS The PubMed, Web of Science and Scopus databases were interrogated which yielded 891 relevant articles that narrowed to 20 articles after removing duplicates and applying the inclusion and exclusion criteria. Primary studies which reported the use of SRS for treatment of MBM SRS and reported the technical aspects including dosimetry were included. The review was limited to English language publications from January 2015 to August 2023. Only full-length papers were included in the final analysis. Opinion papers, commentary pieces, letters to the editor, abstracts, conference proceedings and editorials were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. The reporting of conformity indices (CI) and gradient indices, V12Gy, monitor units and the impact of translational and rotational shifts were extracted and analysed. RESULTS The single-isocentre technique for MBM dominated recent SRS studies and the most studied delivery platforms were Varian. The C-arm linac-based SRS plan quality and normal brain tissue sparing was comparable to GK and CK and in some cases better. The most used nominal beam energy was 6FFF, and optimised couch and collimator angles could reduce mean normal brain dose by 11.3%. Reduction in volume of the healthy brain receiving a certain dose was dependent on the number and size of the metastases and the relative geometric location. GK and CK required 4.5-8.4 times treatment time compared with linac-based SRS. Rotational shifts caused larger changes in CI in C-arm linac-based single-isocentre SRS. CONCLUSION C-arm linac-based SRS produced comparable MBM plan quality and the delivery is notably shorter compared to GK and CK SRS.
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Affiliation(s)
- Godfrey Mukwada
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Western Australia, Australia
- School of Physics, Mathematics and Computing, University of Western Australia, Crawley, Western Australia, Australia
| | - Crispen Chamunyonga
- School of Clinical Sciences, Discipline of Radiation Therapy, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Pejman Rowshanfarzad
- School of Physics, Mathematics and Computing, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Advanced Technologies in Cancer Research (CATCR), Perth, Western Australia, Australia
| | - Suki Gill
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Western Australia, Australia
- School of Physics, Mathematics and Computing, University of Western Australia, Crawley, Western Australia, Australia
| | - Martin A. Ebert
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Hospital Ave, Nedlands, Western Australia, Australia
- School of Physics, Mathematics and Computing, University of Western Australia, Crawley, Western Australia, Australia
- Centre for Advanced Technologies in Cancer Research (CATCR), Perth, Western Australia, Australia
- School of Medicine and Population Health, University of Wisconsin, Madison, Wisconsin, United States of America
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ES Fodil N, Abdelhakem MM, Yahia GA, Ammar H. Evaluation of Dynamic Multi-Leaf Collimator (MLC) versus Fixed MLC for Intensity Modulated Radiotherapy (IMRT) Using the Agility 160-Leaf Collimator. Asian Pac J Cancer Prev 2024; 25:2467-2474. [PMID: 39068581 PMCID: PMC11480600 DOI: 10.31557/apjcp.2024.25.7.2467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Indexed: 07/30/2024] Open
Abstract
AIM This study aimed to evaluate the efficacy of static or step-and-shoot intensity-modulated radiotherapy (ssIMRT) and dynamic intensity-modulated radiotherapy (dIMRT) delivery techniques for various treatment sites. MATERIALS AND METHODS The treatment planning system (TPS) was utilized to develop optimal treatment plans for twenty-seven patients selected for this comparative study, including nine with head and neck cancer, nine with prostate cancer, and nine with cervical cancer. The prescribed doses were 7000cGy/33fr, 7425cGy/33fr, and 5000cGy/25fr for the nasopharynx, prostate, and cervix cases, respectively, in both ssIMRT and dIMRT delivery techniques. Plans were generated using the Monaco treatment planning system with a 6MV photon beam and nine equidistant fields. Plan evaluation criteria included dose-volume histogram analysis, dose homogeneity index, conformity index, radiation delivery time, and monitor unit requirements. RESULTS All plans were optimized to ensure that 98% of the planning target volume (PTV) received at least 95% of the prescribed dose, while meeting the planning objectives for organs at risk. dIMRT plans exhibited superior conformity (CI = 0.85 ± 0.05) compared to ssIMRT plans (CI = 0.79 ± 0.08), with statistically significant differences (P < 0.01). Inhomogeneity within the PTV was significantly higher in ssIMRT plans (HI = 0.10 ± 0.02) compared to dIMRT plans (HI = 0.09 ± 0.01), with a significant difference (P < 0.01). Delivery time per fraction was significantly lower in dIMRT compared to ssIMRT (P < 0.01). Furthermore, dIMRT plans required a higher mean monitor unit value (1335.4 ± 172.2) compared to ssIMRT plans (974.4 ± 133.6) with a significant difference (P < 0.001). CONCLUSION The findings of this study indicate that dIMRT provides improved target coverage, homogeneity, and conformity while reducing treatment delivery time compared to ssIMRT.
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Affiliation(s)
- Nabila ES Fodil
- Radiotherapy Department, National Cancer Institute, Shefaa Alorman Hospital, Egypt.
| | - Mohamed M Abdelhakem
- Radiotherapy Department, National Cancer Institute, Shefaa Alorman Hospital, Egypt.
| | - Gamal A Yahia
- Department of Physics, Faculty of Science, Aswan University, Egypt.
| | - Hani Ammar
- Department of Radiotherapy, Children’s Cancer Hospital, Egypt.
- Clinical Oncology Department, Faculty of Medicine, Aswan University, Egypt.
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Singh R, Robert N, Madan R, Kumar N, Tewari MK, Dhandapani S, Sahoo SK. Analysis of the treatment planning metrics and their correlation with morphology of intracranial lesions in Gamma Knife stereotactic radiosurgery. J Cancer Res Ther 2024; 20:949-958. [PMID: 39023603 DOI: 10.4103/jcrt.jcrt_36_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 04/28/2024] [Indexed: 07/20/2024]
Abstract
BACKGROUND Gamma Knife Radiosurgery (GKRS) has established a role in treating various benign brain pathologies. The radiosurgery planning necessitates a proper understanding of radiation dose distribution in relation to the target lesion and surrounding eloquent area. The quality of a radiosurgery plan is determined by various planning parameters. Here, we have reviewed various GKRS planning parameters and analyzed their correlation with the morphology of treated brain lesions. METHOD A total of 430 treatment plans (71 meningioma, 133 vestibular schwannoma/VS, 150 arteriovenous malformation/AVM, 76 pituitary adenoma/PA treated with GKRS between December 2013 and May 2023) were analyzed for target coverage (TC), conformity index (CI), homogeneity index (HI), and gradient index (GI). RESULT The values of CIPaddick and CILomax for PA were lower and differed significantly from meningioma, VS, and AVM. The value of HI for PA was higher and differed significantly when compared with meningioma, VS, and AVM. The values of HI for AVM were also significantly higher than VS and meningioma. The mean GI was 3.02, 2.92, 3.03, and 2.88 for meningioma, VS, AVM, and PA, respectively. The value of GI for meningioma and AVM was significantly higher when compared with the values for VS and PA. The mean TC was 0.94 for meningioma, 0.96 for VS, 0.95 for AVM, and 0.90 for PA. The value TC of PA was lower and differed significantly when compared with VS, AVM, and meningioma. Lesions with a volume of ≤1 cc had poor planning metrics as the spillage of radiation may be higher. CONCLUSION The GKRS planning parameters depend on the size, shape, nature, and location of intracranial lesions. Therefore, each treatment plan needs to be evaluated thoroughly and a long-term follow-up is needed to establish their relation with clinical outcome.
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Affiliation(s)
- Ranjit Singh
- Department of Radiotherapy, PGIMER, Chandigarh, India
| | | | - Renu Madan
- Department of Radiotherapy, PGIMER, Chandigarh, India
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Kuperman VY, Altundal Y, Kouskoulas TN. Toward an improved assessment of dose conformity in radiotherapy. Med Phys 2024; 51:2210-2220. [PMID: 37947447 DOI: 10.1002/mp.16775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Evaluation of dose conformity is important to ensure minimum dose to normal tissue and sufficient dose coverage of the planning target volume (PTV). The existing conformity indices depend on the PTV volume and do not differentiate between two different scenarios: overdosing normal tissue and underdosing PTV. PURPOSE In this study, we introduce a novel index to assess conformity of dose distributions in radiotherapy. METHODS The suggested conformity indexC I d e x p $C{I_{{d_{exp}}}}$ is defined by the ratio of the volume representing actual "non-conformity" of the planned dose and the volume representing acceptable "non-conformity." The latter volume is produced by expanding the PTV. If both the average distance (d ¯ $\overline d $ ) between the reference isodose surface and planning target volume and arbitrarily selected PTV expansion margin (d e x p ${d_{exp}}$ ) are much smaller than the size of the PTV,C I d e x p $C{I_{{d_{exp}}}}$ approximately equals the ratiod ¯ d e x p $\dfrac{{\bar d}}{{{d_{exp}}}}$ . In this work,C I d e x p $C{I_{{d_{exp}}}}$ was utilized to analyze 90 cases of brain metastases treated with stereotactic radiation therapy (SRS) and 102 cases of lung cancer treated with stereotactic body radiation therapy (SBRT). RESULTS Ford e x p ${d_{exp}}$ = 0.1 cm, all considered SRS treatment plans were characterized byC I d e x p < 1 $C{I_{{d_{exp}}}} < 1$ while 2 out of 102 SBRT plans hadC I d e x p > 1 $C{I_{{d_{exp}}}} > 1$ . The average values ofC I d e x p $C{I_{{d_{exp}}}}$ for SRS and SBRT plans were 0.31 and 0.43, respectively. Ford e x p ${d_{exp}}$ = 0.2 cm, all studied treatment plans hadC I d e x p < 1 $C{I_{{d_{exp}}}} < 1$ , and the average values ofC I d e x p $C{I_{{d_{exp}}}}$ for SRS and SBRT plans were 0.15 and 0.25, respectively. CONCLUSIONS The suggested conformity indexC I d e x p $C{I_{{d_{exp}}}}$ varies less with PTV volume than the RTOG and Riet-Paddick indices frequently used for evaluation of dose conformity. In addition,C I d e x p $C{I_{{d_{exp}}}}$ can be expressed as a sum of two terms which describe "over-coverage" and "under-coverage" of the treatment target. The results confirm thatC I d e x p $C{I_{{d_{exp}}}}$ can be used for evaluation of dose conformity in SRS and SBRT.
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Affiliation(s)
- Vadim Y Kuperman
- Florida Cancer Specialists & Research Institute, Hudson, Florida, USA
| | - Yücel Altundal
- Florida Cancer Specialists & Research Institute, Hudson, Florida, USA
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Spaniol M, Abo-Madyan Y, Ruder AM, Fleckenstein J, Giordano FA, Stieler F. Homogenous dose prescription in Gamma Knife Radiotherapy: Combining the best of both worlds. Phys Med 2024; 117:103202. [PMID: 38159546 DOI: 10.1016/j.ejmp.2023.103202] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/28/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024] Open
Abstract
PURPOSE Stereotactic radiosurgery with linear accelerators (LINACs) or Leksell Gamma Knife® (LGK, Elekta AB) is an established treatment option for intracranial tumors. When those are involving/abutting organs at risk (OAR), homogenous and normofractionated treatments outmatch single fraction deliveries. In such situations, it would be desirable to balance LINAC's homogeneity benefits with LGK's dose gradient attributes. In this study, we determined homogeneity and OAR sparing ranges using a non-clinical, homogenous prototype version of LGK Lightning. METHODS We retrospectively analyzed thirty fractionated LGK Icon in-house patients with acoustic neuromas, pituitary adenomas and meningiomas. Four treatment plans were generated (54 Gy,1.8 Gy/fx) per patient: one LINAC plan, one clinical Lightning plan ("LGK") and two prototype Lightning plans ("LGK Hom" and "LGK OAR"). We analyzed Dmean and D2% for different OAR, Gradient Index (GI), Paddick Conformity Index (PCI), Homogeneity Index (HI) and beam-on-time (BOT). RESULTS While the LINAC vs. Lightning plans (LGK Hom|LGK OAR|LGK) boast better homogeneity (median: 1.08 vs. 1.18|1.24|1.35) and shorter BOT (median: 137 s vs. 432 s|510 s|510 s), Lightning plans show improved GI (median: 6.68 vs. 3.86|3.50|3.19), similar PCI (median: 0.75 vs. 0.76|0.75|0.82) and significantly reduced OAR doses. For in-tumor OAR, LGK Hom and LINAC plans achieves similar OAR sparing with improved GI for LGK Hom. CONCLUSIONS This study is a preliminary attempt to combine the dosimetric advantages of LINAC and LGK treatment planning. We observed that LGK plan homogeneity can be improved toward LINAC standards while maintaining the LGK advantage of favorable OAR doses and GI. Additionally, in-tumor OAR hotspots can be considerably reduced.
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Affiliation(s)
- Manon Spaniol
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| | - Yasser Abo-Madyan
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| | - Arne M Ruder
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| | - Jens Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| | - Frank A Giordano
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
| | - Florian Stieler
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Germany, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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Murali V. Proposal of a New Conformal Factor and Normal Tissue Penalty Factor for Radiosurgery Treatments. Cureus 2023; 15:e44800. [PMID: 37809184 PMCID: PMC10558895 DOI: 10.7759/cureus.44800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2023] [Indexed: 10/10/2023] Open
Abstract
The quality of a treatment plan is evaluated by the conformality of the prescribed isodose around the target and the homogeneity of dose distribution inside the target. Presently, to check the target volume conformality, a number of published conformity indices are in use. Most of these indices are based on the target volume coverage by prescribed isodose, with respect to the total volume of the target. Some take into account the normal tissue covered by the prescribed isodose and suitably weigh the target coverage to evaluate conformity. In this study, for the irradiation of normal tissue by the prescription isodose, a normal tissue penalty factor is proposed and for the target conformality, a new conformal factor is proposed by applying this normal tissue penalty factor to the target coverage. The proposed conformal factor is evaluated for a few sample analytical cases and the results are compared with those obtained using the published conformity indices.
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Qingya P, Yizhong F, Fuke Z, Shengjie L, Linzhao T, Yuling L. STANDARD-DEVIATION BASED CONFORMITY INDEX FOR EVALUATING TREATMENT PLAN OF INTENSITY MODULATED RADIOTHERAPY IN LUNG CANCER. RADIATION PROTECTION DOSIMETRY 2023; 199:87-94. [PMID: 36420536 DOI: 10.1093/rpd/ncac228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 09/13/2022] [Accepted: 10/15/2022] [Indexed: 06/16/2023]
Abstract
This paper attempts to find a new conformity index (CI) calculation method with slice and angle information for evaluating lung cancer radiation treatment plan. A total of 20 lung cancer patients in 2016-2019 were selected. Treatment plans were made for each patient. Parameters used in the process of making treatment plans were set the same. The CI and the standard-deviation based CI (SDCI) that contains angle and slice information were calculated. Comparison of results calculated with SDCI and CI were made. The results of the two methods for the patients showed the same trend. Different shapes of simulated dose distribution line shows SDCI can provide more detail information about the target area. Special shapes of simulated dose distribution line for SDCI showed inaccuracy in angle information. The parameter SDCI has more advantage towards the traditional CI for it can provide angle and slice information. However, more angles need to be calculated.
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Affiliation(s)
- Pan Qingya
- Department of Chemo-Radiotherapy Oncology, QingHe Center Hospital, 80 SanYang Road, Qinghe, 054800 HeBei, China
| | - Fan Yizhong
- Department of Chemo-Radiotherapy Oncology, QingHe Center Hospital, 80 SanYang Road, Qinghe, 054800 HeBei, China
| | - Zhang Fuke
- Department of Chemo-Radiotherapy Oncology, QingHe Center Hospital, 80 SanYang Road, Qinghe, 054800 HeBei, China
| | - Luan Shengjie
- Department of Chemo-Radiotherapy Oncology, QingHe Center Hospital, 80 SanYang Road, Qinghe, 054800 HeBei, China
| | - Tian Linzhao
- Department of Chemo-Radiotherapy Oncology, QingHe Center Hospital, 80 SanYang Road, Qinghe, 054800 HeBei, China
| | - Lv Yuling
- Department of Chemo-Radiotherapy Oncology, QingHe Center Hospital, 80 SanYang Road, Qinghe, 054800 HeBei, China
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Baroudi H, Brock KK, Cao W, Chen X, Chung C, Court LE, El Basha MD, Farhat M, Gay S, Gronberg MP, Gupta AC, Hernandez S, Huang K, Jaffray DA, Lim R, Marquez B, Nealon K, Netherton TJ, Nguyen CM, Reber B, Rhee DJ, Salazar RM, Shanker MD, Sjogreen C, Woodland M, Yang J, Yu C, Zhao Y. Automated Contouring and Planning in Radiation Therapy: What Is 'Clinically Acceptable'? Diagnostics (Basel) 2023; 13:667. [PMID: 36832155 PMCID: PMC9955359 DOI: 10.3390/diagnostics13040667] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 01/21/2023] [Accepted: 01/30/2023] [Indexed: 02/12/2023] Open
Abstract
Developers and users of artificial-intelligence-based tools for automatic contouring and treatment planning in radiotherapy are expected to assess clinical acceptability of these tools. However, what is 'clinical acceptability'? Quantitative and qualitative approaches have been used to assess this ill-defined concept, all of which have advantages and disadvantages or limitations. The approach chosen may depend on the goal of the study as well as on available resources. In this paper, we discuss various aspects of 'clinical acceptability' and how they can move us toward a standard for defining clinical acceptability of new autocontouring and planning tools.
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Affiliation(s)
- Hana Baroudi
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Kristy K. Brock
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Department of Imaging Physics, Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Wenhua Cao
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Xinru Chen
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Caroline Chung
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Laurence E. Court
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mohammad D. El Basha
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Maguy Farhat
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Skylar Gay
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Mary P. Gronberg
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Aashish Chandra Gupta
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Department of Imaging Physics, Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Soleil Hernandez
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Kai Huang
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - David A. Jaffray
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Department of Imaging Physics, Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Rebecca Lim
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Barbara Marquez
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Kelly Nealon
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Tucker J. Netherton
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Callistus M. Nguyen
- Department of Imaging Physics, Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Brandon Reber
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
- Department of Imaging Physics, Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Dong Joo Rhee
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ramon M. Salazar
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Mihir D. Shanker
- The University of Queensland, Saint Lucia 4072, Australia
- The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Carlos Sjogreen
- Department of Physics, University of Houston, Houston, TX 77004, USA
| | - McKell Woodland
- Department of Imaging Physics, Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Department of Computer Science, Rice University, Houston, TX 77005, USA
| | - Jinzhong Yang
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Cenji Yu
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Yao Zhao
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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10
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Kuperman VY, Altundal Y. Novel approach for the evaluation of dose conformity in radiotherapy. Med Phys 2023; 50:1086-1095. [PMID: 36272439 DOI: 10.1002/mp.15998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 12/14/2022] Open
Abstract
PURPOSE We describe a new approach to evaluate conformity of dose distributions in radiotherapy. METHODS The suggested conformity factor λ is defined by using existing conformity indices and expansion of the planning target volume (PTV). If the average distance ( d ¯ $\bar d$ ) between the PTV and reference isodose surface and an arbitrarily selected PTV expansion margin ( d e x p ${d_{exp}}$ ) are both much smaller than the size of the PTV, then λ approximately equals the ratio d ¯ d e x p $\frac{{\bar d}}{{{d_{exp}}}}$ . We use λ to analyze several cases of stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). RESULTS In the case of SRS with a single target or multiple targets, treatment plans produced with the help of volumetric modulated arc therapy (VMAT) have smaller λ than plans produced by using dynamic conformal arcs (DCA). Likewise, it is demonstrated that in the case of SBRT, λ is reduced by employing VMAT instead of DCA. It is also shown that if the distance between the reference isodose surface and surface of the PTV is fixed, λ varies less with variations in PTV volume compared to frequently used conformity indices. CONCLUSIONS The described conformity factor λ can be applied clinically to compare and rank treatment plans for lesions of different sizes. It is suggested that conditions λ < 1 $\lambda < 1$ and λ > 1 can be employed as "pass" and "fail" criteria, respectively, for dose conformity assessment with appropriate choice of d e x p ${d_{exp}}$ .
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Affiliation(s)
- Vadim Y Kuperman
- Florida Cancer Specialists & Research Institute, Hudson, Florida, USA
| | - Yücel Altundal
- Florida Cancer Specialists & Research Institute, Hudson, Florida, USA
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11
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Sümer E, Tek E, Türe OA, Şengöz M, Dinçer A, Özcan A, Pamir MN, Özduman K, Ozturk-Isik E. The effect of tumor shape irregularity on Gamma Knife treatment plan quality and treatment outcome: an analysis of 234 vestibular schwannomas. Sci Rep 2022; 12:21809. [PMID: 36528740 PMCID: PMC9759589 DOI: 10.1038/s41598-022-25422-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
The primary aim of Gamma Knife (GK) radiosurgery is to deliver high-dose radiation precisely to a target while conforming to the target shape. In this study, the effects of tumor shape irregularity (TSI) on GK dose-plan quality and treatment outcomes were analyzed in 234 vestibular schwannomas. TSI was quantified using seven different metrics including volumetric index of sphericity (VioS). GK treatment plans were created on a single GK-Perfexion/ICON platform. The plan quality was measured using selectivity index (SI), gradient index (GI), Paddick's conformity index (PCI), and efficiency index (EI). Correlation and linear regression analyses were conducted between shape irregularity features and dose plan indices. Machine learning was employed to identify the shape feature that predicted dose plan quality most effectively. The treatment outcome analysis including tumor growth control and serviceable hearing preservation at 2 years, were conducted using Cox regression analyses. All TSI features correlated significantly with the dose plan indices (P < 0.0012). With increasing tumor volume, vestibular schwannomas became more spherical (P < 0.05) and the dose plan indices varied significantly between tumor volume subgroups (P < 0.001 and P < 0.01). VioS was the most effective predictor of GK indices (P < 0.001) and we obtained 89.36% accuracy (79.17% sensitivity and 100% specificity) for predicting PCI. Our results indicated that TSI had significant effects on the plan quality however did not adversely affect treatment outcomes.
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Affiliation(s)
- Esra Sümer
- grid.11220.300000 0001 2253 9056Institute of Biomedical Engineering, Boğaziçi University, Kandilli Campus, Rasathane Cad, 34684 Üsküdar, Istanbul Turkey
| | - Ece Tek
- grid.411117.30000 0004 0369 7552Department of Radiation Oncology, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - O. Artunç Türe
- grid.411117.30000 0004 0369 7552Department of Radiation Oncology, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Meriç Şengöz
- grid.411117.30000 0004 0369 7552Department of Neurosurgery, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Alp Dinçer
- grid.411117.30000 0004 0369 7552Department of Radiology, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Alpay Özcan
- grid.11220.300000 0001 2253 9056Department of Electrical and Electronics Engineering, Boğaziçi University, Istanbul, Turkey
| | - M. Necmettin Pamir
- grid.411117.30000 0004 0369 7552Department of Neurosurgery, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Koray Özduman
- grid.411117.30000 0004 0369 7552Department of Neurosurgery, School of Medicine, Acıbadem Mehmet Ali Aydınlar University, Istanbul, Turkey
| | - Esin Ozturk-Isik
- grid.11220.300000 0001 2253 9056Institute of Biomedical Engineering, Boğaziçi University, Kandilli Campus, Rasathane Cad, 34684 Üsküdar, Istanbul Turkey
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Mørkeset ST, Lervåg C, Lund JÅ, Jensen C. Clinical experience of volumetric-modulated flattening filter free stereotactic body radiation therapy of lesions in the lung with deep inspiration breath-hold. J Appl Clin Med Phys 2022; 23:e13733. [PMID: 35867387 PMCID: PMC9512343 DOI: 10.1002/acm2.13733] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 05/19/2022] [Accepted: 06/23/2022] [Indexed: 11/05/2022] Open
Abstract
This clinical study aimed to evaluate lung cancer patients' ability to perform deep inspiration breath-hold (DIBH) during CT simulation and throughout the treatment course of stereotactic body radiation therapy (SBRT). In addition, target sizes, organ at risk (OAR) sizes, and doses to the respective volumes in filter-free volumetric-modulated arc therapy plans performed under free-breathing (FB) and DIBH conditions were evaluated. Twenty-one patients with peripheral lesions were included, of which 13 were eligible for SBRT. All patients underwent training for breath-hold during CT, and if they complied with the requirements, two CT scans were obtained: CT scan in DIBH and a four-dimensional CT scan in FB. The treatment plans in FB and DIBH were generated, and the dose parameters and volume sizes were compared. The endpoints for evaluation were patient compliance, target dose coverage, and doses to the OARs. This clinical study showed high patient DIBH compliance during both CT simulation and treatment for patients with lung cancer. A significant reduction in target volumes was achieved with SBRT in DIBH, in addition to significantly decreased doses to the heart, chest wall, and lungs. DIBH in SBRT of lung lesions is feasible, and a routine to manage intra-fractional deviation should be established upon implementation.
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Affiliation(s)
- Siri T Mørkeset
- Department of Oncology and Rehabilitation, Møre and Romsdal Hospital Trust, Ålesund Hospital, Ålesund, Norway
| | - Christoffer Lervåg
- Department of Oncology and Rehabilitation, Møre and Romsdal Hospital Trust, Ålesund Hospital, Ålesund, Norway
| | - Jo-Åsmund Lund
- Department of Oncology and Rehabilitation, Møre and Romsdal Hospital Trust, Ålesund Hospital, Ålesund, Norway.,Department of Health Sciences in Ålesund, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Ålesund, Norway
| | - Christer Jensen
- Department of Health Sciences in Ålesund, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Ålesund, Norway.,Department of Medicine and Healthcare, Møre and Romsdal Hospital Trust, Ålesund Hospital, Ålesund, Norway
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Jayaprakash S, Pendse A, Deshpande S. Significance of Dosimetric Parameters in Patients Undergoing Gamma Knife Radiosurgery for Vestibular Schwannoma. J Med Phys 2022; 47:206-211. [PMID: 36212199 PMCID: PMC9543002 DOI: 10.4103/jmp.jmp_5_22] [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] [Received: 01/22/2022] [Revised: 03/16/2022] [Accepted: 04/06/2022] [Indexed: 11/15/2022] Open
Abstract
Vestibular schwannoma (VS) is a benign, encapsulated, and slow-growing tumor of the myelin-forming cells of the 8th cranial nerve. Gamma Knife radiosurgery (GKRS) has become a widely accepted primary treatment modality for small- to medium-sized VSs. In the case of VS, highly conformal, precisely focused radiation is delivered to the acoustic tumor in a single session under the direct supervision of a radiosurgery team
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Kaplan LP, Korreman SS. A systematically compiled set of quantitative metrics to describe spatial characteristics of radiotherapy dose distributions and aid in treatment planning. Phys Med 2021; 90:164-175. [PMID: 34673370 DOI: 10.1016/j.ejmp.2021.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Many quantitative metrics have been proposed in literature for characterization of spatial dose properties. The aim of this study is to work towards much-needed consensus in the radiotherapy community on which of these metrics to use. We do this by comparing characteristics of the metrics and providing a systematically selected set of metrics to comprehensively quantify properties of the spatial dose distribution. METHODS We searched the literature for metrics to quantitatively evaluate dose conformity, homogeneity, gradient (overall and directional), and distribution and location of over- and under-dosed sub-volumes. For each spatial dose property, we compared the responses of its corresponding metrics to simulated dose variations in a virtual water phantom. Selection criteria were a metric's ability to describe simulated scenarios robustly and to be visualized in an intuitive way. RESULTS We saw substantial differences in the responses of metrics to the simulated dose variations. Some conformity and homogeneity metrics were unable to quantify certain types of changes (e.g. target under-coverage). Others showed a large dependency on the shape and volume of targets and isodoses. Metric values differed between calculations in a static plan and in simulated full treatment courses including setup errors, especially for metrics quantifying distribution and location of hot and cold spots. We provide an Eclipse plugin script to calculate and visualize selected metrics. CONCLUSION The selected set of metrics provides complementary and comprehensive quantitative information about the spatial dose distribution. This work serves as a step towards broader consensus on the use of spatial dose metrics.
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Affiliation(s)
- Laura Patricia Kaplan
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark.
| | - Stine Sofia Korreman
- Department of Oncology, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
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Hypofractionated Stereotactic Radiotherapy for the Treatment of Benign Intracranial Meningiomas: Long-Term Safety and Efficacy. ACTA ACUST UNITED AC 2021; 28:3683-3691. [PMID: 34590613 PMCID: PMC8482200 DOI: 10.3390/curroncol28050314] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 11/29/2022]
Abstract
Introduction: Hypofractionated stereotactic radiotherapy (hSRT) has emerged as an alternative to single-fraction stereotactic radiosurgery (SRS) and conventionally fractionated radiotherapy for the treatment of intracranial meningiomas (ICMs). However, there is a need for data showing long-term efficacy and complication rates, particularly for larger tumors in sensitive locations. Methods: A retrospective review was conducted on adult patients with ICMs seen at a tertiary care center. Eligible patients were treated with the CyberKnife platform and had a planned treatment course of 3–5 fractions from 2011–2020. The local control was assessed based on radiographic stability and the late toxicity/radionecrosis rates were recorded. Radiographic progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method. Results: In total, 62 patients (age 26–87) with 67 treated tumors were included in this study with a median follow-up of 64.7 months. RT was delivered as the primary treatment in 62.7% of cases and for recurrence in 37.3%. The most common tumor locations were the convexity of the brain and the base of the skull. The tumor sizes ranged from 0.1–51.8 cc and the median planning target volume was 4.9 cc. The most common treatment schedule was 18 Gy in 3 fractions. The five-year PFS and OS were 85.2% and 91.0%, respectively. The late grade III/IV toxicity rate was 3.2% and the radionecrosis rate was 4.8%. Conclusions: Based on our data, hSRT remains an effective modality to treat low-grade ICMs with acceptable long-term toxicity and radionecrosis rates. hSRT should be offered to patients who are not ideal candidates for SRS while preserving the benefits of hypofractionation.
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16
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Patel G, Mandal A, Choudhary S, Mishra R, Shende R. Plan evaluation indices: A journey of evolution. Rep Pract Oncol Radiother 2020; 25:336-344. [PMID: 32210739 PMCID: PMC7082629 DOI: 10.1016/j.rpor.2020.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/07/2020] [Accepted: 03/02/2020] [Indexed: 12/27/2022] Open
Abstract
AIM A systemic review and analysis of evolution journey of indices, such as conformity index (CI), homogeneity index (HI) and gradient index (GI), described in the literature. BACKGROUND Modern radiotherapy techniques like VMAT, SRS and SBRT produce highly conformal plans and provide better critical structure and normal tissue sparing. These treatment techniques can generate a number of competitive plans for the same patients with different dose distributions. Therefore, indices like CI, HI and GI serve as complementary tools in addition to visual slice by slice isodose verification while plan evaluation. Reliability and accuracy of these indices have been tested in the past and found shortcomings and benefits when compared to one another. MATERIAL AND METHODS Potentially relevant studies published after 1993 were identified through a pubmed and web of science search using words "conformity index", "Homogeneity index", "Gradient index"," Stereotactic radiosurgery"," stereotactic Body radiotherapy" "complexity metrics" and "plan evaluation index". Combinations of words "plan evaluation index conformity index" were also searched as were bibliographies of downloaded papers. RESULTS AND CONCLUSIONS Mathematical definitions of plan evaluation indices modified with time. CI definitions presented by various authors tested at their own and could not be generalized. Those mathematical definitions of CI which take into account OAR sparing grant more confidence in plan evaluation. Gradient index emerged as a significant plan evaluation index in addition to CI whereas homogeneity index losing its credibility. Biological index base plan evaluation is becoming popular and may replace or alter the role of dosimetrical indices.
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Affiliation(s)
- Ganeshkumar Patel
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Abhijit Mandal
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Sunil Choudhary
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ritusha Mishra
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ravindra Shende
- Department of Radiotherapy, Balco Medical Center, New Raipur, Sector 36, Raipur, Chattisgarh 493661, India
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Cao T, Dai Z, Ding Z, Li W, Quan H. Analysis of different evaluation indexes for prostate stereotactic body radiation therapy plans: conformity index, homogeneity index and gradient index. PRECISION RADIATION ONCOLOGY 2019. [DOI: 10.1002/pro6.1072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Affiliation(s)
- Tingting Cao
- School of Physics and TechnologyWuhan University Wuhan China
- Tongji Hospital, Tongji Medical CollegeHuazhong University of Science and Technology Wuhan China
| | - Zhitao Dai
- School of Physics and TechnologyWuhan University Wuhan China
- Cancer Hospital Chinese Academy of Medical SciencesShenzhen Center Shenzhen China
| | - Zhen Ding
- Cancer Hospital Chinese Academy of Medical SciencesShenzhen Center Shenzhen China
| | - Wuzhou Li
- School of Physics and TechnologyWuhan University Wuhan China
| | - Hong Quan
- School of Physics and TechnologyWuhan University Wuhan China
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18
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Long-Term Tumor Control Rates Following Gamma Knife Radiosurgery for Acoustic Neuroma. World Neurosurg 2019; 122:366-371. [DOI: 10.1016/j.wneu.2018.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 10/31/2018] [Accepted: 11/02/2018] [Indexed: 11/19/2022]
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Sung K, Choi YE. Dose gradient curve: A new tool for evaluating dose gradient. PLoS One 2018; 13:e0196664. [PMID: 29698471 PMCID: PMC5919624 DOI: 10.1371/journal.pone.0196664] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 04/17/2018] [Indexed: 11/18/2022] Open
Abstract
Purpose Stereotactic radiotherapy, which delivers an ablative high radiation dose to a target volume for maximum local tumor control, requires a rapid dose fall-off outside the target volume to prevent extensive damage to nearby normal tissue. Currently, there is no tool to comprehensively evaluate the dose gradient near the target volume. We propose the dose gradient curve (DGC) as a new tool to evaluate the quality of a treatment plan with respect to the dose fall-off characteristics. Methods The average distance between two isodose surfaces was represented by the dose gradient index (DGI) estimated by a simple equation using the volume and surface area of isodose levels. The surface area was calculated by mesh generation and surface triangulation. The DGC was defined as a plot of the DGI of each dose interval as a function of the dose. Two types of DGCs, differential and cumulative, were generated. The performance of the DGC was evaluated using stereotactic radiosurgery plans for virtual targets. Results Over the range of dose distributions, the dose gradient of each dose interval was well-characterized by the DGC in an easily understandable graph format. Significant changes in the DGC were observed reflecting the differences in planning situations and various prescription doses. Conclusions The DGC is a rational method for visualizing the dose gradient as the average distance between two isodose surfaces; the shorter the distance, the steeper the dose gradient. By combining the DGC with the dose-volume histogram (DVH) in a single plot, the DGC can be utilized to evaluate not only the dose gradient but also the target coverage in routine clinical practice.
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Affiliation(s)
- KiHoon Sung
- Department of Radiation Oncology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Republic of Korea
| | - Young Eun Choi
- Department of Radiation Oncology, Gachon University Gil Medical Center, Gachon University School of Medicine, Incheon, Republic of Korea
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Dyer BA, Jenshus A, Mayadev JS. Integrated skin flash planning technique for intensity-modulated radiation therapy for vulvar cancer prevents marginal misses and improves superficial dose coverage. Med Dosim 2018; 44:7-10. [PMID: 29500108 DOI: 10.1016/j.meddos.2018.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/22/2018] [Accepted: 01/25/2018] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Radiation therapy (RT) plays a definitive role in locally advanced vulvar cancer, and in the adjuvant setting with high risk postoperative features after wide local excision. There is significant morbidity associated with traditional, large RT fields using 2D or 3D techniques, and the use of intensity-modulated radiation therapy (IMRT) in vulvar cancer is increasing. However, there remains a paucity of technical information regarding the prevention of a marginal miss during the treatment planning process. The use of an integrated skin flash (ISF) during RT planning can be used to account for anatomic variation, and intra- and interfraction motion seen during treatment. CASE DESCRIPTION Herein we present the case of a patient with a T1aN0M0, Stage IA vulva cancer to illustrate the progressive vulvar swelling and lymph edema seen during treatment and retrospectively evaluate the dosimetric effects of using an ISF RT plan vs standard RT planning techniques. CONCLUSIONS Standard planning techniques to treat vulvar cancer patients with IMRT do not sufficiently account for the change in patient anatomy and can lead to a marginal miss. ISF is an RT planning technique that can decrease the risk of a marginal miss and the technique is easily implemented during the planning stages of RT treatment. Furthermore, use of an ISF technique can improve vulvar clinical target volume coverage and plan homogeneity. Based on our experience, and this study, a 2-cm ISF is suggested to account for variations in daily clinical setup and changes in patient anatomy during treatment.
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Affiliation(s)
- Brandon A Dyer
- Department of Radiation Oncology, University of California Davis, Sacramento, CA
| | - Abriel Jenshus
- Department of Radiation Oncology, University of California Davis, Sacramento, CA
| | - Jyoti S Mayadev
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA.
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Menon SV, Paramu R, Bhasi S, Nair RK. Evaluation of Plan Quality Metrics in Stereotactic Radiosurgery/Radiotherapy in the Treatment Plans of Arteriovenous Malformations. J Med Phys 2018; 43:214-220. [PMID: 30636846 PMCID: PMC6299748 DOI: 10.4103/jmp.jmp_25_18] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Aim: Several plan quality metrics are available for the evaluation of stereotactic radiosurgery/radiotherapy plans. This is a retrospective analysis of 60 clinical treatment plans of arteriovenous malformation (AVM) patients to study clinical usefulness of selected plan quality metrics. Materials and Methods: The treatment coverage parameters Radiation Therapy Oncology Group (RTOG) Conformity Index (CIRTOG), RTOG Quality of Coverage (QRTOG), RTOG Homogeneity Index (HIRTOG), Lomax Conformity Index (CILomax), Paddick's Conformity Index (CIPaddick), and dose gradient parameters Paddick's Gradient Index (GIPaddick) and Equivalent Fall-off Distance (EFOD) were calculated for the cohort of patients. Before analyzing patient plans, the influence of calculation grid size on selected plan quality metrics was studied on spherical targets. Results: It was found that the plan quality metrics are independent of calculation grid size ≤2 mm. EFOD was found to increase linearly with increase in target volume, and a linear fit equation was obtained. Conclusions: The analysis shows that RTOG indices and EFOD would suffice for routine clinical radiosurgical treatment plan evaluation if a dose distribution is available for visual inspection.
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Affiliation(s)
| | - Raghukumar Paramu
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - Saju Bhasi
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
| | - Raghuram Kesavan Nair
- Division of Radiation Physics, Regional Cancer Centre, Thiruvananthapuram, Kerala, India
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22
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Tseng CL, Eppinga W, Seravalli E, Hackett S, Brand E, Ruschin M, Lee YK, Atenafu EG, Sahgal A. Dosimetric feasibility of the hybrid Magnetic Resonance Imaging (MRI)-linac System (MRL) for brain metastases: The impact of the magnetic field. Radiother Oncol 2017; 125:273-279. [PMID: 29079310 DOI: 10.1016/j.radonc.2017.09.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 09/24/2017] [Accepted: 09/28/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND PURPOSE We aimed to investigate the suitability of treating patients with single brain metastases using stereotactic radiosurgery (SRS) with the MRL and to characterize the dosimetric impact at tissue-air interfaces resulting primarily from the electron return effect (ERE). MATERIAL AND METHODS 24 patients treated for intact single brain metastases were analyzed. Three radiotherapy plans with the same prescribed dose were generated for each case: (1) noncoplanar volumetric modulated arc therapy (VMAT), (2) coplanar step-and-shoot intensity modulated radiotherapy (IMRT) on the MRL in the absence (MRLB=0), and (3) in the presence of the transverse magnetic field (MRLB=1.5). The plans were evaluated using cumulative dose-volume histograms and by calculation of Paddick conformity index (CI), V100%, V12Gy minus gross tumor volume (V12Gy - GTV), and V2Gy. At tissue-air boundaries, the dosimetric impact of the magnetic field was quantified using a 5 mm rim of tissue. RESULTS All plans met the target coverage and organs-at-risk planning objectives. Differences between all investigated dosimetric parameters significantly favored the VMAT plans as compared to the MRLB=0 and MRLB=1.5 plans, except for V2Gy. The mean V12Gy - GTV and V2Gy marginally favored the MRLB=0 plans compared to the MRLB=1.5 plans (mean difference: 0.45 cm3, p = 0.0019 and 16.46 cm3, p < 0.0001, respectively). The presence of the magnetic field resulted in a statistically significant but small increase in mean dose and D2cc in the skin (0.08 Gy, p < 0.0001 and 0.6 Gy, p < 0.0001, respectively) and around air cavities (0.07 Gy, p = 0.0092 and 0.3 Gy, p = 0.0004, respectively). CONCLUSIONS It is feasible to generate stereotactic radiation plans that satisfy clinical requirements using the MRL in the setting of single brain metastases. The dosimetric impact of the magnetic field including the ERE at tissue-air boundaries is minor and does not negatively impact target conformity or dose gradient.
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Affiliation(s)
- Chia-Lin Tseng
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada.
| | - Wietse Eppinga
- Department of Radiotherapy, University Medical Center Utrecht, The Netherlands
| | - Enrica Seravalli
- Department of Radiotherapy, University Medical Center Utrecht, The Netherlands
| | - Sara Hackett
- Department of Radiotherapy, University Medical Center Utrecht, The Netherlands
| | - Eric Brand
- Department of Radiotherapy, University Medical Center Utrecht, The Netherlands
| | - Mark Ruschin
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - Young K Lee
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - Eshetu G Atenafu
- Department of Biostatistics, University Health Network, University of Toronto, Toronto, Canada
| | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
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Iridium-Knife: Another knife in radiation oncology. Brachytherapy 2017; 16:884-892. [PMID: 28392144 DOI: 10.1016/j.brachy.2017.03.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 02/19/2017] [Accepted: 03/07/2017] [Indexed: 01/30/2023]
Abstract
PURPOSE Intratarget dose escalation with superior conformity is a defining feature of three-dimensional (3D) iridium-192 (192Ir) high-dose-rate (HDR) brachytherapy (BRT). In this study, we analyzed the dosimetric characteristics of interstitial 192Ir HDR BRT for intrathoracic and cerebral malignancies. We examined the dose gradient sharpness of HDR BRT compared with that of linear accelerator-based stereotactic radiosurgery and stereotactic body radiation therapy, usually called X-Knife, to demonstrate that it may as well be called a Knife. METHODS AND MATERIALS Treatment plans for 10 patients with recurrent glioblastoma multiforme or intrathoracic malignancies, five of each entity, treated with X-Knife (stereotactic radiosurgery for glioblastoma multiforme and stereotactic body radiation therapy for intrathoracic malignancies) were replanned for simulated HDR BRT. For 3D BRT planning, we used identical structure sets and dose prescription as for the X-Knife planning. The indices for qualitative treatment plan analysis encompassed planning target volume coverage, conformity, dose falloff gradient, and the maximum dose-volume limits to different organs at risk. RESULTS Volume coverage in HDR plans was comparable to that calculated for X-Knife plans with no statistically significant difference in terms of conformity. The dose falloff gradient-sharpness-of the HDR plans was considerably steeper compared with the X-Knife plans. CONCLUSIONS Both 3D 192Ir HDR BRT and X-Knife are effective means for intratarget dose escalation with HDR BRT achieving at least equal conformity and a steeper dose falloff at the target volume margin. In this sense, it can reasonably be argued that 3D 192Ir HDR BRT deserves also to be called a Knife, namely Iridium-Knife.
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Ventura T, Lopes MDC, Ferreira BC, Khouri L. SPIDERplan: A tool to support decision-making in radiation therapy treatment plan assessment. Rep Pract Oncol Radiother 2016; 21:508-516. [PMID: 27698591 DOI: 10.1016/j.rpor.2016.07.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 04/06/2016] [Accepted: 07/03/2016] [Indexed: 11/17/2022] Open
Abstract
AIM In this work, a graphical method for radiotherapy treatment plan assessment and comparison, named SPIDERplan, is proposed. It aims to support plan approval allowing independent and consistent comparisons of different treatment techniques, algorithms or treatment planning systems. BACKGROUND Optimized plans from modern radiotherapy are not easy to evaluate and compare because of their inherent multicriterial nature. The clinical decision on the best treatment plan is mostly based on subjective options. MATERIALS AND METHODS SPIDERplan combines a graphical analysis with a scoring index. Customized radar plots based on the categorization of structures into groups and on the determination of individual structures scores are generated. To each group and structure, an angular amplitude is assigned expressing the clinical importance defined by the radiation oncologist. Completing the graphical evaluation, a global plan score, based on the structures score and their clinical weights, is determined. After a necessary clinical validation of the group weights, SPIDERplan efficacy, to compare and rank different plans, was tested through a planning exercise where plans had been generated for a nasal cavity case using different treatment planning systems. RESULTS SPIDERplan method was applied to the dose metrics achieved by the nasal cavity test plans. The generated diagrams and scores successfully ranked the plans according to the prescribed dose objectives and constraints and the radiation oncologist priorities, after a necessary clinical validation process. CONCLUSIONS SPIDERplan enables a fast and consistent evaluation of plan quality considering all targets and organs at risk.
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Affiliation(s)
- Tiago Ventura
- Physics Department of University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Medical Physics Department, Instituto Português de Oncologia de Coimbra Francisco Gentil, EPE, Avenida Bissaya Barreto, n° 98, 3000-075 Coimbra, Portugal; Institute for Systems Engineering and Computers at Coimbra, Coimbra, Portugal
| | - Maria do Carmo Lopes
- Physics Department of University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Medical Physics Department, Instituto Português de Oncologia de Coimbra Francisco Gentil, EPE, Avenida Bissaya Barreto, n° 98, 3000-075 Coimbra, Portugal; Institute for Systems Engineering and Computers at Coimbra, Coimbra, Portugal
| | - Brigida Costa Ferreira
- School of Allied Health Technologies Polytechnic Institute of Porto, Rua Valente Perfeito, 322 4400-330 Vila Nova de Gaia, Portugal; Institute for Systems Engineering and Computers at Coimbra, Coimbra, Portugal
| | - Leila Khouri
- Radiotherapy Department of Instituto Português de Oncologia de Coimbra Francisco Gentil, EPE, Avenida Bissaya Barreto, n° 98, 3000-075 Coimbra, Portugal
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Li K. Aperture effect for LINAC-based SRS in small target treatment†. JOURNAL OF RADIOSURGERY AND SBRT 2016; 4:21-29. [PMID: 29296423 PMCID: PMC5658831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 06/08/2015] [Indexed: 06/07/2023]
Abstract
PURPOSE Stereotactic Radiosurgery (SRS) can utilize different techniques. For small target SRS, the selections of the apertures of cone or MLC field influence the treatment significantly. In this study, while the aperture of the MLC and cone field vary, the dosimetric characteristics of the two techniques are compared for SRS of small targets which are in the favor of magnifying the dosimetric effect. METHODS AND MATERIALS An anthropomorphic phantom was used to simulate the patient with an arbitrary drawn cranial target, whose volume is equivalent to a 4 millimeter sphere. Single 360 ARC plans were generated with Eclipse external beam and cone based treatment planning system from Varian Medical System. For MLC based plan, the apertures fit to the structure with circle margins varying with 2mm, 3mm, 4mm, 5mm and 6mm. These setups were compared with the cones being selected to be 5mm, 10mm, 12mm, 14mm and 16mm in diameter. For the MLC based plan, the leaf-edge-contour meet points were selected to be in the middle. Jaw positions were used both recommend and optimize options, which are provided by the treatment planning system. Mean dose was treated as the prescription dose. Comparison of the two planning techniques was carried out using 12Gy Volume (V12Gy) from dose-volume histogram (DVH), maximum dose to the prescription dose ratio (MDPD), ratio PITV (PIV/TV), radiation conformity index (RCI), which is defined to be TVPIV/PIV, and an integrated conformity index (TVPIV2/ (TVxPIV)), where PIV is the prescription isodose surface volume, TV is target volume, and TVPIV is the intersection of TV and the PIV. RESULTS For the apertures used for this study, while MLC and cone based plans were compared by prescribed at 20Gy, the V12Gy ranges were from 1.0cc to 5.3cc with average at 3.3cc, and 0.1cc to 3.2cc with average value at 1.5cc. The variations of MDPD were 9% with average value at 1.04, and 12% with average at 1.03. The varying ranges of PITV were 35% with average value at 0.80, and 17% with average value at 0.54. Integrated conformity index (ICI) variations were up to 45% with average value at 0.34, and at the level of the 7% with average value at 0.42. CONCLUSIONS For small target SRS, there are larger variations in V12Gy, PITV, and ICI in MLC based plan than those of cone based plan, while the difference is not significant for MDPD in both settings at the selected aperture sizes. These information could help in decision making through sensitivity study while sufficient clinical outcome information were available. The multiple ARC treatment plan and the clinical reality of algorithm for small aperture also need further investigation.
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Affiliation(s)
- Kaile Li
- John R Marsh Cancer Center, Hagerstown, MD 21742, USA
- Associates in Medical Physics, Greenbelt, MD 20706, USA
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Alfonso JCL, Herrero MA, Núñez L. A dose-volume histogram based decision-support system for dosimetric comparison of radiotherapy treatment plans. Radiat Oncol 2015; 10:263. [PMID: 26715096 PMCID: PMC4696205 DOI: 10.1186/s13014-015-0569-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 12/08/2015] [Indexed: 12/05/2022] Open
Abstract
Background The choice of any radiotherapy treatment plan is usually made after the evaluation of a few preliminary isodose distributions obtained from different beam configurations. Despite considerable advances in planning techniques, such final decision remains a challenging task that would greatly benefit from efficient and reliable assessment tools. Methods For any dosimetric plan considered, data on dose-volume histograms supplied by treatment planning systems are used to provide estimates on planning target coverage as well as on sparing of organs at risk and the remaining healthy tissue. These partial metrics are then combined into a dose distribution index (DDI), which provides a unified, easy-to-read score for each competing radiotherapy plan. To assess the performance of the proposed scoring system, DDI figures for fifty brain cancer patients were retrospectively evaluated. Patients were divided in three groups depending on tumor location and malignancy. For each patient, three tentative plans were designed and recorded during planning, one of which was eventually selected for treatment. We thus were able to compare the plans with better DDI scores and those actually delivered. Results When planning target coverage and organs at risk sparing are considered as equally important, the tentative plan with the highest DDI score is shown to coincide with that actually delivered in 32 of the 50 patients considered. In 15 (respectively 3) of the remaining 18 cases, the plan with highest DDI value still coincides with that actually selected, provided that organs at risk sparing is given higher priority (respectively, lower priority) than target coverage. Conclusions DDI provides a straightforward and non-subjective tool for dosimetric comparison of tentative radiotherapy plans. In particular, DDI readily quantifies differences among competing plans with similar-looking dose-volume histograms and can be easily implemented for any tumor type and localization, irrespective of the planning system and irradiation technique considered. Moreover, DDI permits to estimate the dosimetry impact of different priorities being assigned to sparing of organs at risk or to better target coverage.
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Affiliation(s)
- J C L Alfonso
- Center for Information Services and High Performance Computing (ZIH), Technische Universität Dresden, Nöthnitzer Str. 46, Dresden, 01062, Germany.
| | - M A Herrero
- Department of Applied Mathematics, Faculty of Mathematical Sciences, Universidad Complutense de Madrid (UCM), Ciudad Universitaria, Plaza Ciencias 3, Madrid, 28040, Spain.
| | - L Núñez
- Radiophysics Department, Hospital Universitario Puerta de Hierro (HUPH), Calle Manuel de Falla 1 Majadahonda, Madrid, 28222, Spain.
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Mansouri A, Larjani S, Klironomos G, Laperriere N, Cusimano M, Gentili F, Schwartz M, Zadeh G. Predictors of response to Gamma Knife radiosurgery for intracranial meningiomas. J Neurosurg 2015; 123:1294-300. [DOI: 10.3171/2014.12.jns141687] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT
In this paper, the authors’ aim was to determine short-term volumetric and diametric tumor growth and identify clinical, radiological, and dosimetric predictors of adverse radiation events (AREs) following stereotactic radiosurgery (SRS) for intracranial WHO Grade I meningiomas.
METHODS
This is a retrospective review of all WHO Grade I meningiomas that were treated with SRS (primary or adjuvant) between December 2005 and June 2012 at the University Health Network. Seventy-five patients had at least 24 months of both clinical and radiological follow-up and were, therefore, included in this study. Tumor growth was defined as any volumetric or diametric change greater than 10% per year. Any variation less than +10% was considered growth stability. Volumetric measurements were made using T1-weighted gadolinium-enhanced 3-T MRI scans and ITK-SNAP software. Tumor growth rates were calculated using the specific growth rate (SGR). Univariate statistics were used to identify predictors of post-SRS AREs. All statistical analyses were performed using IBM SPSS.
RESULTS
Women accounted for 69.3% of patients, and the mean treatment age was 58.6 years. Median follow-up was 36.2 months. Twenty-one (28%) patients had undergone prior resection. Two (3%) patients required salvage surgical intervention following SRS. The majority of the lesions (56%) were skull base tumors. Median tumor volume and diameter were 5.2 cm3 and 27.5 mm, respectively. The absence of tumor growth was observed in 39 cases (52%) based on the volumetric measurements, while the absence of tumor growth was observed in 69 cases (92%) based on the diametric measurements. Twenty-six patients (34.6%) experienced new-onset AREs, including headache (17.3%), cranial neuropathy (10.6%), speech impairment (2.7%), tremors (2.7%), and ataxia (1.3%). Fourteen patients (18.7%) experienced new-onset edema, and 4 of these patients were symptomatic. A lower conformity index (1.24 vs 1.4) was significantly associated with the development of edema (p < 0.001 power > 0.8). Patients with meningiomas that had growth rates of more than 10% per year were more likely to experience long-term headaches after SRS (p = 0.022).
CONCLUSIONS
Volume-based reporting of SRS outcomes for meningiomas may be a more accurate method given the complex morphology of some lesions. The conformity index was identified as a predictor of edema following radiosurgery.
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Affiliation(s)
- Alireza Mansouri
- 1Division of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto
| | - Soroush Larjani
- 1Division of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto
| | - George Klironomos
- 1Division of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto
- 2Division of Neurosurgery, University of Toronto
| | - Normand Laperriere
- 3Department of Radiation Oncology, Princess Margaret Cancer Centre/University Health Network, University of Toronto
| | - Michael Cusimano
- 2Division of Neurosurgery, University of Toronto
- 4Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto; and
| | - Fred Gentili
- 1Division of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto
- 2Division of Neurosurgery, University of Toronto
| | - Michael Schwartz
- 2Division of Neurosurgery, University of Toronto
- 5Department of Surgery (Neurosurgery), Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada
| | - Gelareh Zadeh
- 1Division of Neurosurgery, Toronto Western Hospital, University Health Network, Toronto
- 2Division of Neurosurgery, University of Toronto
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Denton TR, Shields LBE, Howe JN, Spalding AC. Quantifying isocenter measurements to establish clinically meaningful thresholds. J Appl Clin Med Phys 2015; 16:5183. [PMID: 26103187 PMCID: PMC5690087 DOI: 10.1120/jacmp.v16i2.5183] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/23/2014] [Accepted: 11/23/2014] [Indexed: 11/23/2022] Open
Abstract
A dataset range of isocenter congruency verification tests have been examined from a statistical perspective for the purpose of establishing tolerance levels that are meaningful, based on the fundamental limitation of linear accelerator isocentricity and the demands of a high-precision stereotactic radiosurgery program. Using a laser-defined isocenter, a total of 149 individual isocenter congruency tests were examined with recorded values for ideal spatial corrections to the isocenter test tool. These spatial corrections were determined from radiation exposures recorded on an electronic portal imaging device (EPID) at various gantry, collimator, and treatment couch combinations. The limitations of establishing an ideal isocenter were quantified from each variable which contributed to uncertainty in isocenter definition. Individual contributors to uncertainty, specifically, daily positioning setup errors, gantry sag, multileaf collimator (MLC) offset, and couch walkout, were isolated from isocenter congruency measurements to determine a clinically meaningful isocenter measurement. Variations in positioning of the test tool constituted, on average, 0.38 mm magnitude of correction. Gantry sag and MLC offset contributed 0.4 and 0.16 mm, respectively. Couch walkout had an average degrading effect to isocenter of 0.72 mm. Considering the magnitude of uncertainty contributed by each uncertainty variable and the nature of their combination, an appropriate schedule action and immediate action level were determined for use in analyzing daily isocenter congruency test results in a stereotactic radiosurgery (SRS) program. The recommendations of this study for this linear accelerator include a schedule action level of 1.25 mm and an immediate action level of 1.50mm, requiring prompt correction response from clinical medical physicists before SRS or stereotactic body radiosurgery (SBRT) is administered. These absolute values were derived from considering relative data from a specific linear accelerator and, therefore, represent a means by which a numerical quantity can be used as a test threshold with relative specificity to a particular linear accelerator.
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Affiliation(s)
- Travis R Denton
- The Norton Cancer Institute Radiation Center, Louisville, KY and Associates in Medical Physics, LLC, Greenbelt, MD.
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Park JM, Park SY, Ye SJ, Kim JH, Carlson J, Wu HG. New conformity indices based on the calculation of distances between the target volume and the volume of reference isodose. Br J Radiol 2014; 87:20140342. [PMID: 25225915 DOI: 10.1259/bjr.20140342] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To present conformity indices (CIs) based on the distance differences between the target volume (TV) and the volume of reference isodose (VRI). METHODS The points on the three-dimensional surfaces of the TV and the VRI were generated. Then, the averaged distances between the points on the TV and the VRI were calculated (CIdistance). The performance of the presented CIs were evaluated by analysing six situations, which were a perfect match, an expansion and a reduction of the distance from the centroid to the VRI compared with the distance from the centroid to the TV by 10%, a lateral shift of the VRI by 3 cm, a rotation of the VRI by 45° and a spherical-shaped VRI having the same volume as the TV. The presented CIs were applied to the clinical prostate and head and neck (H&N) plans. RESULTS For the perfect match, CIdistance was 0 with 0 as the standard deviation (SD). When expanding and reducing, CIdistance was 10 and -10 with SDs <1.3, respectively. With shifting and rotating of the VRI, the CIdistance was almost 0 with SDs >11. The average value of the CIdistance in the prostate and H&N plans was 0.13 ± 7.44 and 6.04 ± 23.27, respectively. CONCLUSION The performance of the CIdistance was equal or better than those of the conventional CIs. ADVANCES IN KNOWLEDGE The evaluation of target conformity by the distances between the surface of the TV and the VRI could be more accurate than evaluation with volume information.
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Affiliation(s)
- J M Park
- 1 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea
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Burghelea M, Verellen D, Gevaert T, Depuydt T, Poels K, Simon V, De Ridder M. Feasibility of using the Vero SBRT system for intracranial SRS. J Appl Clin Med Phys 2014; 15:4437. [PMID: 24423838 PMCID: PMC5711224 DOI: 10.1120/jacmp.v15i1.4437] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 09/25/2013] [Accepted: 08/30/2013] [Indexed: 11/23/2022] Open
Abstract
The Vero SBRT system was benchmarked in a planning study against the Novalis SRS system for quality of delivered dose distributions to intracranial lesions and assessing the Vero system's capacity for SRS. A total of 27 patients with one brain lesion treated on the Novalis system, with 3 mm leaf width MLC and C‐arm gantry, were replanned for Vero, with a 5 mm leaf width MLC mounted on an O‐ring gantry allowing rotations around both the horizontal and vertical axis. The Novalis dynamic conformal arc (DCA) planning included vertex arcs, using 90° couch rotation. These vertex arcs cannot be reproduced with Vero due to the mechanical limitations of the O‐ring gantry. Alternative class solutions were investigated for the Vero. Additionally, to distinguish between the effect of MLC leaf width and different beam arrangements on dose distributions, the Vero class solutions were also applied for Novalis. In addition, the added value of noncoplanar IMRT was investigated in this study. Quality of the achieved dose distributions was expressed in the conformity index (CI) and gradient index (GI), and compared using a paired Student's t‐test with statistical significance for p‐values ≤0.05. For lesions larger than 5 cm3, no statistical significant difference in conformity was observed between Vero and Novalis, but for smaller lesions, the dose distributions showed a significantly better conformity for the Novalis (ΔCI=13.74%, p=0.0002) mainly due to the smaller MLC leaf width. Using IMRT on Vero reduces this conformity difference to nonsignificant levels. The cutoff for achieving a GI around 3, characterizing a sharp dose falloff outside the target volume was 4 cm3 for Novalis and 7 cm3 for Vero using DCA technique. Using noncoplanar IMRT, this threshold was reduced to 3 cm3 for the Vero system. The smaller MLC and the presence of the vertex fields allow the Novalis system to better conform the dose around the lesion and to obtain steeper dose falloff outside the lesion. Comparable dosimetric characteristics can be achieved with Vero for lesions larger than 3 cm3 and using IMRT. PACS number: 87.55.D
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Kataria T, Sharma K, Subramani V, Karrthick KP, Bisht SS. Homogeneity Index: An objective tool for assessment of conformal radiation treatments. J Med Phys 2013; 37:207-13. [PMID: 23293452 PMCID: PMC3532749 DOI: 10.4103/0971-6203.103606] [Citation(s) in RCA: 232] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 07/01/2012] [Accepted: 07/17/2012] [Indexed: 01/06/2023] Open
Abstract
Homogeneity Index (HI) is an objective tool to analyz the uniformity of dose distribution in the target volume. Various formulae have been described in literature for its calculation but there is paucity of data regarding the ideal formula and the factors affecting this index. This study was undertaken to analyze HI in our patients using various formulae and to find out the co-relation between HI and prescribed dose, target volume and target location. A retrospective review of 99 patients was performed. HI was calculated using five different formulae (A-E). The patients were divided in five groups each, based on prescribed dose, target volume and target location and mean HI of each group was analysed to find the co-relation between these factors and HI. When there were multiple target volumes the primary target volume was studied. The statistical calculation was done using SPSS version 16.0. Ninety nine patients were found evaluable with 75 males and 24 females. Ninety five patients were treated with radical intent and four with palliative intent. The sites treated were head and neck (46.4%), Pelvis (17.1%), brain (15.1%), abdomen (12.1%), and thorax (6.1%). The mean prescribed dose was 4304 cGy (centiGray) and the mean target volume was 476.2 cc. The mean value of HI was 1.21, 2.08, 30.13, 21.51 and 1.27 with different formulae. There was considerable agreement between HI calculated using various formulae specially the formulae considering prescribed dose (C, D). On statistical analysis, there was no significant co-relation between the location and volume of target but there was a trend toward better HI with increasing prescribed dose. Future studies with more number of patients can confirm our results.
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Affiliation(s)
- Tejinder Kataria
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta- The Medicity, Sector- 38, Gurgaon, Haryana, India
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Effect of smoothing on treatment plan efficiency in IMRT: eclipse Helios™ dose optimisation. JOURNAL OF RADIOTHERAPY IN PRACTICE 2012. [DOI: 10.1017/s1460396911000367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractBackground and purpose: This study examined the effect of varying the X–Y smoothing values on the average Leaf Pair Opening (LPO), MUFactor and total number of monitor units (MU) in a cohort of 20 prostate and head and neck (H&N) patients treated with dynamic intensity-modulated radiotherapy (IMRT).Material and methods: Plans were created using Varian Eclipse™ Treatment Planning System (TPS) version 8.9.09 (Varian Medical Systems, Palo Alto, CA). Clinically approved and dosimetrically verified plans were used as a reference plans. These were re-optimised varying the X and Y smoothing parameters from 0 to 100 in various combinations.Results: For the prostate patients, at X = 0 and Y = 0, the average LPO was 2.4 cm (σ = 0.20 cm) and 3.5 cm (σ = 0.35 cm) for X = 100 and Y = 100. For H&N, the LPO averaged over all fields increased from 1.7 cm (σ = 0.17 cm) at X = 0 and Y = 0 to 2.3 cm (σ = 0.27 cm) at X = 100 and Y = 90. The MUFactor decreased from 1.81 (σ = 0.19) at X = 0 and Y = 0 to 1.38 (σ = 0.11) at X = 100 and Y = 100 for prostates and from 1.50 (σ = 0.14) at X = 0 and Y = 0 to 1.24 (σ = 0.09) for X = 100 and Y = 90 for H&N. Total MU for prostates decreased from 1028.0 (σ = 244.6) at X = 0 and Y = 0 to 688.4 (σ = 159.3) at X = 100 and Y = 100 and from 913 (σ = 267.2) at X = 0 and Y = 0 to 696 (σ = 214.03) at X = 100 and Y = 90 for H&N.Conclusions: Increasing smoothing decreases MUFactor, decreases total MU and increases average LPO but does not greatly enhance organs at risk (OAR) sparing. The Homogeneity Index (HI) and Paddick Conformity Index (CIPAD) appear to vary little after increasing smoothing up to approximately X = 80 and Y = 70.
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Craniospinal Irradiation Techniques: A Dosimetric Comparison of Proton Beams With Standard and Advanced Photon Radiotherapy. Int J Radiat Oncol Biol Phys 2011; 81:637-46. [DOI: 10.1016/j.ijrobp.2010.06.039] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 06/14/2010] [Accepted: 06/18/2010] [Indexed: 11/24/2022]
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Stanley J, Breitman K, Dunscombe P, Spencer DP, Lau H. Evaluation of stereotactic radiosurgery conformity indices for 170 target volumes in patients with brain metastases. J Appl Clin Med Phys 2011; 12:3449. [PMID: 21587193 PMCID: PMC5718686 DOI: 10.1120/jacmp.v12i2.3449] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/15/2010] [Accepted: 01/04/2011] [Indexed: 01/23/2023] Open
Abstract
A database of clinically approved stereotactic radiosurgery treatment plans was created. One hundred and seventy targets in the database were then retrospectively evaluated using conformity indices suggested by RTOG, SALT‐Lomax and Paddick. Relationships between the three alternative conformity indices were determined. The Paddick index combines the information provided by the RTOG and SALT‐Lomax indices into a single index. The variation in the geometric overlap ratio, which is related to the SALT‐Lomax index, was found to be not clinically relevant for our cohort of patients, and thus the Paddick and RTOG indices can be directly related. It was found that access to a dose volume histogram or dose distribution for a treatment plan renders the RTOG conformity index sufficient for plan quality evaluation. PACS number: 87.53.Ly
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Affiliation(s)
- Julia Stanley
- Department of Medical Physics, Tom Baker Cancer Center, Calgary, AB T2N 4N2, Canada.
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Dhabaan A, Elder E, Schreibmann E, Crocker I, Curran WJ, Oyesiku NM, Shu HK, Fox T. Dosimetric performance of the new high-definition multileaf collimator for intracranial stereotactic radiosurgery. J Appl Clin Med Phys 2010; 11:3040. [PMID: 20717077 PMCID: PMC5720445 DOI: 10.1120/jacmp.v11i3.3040] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 10/22/2009] [Accepted: 02/08/2010] [Indexed: 11/23/2022] Open
Abstract
The objective was to evaluate the performance of a high-definition multileaf collimator (MLC) of 2.5 mm leaf width (MLC2.5) and compare to standard 5 mm leaf width MLC (MLC5) for the treatment of intracranial lesions using dynamic conformal arcs (DCA) technique with a dedicated radiosurgery linear accelerator. Simulated cases of spherical targets were created to study solely the effect of target volume size on the performance of the two MLC systems independent of target shape complexity. In addition, 43 patients previously treated for intracranial lesions in our institution were retrospectively planned using DCA technique with MLC2.5 and MLC5 systems. The gross tumor volume ranged from 0.07 to 40.57 cm3 with an average volume of 5.9 cm3. All treatment parameters were kept the same for both MLC-based plans. The plan evaluation was performed using figures of merits (FOM) for a rapid and objective assessment on the quality of the two treatment plans for MLC2.5 and MLC5. The prescription isodose surface was selected as the greatest isodose surface covering >or= 95% of the target volume and delivering 95% of the prescription dose to 99% of target volume. A Conformity Index (CI) and conformity distance index (CDI) were used to quantifying the dose conformity to a target volume. To assess normal tissue sparing, a normal tissue difference (NTD) was defined as the difference between the volume of normal tissue receiving a certain dose utilizing MLC5 and the volume receiving the same dose using MLC2.5. The CI and normal tissue sparing for the simulated spherical targets were better with the MLC2.5 as compared to MLC5. For the clinical patients, the CI and CDI results indicated that the MLC2.5 provides better treatment conformity than MLC5 even at large target volumes. The CI's range was 1.15 to 2.44 with a median of 1.59 for MLC2.5 compared to 1.60-2.85 with a median of 1.71 for MLC5. Improved normal tissue sparing was also observed for MLC2.5 over MLC5, with the NTD always positive, indicating improvement, and ranging from 0.1 to 8.3 for normal tissue receiving 50% (NTV50), 70% (NTV70) and 90% (NTV90) of the prescription dose. The MLC2.5 has a dosimetric advantage over the MLC5 in Linac-based radiosurgery using DCA method for intracranial lesions, both in treatment conformity and normal tissue sparing when target shape complexity increases.
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Affiliation(s)
- Anees Dhabaan
- Emory University, Department of Radiation Oncology, Atlanta, GA 30322, USA.
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