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Jr JTL, Wilson LJ, Oliveira C, Braunstein SE, Faught AM. A Survey of Submission and Review Standards across Clinical Radiation Oncology and Medical Physics Journals: Devising the Optimal Criteria for Reproducibility and Sustained Impact. Int J Radiat Oncol Biol Phys 2023; 117:e528-e529. [PMID: 37785641 DOI: 10.1016/j.ijrobp.2023.06.1807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
PURPOSE/OBJECTIVE(S) Publishing and editorial policies differ substantially across the Radiation Oncology (RO) and Medical Physics (MedPhys) compendium of journals. Adoptance of modern standards in scientific publishing and data sharing have the potential to improve the impact and reliability of the RO literature. MATERIALS/METHODS We characterized the editorial, authorship and peer reviewer policies of various prominent clinical RO (N = 16) and medical physics (N = 9) peer-reviewed journals affiliated with professional societies for characteristics that are associated with improved reproducibility and rigorous review. A combination of tools including Enhancing the QUAlity and Transparency Of health Research (EQUATOR), Findability, Accessibility, Interoperability, and Reuse (FAIR), and Quality Output Checklist and Content Assessment (QuOCCA) principles were used to quantify the value and reproducibility of journal policies. Cohen's kappa coefficient was utilized to assess agreement between reviewers. Components of the above tools were regressed against various scientometric indices (H-index, IF, etc.) to identify factors that are associated with perceived relative importance within the field. RESULTS Reviewer agreement (κ) for scientometric indices was highest (1.0) for criteria for statistical review and data submission standards and lowest (-0.246) for various submission checklists. Data availability statements were endorsed (44%) or required (31%) in a higher proportion of RO journals relative to MedPhys journals (44%, 0% respectively). Data repository submission was required in <10% of journals. FAIR adoptance was poor (31%, 22%) in RO and MedPhys journals. ≥1 EQUATOR guideline checklist was endorsed or required in 76% of journals. While there were no glaring differences in editorial policies between RO and MedPhys journals, there was substantial heterogeneity of scientometrics evaluating the rigor of data submission, reproducibility standards, and statistical review criteria. Linear regression of journal impact factors indicated a predictive relationship between FAIR adoption standards, use of EQUATOR checklists, and more rigorous statistical method submission criteria. CONCLUSION The present review documented and confirmed significant variation in submission, review, and publication policies across RO and MedPhys journals. Established scientometric standards, FAIR principle adoptance, and more rigorous statistical methodology were predictive of increasing journal impact factor.
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Affiliation(s)
- J T Lucas Jr
- St. Jude Children's Research Hospital, Memphis, TN
| | - L J Wilson
- St. Jude Children's Research Hospital, Memphis, TN
| | - C Oliveira
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN
| | - S E Braunstein
- University of California San Francisco, Department of Radiation Oncology, San Francisco, CA
| | - A M Faught
- St. Jude Children's Research Hospital, Memphis, TN
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Hernandez S, Burger H, Nguyen C, Paulino AC, Lucas JT, Faught AM, Duryea J, Netherton T, Rhee DJ, Cardenas C, Howell R, Fuentes D, Pollard-Larkin J, Court L, Parkes J. Validation of an automated contouring and treatment planning tool for pediatric craniospinal radiation therapy. Front Oncol 2023; 13:1221792. [PMID: 37810961 PMCID: PMC10556471 DOI: 10.3389/fonc.2023.1221792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 09/06/2023] [Indexed: 10/10/2023] Open
Abstract
Purpose Treatment planning for craniospinal irradiation (CSI) is complex and time-consuming, especially for resource-constrained centers. To alleviate demanding workflows, we successfully automated the pediatric CSI planning pipeline in previous work. In this work, we validated our CSI autosegmentation and autoplanning tool on a large dataset from St. Jude Children's Research Hospital. Methods Sixty-three CSI patient CT scans were involved in the study. Pre-planning scripts were used to automatically verify anatomical compatibility with the autoplanning tool. The autoplanning pipeline generated 15 contours and a composite CSI treatment plan for each of the compatible test patients (n=51). Plan quality was evaluated quantitatively with target coverage and dose to normal tissue metrics and qualitatively with physician review, using a 5-point Likert scale. Three pediatric radiation oncologists from 3 institutions reviewed and scored 15 contours and a corresponding composite CSI plan for the final 51 test patients. One patient was scored by 3 physicians, resulting in 53 plans scored total. Results The algorithm automatically detected 12 incompatible patients due to insufficient junction spacing or head tilt and removed them from the study. Of the 795 autosegmented contours reviewed, 97% were scored as clinically acceptable, with 92% requiring no edits. Of the 53 plans scored, all 51 brain dose distributions were scored as clinically acceptable. For the spine dose distributions, 92%, 100%, and 68% of single, extended, and multiple-field cases, respectively, were scored as clinically acceptable. In all cases (major or minor edits), the physicians noted that they would rather edit the autoplan than create a new plan. Conclusions We successfully validated an autoplanning pipeline on 51 patients from another institution, indicating that our algorithm is robust in its adjustment to differing patient populations. We automatically generated 15 contours and a comprehensive CSI treatment plan for each patient without physician intervention, indicating the potential for increased treatment planning efficiency and global access to high-quality radiation therapy.
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Affiliation(s)
- Soleil Hernandez
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, United States
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Hester Burger
- Department Medical Physics, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
| | - Callistus Nguyen
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Arnold C. Paulino
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - John T. Lucas
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Austin M. Faught
- Department of Radiation Oncology, St. Jude Children’s Research Hospital, Memphis, TN, United States
| | - Jack Duryea
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Tucker Netherton
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Dong Joo Rhee
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Carlos Cardenas
- Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Rebecca Howell
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, United States
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - David Fuentes
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Julianne Pollard-Larkin
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, United States
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Laurence Court
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, United States
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Jeannette Parkes
- Department of Radiation Oncology, Groote Schuur Hospital and University of Cape Town, Cape Town, South Africa
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Gutkin PM, Skinner L, Jiang A, Donaldson SS, Loo BW, Oh J, Wang YP, von Eyben R, Snyder J, Bredfeldt JS, Breneman JC, Constine LS, Faught AM, Haas-Kogan D, Holmes JA, Krasin M, Larkin C, Marcus KJ, Maxim PG, McClelland S, Murphy B, Palmer JD, Perkins SM, Shen CJ, Terezakis S, Bush K, Hiniker SM. Feasibility of the Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) System for Anesthesia Avoidance in Pediatric Patients: A Multicenter Trial. Int J Radiat Oncol Biol Phys 2023; 117:96-104. [PMID: 37001762 DOI: 10.1016/j.ijrobp.2023.03.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/12/2023] [Accepted: 03/22/2023] [Indexed: 05/11/2023]
Abstract
PURPOSE The Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) system was the first published radiation therapy (RT)-compatible system to reduce the need for pediatric anesthesia through video-based distraction. We evaluated the feasibility of AVATAR implementation and effects on anesthesia use, quality of life, and anxiety in a multicenter pediatric trial. METHODS AND MATERIALS Pediatric patients 3 to 10 years of age preparing to undergo RT at 10 institutions were prospectively enrolled. Children able to undergo at least 1 fraction of RT using AVATAR without anesthesia were considered successful (S). Patients requiring anesthesia for their entire treatment course were nonsuccessful (NS). The PedsQL3.0 Cancer Module (PedsQL) survey assessed quality of life and was administered to the patient and guardian at RT simulation, midway through RT, and at final treatment. The modified Yale Preoperative Anxiety Scale (mYPAS) assessed anxiety and was performed at the same 3 time points. Success was evaluated using the χ2 test. PedsQL and mYPAS scores were assessed using mixed effects models with time points evaluated as fixed effects and a random intercept on the subject. RESULTS Eighty-one children were included; median age was 7 years. AVATAR was successful at all 10 institutions and with photon and proton RT. There were 63 (78%) S patients; anesthesia was avoided for a median of 20 fractions per patient. Success differed by age (P = .04) and private versus public insurance (P < .001). Both patient (P = .008) and parent (P = .006) PedsQL scores significantly improved over the course of RT for patients aged 5 to 7. Anxiety in the treatment room decreased for both S and NS patients over RT course (P < .001), by age (P < .001), and by S versus NS patients (P < .001). CONCLUSIONS In this 10-center prospective trial, anesthesia avoidance with AVATAR was 78% in children aged 3 to 10 years, higher than among age-matched historical controls (49%; P < .001). AVATAR implementation is feasible across multiple institutions and should be further studied and made available to patients who may benefit from video-based distraction.
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Affiliation(s)
- Paulina M Gutkin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Medical College of Wisconsin, Wauwatosa, Wisconsin
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Alice Jiang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Sarah S Donaldson
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Justin Oh
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Yi Peng Wang
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Rie von Eyben
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - John Snyder
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Jeremy S Bredfeldt
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - John C Breneman
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Louis S Constine
- Department of Radiation Oncology and Pediatrics, James P. Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, New York
| | - Austin M Faught
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Daphne Haas-Kogan
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Jordan A Holmes
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Matthew Krasin
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Charlene Larkin
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Karen J Marcus
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts
| | - Peter G Maxim
- Department of Radiation Oncology, University of California, Irvine, California
| | - Shearwood McClelland
- Departments of Radiation Oncology and Neurologic Surgery, University Hospitals Seidman Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Blair Murphy
- Department of Radiation Medicine, Oregon Health and Science University, Portland, Oregon
| | - Joshua D Palmer
- Department of Radiation Oncology, Ohio State University School of Medicine, Columbus, Ohio
| | - Stephanie M Perkins
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri
| | - Colette J Shen
- Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - Stephanie Terezakis
- Department of Radiation Oncology, University of Minnesota School of Medicine, Minneapolis, Minnesota
| | - Karl Bush
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Susan M Hiniker
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California.
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Pirlepesov F, Wilson L, Moskvin VP, Breuer A, Parkins F, Lucas JT, Merchant TE, Faught AM. Three-dimensional dose and LET D prediction in proton therapy using artificial neural networks. Med Phys 2022; 49:7417-7427. [PMID: 36227617 PMCID: PMC9872814 DOI: 10.1002/mp.16043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/30/2022] [Accepted: 09/21/2022] [Indexed: 01/26/2023] Open
Abstract
PURPOSE Challenges in proton therapy include identifying patients most likely to benefit; ensuring consistent, high-quality plans as its adoption becomes more widespread; and recognizing biological uncertainties that may be related to increased relative biologic effectiveness driven by linear energy transfer (LET). Knowledge-based planning (KBP) is a domain that may help to address all three. METHODS Artificial neural networks were trained using 117 unique treatment plans and associated dose and dose-weighted LET (LETD ) distributions. The data set was split into training (n = 82), validation (n = 17), and test (n = 18) sets. Model performance was evaluated on the test set using dose- and LETD -volume metrics in the clinical target volume (CTV) and nearby organs at risk and Dice similarity coefficients (DSC) comparing predicted and planned isodose lines at 50%, 75%, and 95% of the prescription dose. RESULTS Dose-volume metrics significantly differed (α = 0.05) between predicted and planned dose distributions in only one dose-volume metric, D2% to the CTV. The maximum observed root mean square (RMS) difference between corresponding metrics was 4.3 GyRBE (8% of prescription) for D1cc to optic chiasm. DSC were 0.90, 0.93, and 0.88 for the 50%, 75%, and 95% isodose lines, respectively. LETD -volume metrics significantly differed in all but one metric, L0.1cc of the brainstem. The maximum observed difference in RMS differences for LETD metrics was 1.0 keV/μm for L0.1cc to brainstem. CONCLUSIONS We have devised the first three-dimensional dose and LETD -prediction model for cranial proton radiation therapy has been developed. Dose accuracy compared favorably with that of previously published models in other treatment sites. The agreement in LETD supports future investigations with biological doses in mind to enable the full potential of KBP in proton therapy.
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Affiliation(s)
- Fakhriddin Pirlepesov
- Department of Radiation Oncology, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
| | - Lydia Wilson
- Department of Radiation Oncology, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
| | - Vadim P. Moskvin
- Department of Radiation Oncology, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
| | - Alex Breuer
- Department of Pathology, St. Jude Children’s
Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105-3678
| | - Franz Parkins
- Department of Information Services, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
| | - John T. Lucas
- Department of Radiation Oncology, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
| | - Thomas E. Merchant
- Department of Radiation Oncology, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
| | - Austin M. Faught
- Department of Radiation Oncology, St. Jude
Children’s Research Hospital, 262 Danny Thomas Place, Memphis, TN,
38105-3678
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Faught AM, Wilson LJ, Gargone M, Pirlepesov F, Moskvin VP, Hua C. Treatment-planning approaches to intensity modulated proton therapy and the impact on dose-weighted linear energy transfer. J Appl Clin Med Phys 2022; 24:e13782. [PMID: 36161765 PMCID: PMC9859995 DOI: 10.1002/acm2.13782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 07/13/2022] [Accepted: 08/16/2022] [Indexed: 01/26/2023] Open
Abstract
PURPOSE We quantified the effect of various forward-based treatment-planning strategies in proton therapy on dose-weighted linear energy transfer (LETd). By maintaining the dosimetric quality at a clinically acceptable level, we aimed to evaluate the differences in LETd among various treatment-planning approaches and their practicality in minimizing biologic uncertainties associated with LETd. METHOD Eight treatment-planning strategies that are achievable in commercial treatment-planning systems were applied on a cylindrical water phantom and four pediatric brain tumor cases. Each planning strategy was compared to either an opposed lateral plan (phantom study) or original clinical plan (patient study). Deviations in mean and maximum LETd from clinically acceptable dose distributions were compared. RESULTS In the phantom study, using a range shifter and altering the robust scenarios during optimization had the largest effect on the mean clinical target volume LETd, which was reduced from 4.5 to 3.9 keV/μm in both cases. Variations in the intersection angle between beams had the largest effect on LETd in a ring defined 3 to 5 mm outside the target. When beam intersection angles were reduced from opposed laterals (180°) to 120°, 90°, and 60°, corresponding maximum LETd increased from 7.9 to 8.9, 10.9, and 12.2 keV/μm, respectively. A clear trend in mean and maximum LETd variations in the clinical cases could not be established, though spatial distribution of LETd suggested a strong dependence on patient anatomy and treatment geometry. CONCLUSION Changes in LETd from treatment-plan setup follow intuitive trends in a controlled phantom experiment. Anatomical and other patient-specific considerations, however, can preclude generalizable strategies in clinical cases. For pediatric cranial radiation therapy, we recommend using opposed lateral treatment fields to treat midline targets.
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Affiliation(s)
- Austin M. Faught
- Department of Radiation OncologySt. Jude Children's Research HospitalMemphisTennesseeUSA
| | - Lydia J. Wilson
- Department of Radiation OncologySt. Jude Children's Research HospitalMemphisTennesseeUSA
| | - Melissa Gargone
- Department of Radiation OncologySt. Jude Children's Research HospitalMemphisTennesseeUSA
| | - Fakhriddin Pirlepesov
- Department of Radiation OncologySt. Jude Children's Research HospitalMemphisTennesseeUSA
| | - Vadim P. Moskvin
- Department of Radiation OncologySt. Jude Children's Research HospitalMemphisTennesseeUSA
| | - Chia‐Ho Hua
- Department of Radiation OncologySt. Jude Children's Research HospitalMemphisTennesseeUSA
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Wilson LJ, Bryce-Atkinson A, Green A, Li Y, Merchant TE, van Herk M, Vasquez Osorio E, Faught AM, Aznar MC. Image-based data mining applies to data collected from children. Phys Med 2022; 99:31-43. [PMID: 35609381 PMCID: PMC9197776 DOI: 10.1016/j.ejmp.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 04/14/2022] [Accepted: 05/07/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Image-based data mining (IBDM) is a novel voxel-based method for analyzing radiation dose responses that has been successfully applied in adult data. Because anatomic variability and side effects of interest differ for children compared to adults, we investigated the feasibility of IBDM for pediatric analyses. METHODS We tested IBDM with CT images and dose distributions collected from 167 children (aged 10 months to 20 years) who received proton radiotherapy for primary brain tumors. We used data from four reference patients to assess IBDM sensitivity to reference selection. We quantified spatial-normalization accuracy via contour distances and deviations of the centers-of-mass of brain substructures. We performed dose comparisons with simplified and modified clinical dose distributions with a simulated effect, assessing their accuracy via sensitivity, positive predictive value (PPV) and Dice similarity coefficient (DSC). RESULTS Spatial normalizations and dose comparisons were insensitive to reference selection. Normalization discrepancies were small (average contour distance < 2.5 mm, average center-of-mass deviation < 6 mm). Dose comparisons identified differences (p < 0.01) in 81% of simplified and all modified clinical dose distributions. The DSCs for simplified doses were high (peak frequency magnitudes of 0.9-1.0). However, the PPVs and DSCs were low (maximum 0.3 and 0.4, respectively) in the modified clinical tests. CONCLUSIONS IBDM is feasible for childhood late-effects research. Our findings may inform cohort selection in future studies of pediatric radiotherapy dose responses and facilitate treatment planning to reduce treatment-related toxicities and improve quality of life among childhood cancer survivors.
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Affiliation(s)
- Lydia J Wilson
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, USA.
| | - Abigail Bryce-Atkinson
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Andrew Green
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Yimei Li
- St. Jude Children's Research Hospital, Department of Biostatistics, Memphis, TN, USA
| | - Thomas E Merchant
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, USA
| | - Marcel van Herk
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Eliana Vasquez Osorio
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Austin M Faught
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, USA
| | - Marianne C Aznar
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Lucas JT, Faught AM, Hsu CY, Wilson LJ, Guo Y, Li Y, Khan R, Becksfort JB, LeVine DA, Ismael Y, Darrow K, Moskvin VP, Pirlepesov F, Klimo P, Elijovich L, Indelicato DJ, Boop FA, Merchant TE. Pre- and Post-therapy Risk Factors for Vasculopathy in Pediatric Craniopharyngioma Patients Treated with Surgery and Proton Radiotherapy. Int J Radiat Oncol Biol Phys 2022; 113:152-160. [PMID: 34990778 DOI: 10.1016/j.ijrobp.2021.12.172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/26/2021] [Accepted: 12/27/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE Vasculopathy (VAS) is a significant complication associated with radiotherapy in patients treated for brain tumors. We studied the type, location, severity, timing, and resolution of VAS in children with craniopharyngioma treated with proton radiotherapy (PRT) and evaluated predictors of stenosis (STN) using a novel patient and imaging-based modelling approach. MATERIALS/METHODS Children with craniopharyngioma (N=94) were treated with 54 GyRBE PRT on a clinical trial NCTXXXXXXXX.1 We evaluated VAS type, location, severity, and resolution. VAS events were segmented and related to their location, operative corridor, PRT dose, and vascular territory to facilitate Mixed Effect Logistic Regression Modelling of spatial predictors of STN events. RESULTS Forty-five (47.9%) patients had 111 instances of confirmed VAS (pre-PRT N = 37, 33.3%). The median time to post-PRT VAS was 3.41 years (95% CI 1.86-6.11). Stenosis events were observed post-PRT in 23.4% (N=22) patients. Post-PRT VAS was detected by cerebral angiogram in 9.6% (N=9), severe in 4.3% (N=4), and compensated on perfusion in 2.1% (N=2). Revascularization was required for 5 (5.3%) patients. Post-surgical, pre-PRT VAS, and PRT dose to unperturbed vessels were predictive of STN. The impact of PRT on STN was negligible within the surgical corridor. CONCLUSIONS VAS often precedes PRT and was the strongest predictor of post-PRT STN. The adverse impact of PRT on STN was only apparent in unperturbed vasculature beyond the operative corridor.
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Affiliation(s)
- John T Lucas
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105.
| | - Austin M Faught
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - Chih Yang Hsu
- GlaxoSmithKline, 812 Springdale Drive, Exton, PA 19341
| | - Lydia J Wilson
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - Yian Guo
- Department of Biostatistics, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - Yimei Li
- Department of Biostatistics, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105.
| | - Raja Khan
- Department of Neurology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Jared B Becksfort
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - David A LeVine
- University of TN Health Sciences Center, 881 Madison Ave Ste 1020, Memphis, TN 38163
| | - Yousef Ismael
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - Kaleb Darrow
- University of TN Health Sciences Center, 881 Madison Ave Ste 1020, Memphis, TN 38163
| | - Vadim P Moskvin
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - Fakhriddin Pirlepesov
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
| | - Paul Klimo
- Department of Surgery, Semmes Murphy, 6325 Humphreys Blvd, Memphis, TN 38120; Division of Pediatric Neurosurgery and Associate Professor, The University of Tennessee Health Science Center
| | - Lucas Elijovich
- Department of Neurology, University of TN Health Sciences Center, 847 Monroe Avenue, Suite 226, Memphis, TN 38163
| | - Daniel J Indelicato
- Department of Radiation Oncology, University of Florida, Jacksonville, FL 32206
| | - Fredrick A Boop
- Department of Surgery, Semmes Murphy, 6325 Humphreys Blvd, Memphis, TN 38120; Division of Pediatric Neurosurgery and Associate Professor, The University of Tennessee Health Science Center
| | - Thomas E Merchant
- Department of Radiation Oncology, St. Jude Children's Research Hospital, 262 Danny Thomas Pl, Memphis, TN 38105
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Wilson LJ, Pirlepesov F, Moskvin V, Li Z, Guo Y, Li Y, Merchant TE, Faught AM. Corrigendum: Proton therapy delivery method affects dose-averaged linear energy transfer in patients (2021 Phys. Med. Biol.66074003). Phys Med Biol 2021; 66. [PMID: 34223826 DOI: 10.1088/1361-6560/ac0b81] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 06/15/2021] [Indexed: 11/12/2022]
Affiliation(s)
- Lydia J Wilson
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Fakhriddin Pirlepesov
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Vadim Moskvin
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Zuofeng Li
- University of Florida Proton Therapy Institute, Department of Radiation Oncology, Jacksonville, FL, United States of America
| | - Yian Guo
- St. Jude Children's Research Hospital, Department of Biostatistics, Memphis, TN, United States of America
| | - Yimei Li
- St. Jude Children's Research Hospital, Department of Biostatistics, Memphis, TN, United States of America
| | - Thomas E Merchant
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Austin M Faught
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
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9
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Dougherty JM, Castillo E, Castillo R, Faught AM, Pepin M, Park SS, Beltran CJ, Guerrero T, Grills I, Vinogradskiy Y. Functional avoidance-based intensity modulated proton therapy with 4DCT derived ventilation imaging for lung cancer. J Appl Clin Med Phys 2021; 22:276-285. [PMID: 34159715 PMCID: PMC8292710 DOI: 10.1002/acm2.13323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 12/25/2022] Open
Abstract
The primary objective is to evaluate the potential dosimetric gains of performing functional avoidance‐based proton treatment planning using 4DCT derived ventilation imaging. 4DCT data of 31 patients from a prospective functional avoidance clinical trial were evaluated with intensity modulated proton therapy (IMPT) plans and compared with clinical volumetric modulated arc therapy (VMAT) plans. Dosimetric parameters were compared between standard and functional plans with IMPT and VMAT with one‐way analysis of variance and post hoc paired student t‐test. Normal Tissue Complication Probability (NTCP) models were employed to estimate the risk of two toxicity endpoints for healthy lung tissues. Dose degradation due to proton motion interplay effect was evaluated. Functional IMPT plans led to significant dose reduction to functional lung structures when compared with functional VMAT without significant dose increase to Organ at Risk (OAR) structures. When interplay effect is considered, no significant dose degradation was observed for the OARs or the clinical target volume (CTV) volumes for functional IMPT. Using fV20 as the dose metric and Grade 2+ pneumonitis as toxicity endpoint, there is a mean 5.7% reduction in Grade 2+ RP with the functional IMPT and as high as 26% in reduction for individual patient when compared to the standard IMPT planning. Functional IMPT was able to spare healthy lung tissue to avoid excess dose to normal structures while maintaining satisfying target coverage. NTCP calculation also shows that the risk of pulmonary complications can be further reduced with functional based IMPT.
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Affiliation(s)
| | - Edward Castillo
- Department of Computational and Applied Mathematics, Rice University, Houston, TX, USA.,Department of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA
| | - Richard Castillo
- Department of Radiation Oncology, Emory University, Atlanta, GA, USA
| | - Austin M Faught
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Mark Pepin
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Sean S Park
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Chris J Beltran
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, USA
| | - Thomas Guerrero
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA
| | - Inga Grills
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, MI, USA
| | - Yevgeniy Vinogradskiy
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, CO, USA
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10
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Wilson LJ, Pirlepesov F, Moskvin V, Li Z, Guo Y, Li Y, Merchant TE, Faught AM. Proton therapy delivery method affects dose-averaged linear energy transfer in patients. Phys Med Biol 2021; 66. [PMID: 33607632 DOI: 10.1088/1361-6560/abe835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 02/19/2021] [Indexed: 11/11/2022]
Abstract
The dosimetric advantages of proton therapy have led to its rapid proliferation in recent decades. This has been accompanied by a shift in technology from older units that deliver protons by passive scattering (PS) to newer units that increasingly use pencil-beam scanning (PBS). The biologic effectiveness of proton physical dose purportedly rises with increasing dose-weighted average linear energy transfer (LETD). The objective of this study was to determine the extent to which proton delivery methods affect LETD. We calculated LETDfrom simple, dosimetrically matched, and clinical treatment plans with TOPAS Monte-Carlo transport code. Simple treatment plans comprised single fields of PS and PBS protons in a water phantom. We performed simulations of matched and clinical treatment plans by using the treatment and anatomic data obtained from a cohort of children with craniopharyngioma who previously received PS or PBS proton therapy. We compared the distributions of LETDfrom PS and PBS delivery methods in clinically relevant ROIs. Wilcoxon signed-rank tests comparing single fields in water revealed that the LETDvalues from PBS were significantly greater than those from PS inside and outside the targeted volume (p < 0.01). Statistical tests comparing LETD-volume histograms from matched and clinical treatment plans showed that LETDwas generally greater for PBS treatment plans than for PS treatment plans (p < 0.05). In conclusion, the proton delivery method affects LETDboth inside and outside of the target volume. These findings suggest that PBS is more biologically effective than PS. Given the rapid expansion of PBS proton therapy, future studies are needed to confirm the applicability of treatment evaluation methods developed for PS proton therapy to those for modern PBS treatments to ensure their safety and effectiveness for the growing population of patients receiving proton therapy. This study uses data from two clinical trials: NCT01419067 and NCT02792582.
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Affiliation(s)
- Lydia J Wilson
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Fakhriddin Pirlepesov
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Vadim Moskvin
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Zuofeng Li
- University of Florida Proton Therapy Institute, Department of Radiation Oncology, Jacksonville, FL, United States of America
| | - Yian Guo
- St. Jude Children's Research Hospital, Department of Biostatistics, Memphis, TN, United States of America
| | - Yimei Li
- St. Jude Children's Research Hospital, Department of Biostatistics, Memphis, TN, United States of America
| | - Thomas E Merchant
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
| | - Austin M Faught
- St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, TN, United States of America
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11
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Kaluarachchi M, Moskvin V, Pirlepesov F, Wilson LJ, Xie F, Faught AM. Automation of Monte Carlo-based treatment plan verification for proton therapy. J Appl Clin Med Phys 2020; 21:131-138. [PMID: 32452657 PMCID: PMC7484839 DOI: 10.1002/acm2.12923] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 04/03/2020] [Accepted: 04/28/2020] [Indexed: 01/04/2023] Open
Abstract
Purpose Independent calculations of proton therapy plans are an important quality control procedure in treatment planning. When using custom Monte Carlo (MC) models of the beamline, deploying the calculations can be laborious, time consuming, and require in‐depth knowledge of the computational environment. We developed an automated framework to remove these barriers and integrate our MC model into the clinical workflow. Materials and Methods The Eclipse Scripting Application Programming Interface was used to initiate the automation process. A series of MATLAB scripts were then used for preprocessing of input data and postprocessing of results. Additional scripts were used to monitor the calculation process and appropriately deploy calculations to an institutional high‐performance computing facility. The automated framework and beamline models were validated against 160 patient specific QA measurements from an ionization chamber array and using a ±3%/3 mm gamma criteria. Results The automation reduced the human‐hours required to initiate and run a calculation to 1–2 min without leaving the treatment planning system environment. Validation comparisons had an average passing rate of 99.4% and were performed at depths ranging from 1 to 15 cm. Conclusion An automated framework for running MC calculations was developed which enables the calculation of dose and linear energy transfer within a clinically relevant workflow and timeline. The models and framework were validated against patient specific QA measurements and exhibited excellent agreement. Before this implementation, execution was prohibitively complex for an untrained individual and its use restricted to a research environment.
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Affiliation(s)
- Maduka Kaluarachchi
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Vadim Moskvin
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Fakhriddin Pirlepesov
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Lydia J Wilson
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Fang Xie
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Austin M Faught
- Department of Radiation Oncology, St. Jude Children's Research Hospital, Memphis, TN, USA
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12
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Ashcraft KA, Hannan JL, Eichenbaum G, Zhang X, Pak ES, Faught AM, Patel P, Dewhirst MW, Koontz BF. Clarifying the Relative Impacts of Vascular and Nerve Injury That Culminate in Erectile Dysfunction in a Pilot Study Using a Rat Model of Prostate Irradiation and a Thrombopoietin Mimetic. Int J Radiat Oncol Biol Phys 2018; 103:1212-1220. [PMID: 30529374 DOI: 10.1016/j.ijrobp.2018.11.064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 11/27/2018] [Accepted: 11/29/2018] [Indexed: 12/24/2022]
Abstract
PURPOSE Radiation therapy (RT) offers an important and curative approach to treating prostate cancer, but it is associated with a high incidence of erectile dysfunction (ED). It is not clear whether the etiology of radiation-induced ED (RI-ED) is driven by RT-mediated injury to the vasculature, the nerves, or both. This pilot study sought to distinguish the effects of vascular and nerve injury in RI-ED by applying a vascular radioprotectant in a rat model of prostate RT. METHODS A single dose of the thrombopoietin mimetic (TPOm; RWJ-800088), previously shown to mitigate radiation-induced vascular injury, was administered 10 minutes after single-fraction conformal prostate RT. Nine weeks after RT, rats were assessed for erectile and arterial function. Nerve markers were quantified with reverse transcriptase polymerase chain reaction. Immunofluorescent microscopy further characterized vascular effects of RT and TPOm. RESULTS Sham animals and animals that received RT and TPOm showed significant arterial vasodilation in response to systemic hydralazine (24.1% ± 7.3% increase; P = .03 in paired t test). However, animals that received RT and vehicle were unable to mount a vasodilatory response (-7.4% ± 9.9% increase; P = .44 in paired t test). TPOm prevented RT-induced change in the penile artery cross-sectional area (P = .036), but it did not ameliorate cavernous nerve injury as evaluated by gene expression of neuronal injury markers. Despite significant structural and functional vascular protective effects and some trends for differences in nerve injury/recovery markers, TPOm did not prevent RI-ED at 9 weeks, as assessed by intracavernous pressure monitoring after cavernous nerve stimulation. CONCLUSIONS These data suggest that vascular protection alone is not sufficient to prevent RI-ED and that cavernous nerve injury plays a key role in RI-ED. Further research is required to delineate the multifactorial nature of RI-ED and to determine if TPOm with modified dosing regimens can mitigate against nerve injury either through direct or vascular protective effects.
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Affiliation(s)
- Kathleen A Ashcraft
- Duke University School of Medicine, Department of Radiation Oncology, Durham, North Carolina
| | - Johanna L Hannan
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Gary Eichenbaum
- Johnson & Johnson, Office of the Chief Medical Officer, New Brunswick, New Jersey
| | - Xiaojie Zhang
- Duke University School of Medicine, Department of Radiation Oncology, Durham, North Carolina
| | - Elena S Pak
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina
| | - Austin M Faught
- Duke University School of Medicine, Department of Radiation Oncology, Durham, North Carolina
| | - Pranalee Patel
- Duke University School of Medicine, Department of Radiation Oncology, Durham, North Carolina
| | - Mark W Dewhirst
- Duke University School of Medicine, Department of Radiation Oncology, Durham, North Carolina
| | - Bridget F Koontz
- Duke University School of Medicine, Department of Radiation Oncology, Durham, North Carolina.
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13
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Hong JC, Cui Y, Patel BN, Rushing CN, Faught AM, Eng JS, Higgins K, Yin FF, Das S, Czito BG, Willett CG, Palta M. Association of Interim FDG-PET Imaging During Chemoradiation for Squamous Anal Canal Carcinoma With Recurrence. Int J Radiat Oncol Biol Phys 2018; 102:1046-1051. [DOI: 10.1016/j.ijrobp.2018.04.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/08/2018] [Accepted: 04/23/2018] [Indexed: 10/17/2022]
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14
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Faught AM, Olsen L, Schubert L, Rusthoven C, Castillo E, Castillo R, Zhang J, Guerrero T, Miften M, Vinogradskiy Y. Functional-guided radiotherapy using knowledge-based planning. Radiother Oncol 2018; 129:494-498. [PMID: 29628292 DOI: 10.1016/j.radonc.2018.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 03/12/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND AND PURPOSE There are two significant challenges when implementing functional-guided radiotherapy using 4DCT-ventilation imaging: (1) lack of knowledge of realistic patient specific dosimetric goals for functional lung and (2) ensuring consistent plan quality across multiple planners. Knowledge-based planning (KBP) is positioned to address both concerns. MATERIAL AND METHODS A KBP model was created from 30 previously planned functional-guided lung patients. Standard organs at risk (OAR) in lung radiotherapy and a ventilation contour delineating areas of high ventilation were included. Model validation compared dose-metrics to standard OARs and functional dose-metrics from 20 independent cases that were planned with and without KBP. RESULTS A significant improvement was observed for KBP optimized plans in V20Gy and mean dose to functional lung (p = 0.005 and 0.001, respectively), V20Gy and mean dose to total lung minus GTV (p = 0.002 and 0.01, respectively), and mean doses to esophagus (p = 0.005). CONCLUSION The current work developed a KBP model for functional-guided radiotherapy. Modest, but statistically significant, improvements were observed in functional lung and total lung doses.
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Affiliation(s)
- Austin M Faught
- University of Colorado School of Medicine, Department of Radiation Oncology, Aurora, United States; St. Jude Children's Research Hospital, Department of Radiation Oncology, Memphis, United States.
| | - Lindsey Olsen
- Memorial Hospital, Department of Radiation Oncology, Colorado Springs, United States
| | - Leah Schubert
- University of Colorado School of Medicine, Department of Radiation Oncology, Aurora, United States
| | - Chad Rusthoven
- University of Colorado School of Medicine, Department of Radiation Oncology, Aurora, United States
| | - Edward Castillo
- Beaumont Health System, Department of Radiation Oncology, Royal Oak, United States
| | - Richard Castillo
- Emory University, Department of Radiation Oncology, Atlanta, United States
| | - Jingjing Zhang
- Beaumont Health System, Department of Radiation Oncology, Royal Oak, United States
| | - Thomas Guerrero
- Beaumont Health System, Department of Radiation Oncology, Royal Oak, United States
| | - Moyed Miften
- University of Colorado School of Medicine, Department of Radiation Oncology, Aurora, United States
| | - Yevgeniy Vinogradskiy
- University of Colorado School of Medicine, Department of Radiation Oncology, Aurora, United States
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15
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Faught AM, Davidson SE, Popple R, Kry SF, Etzel C, Ibbott GS, Followill DS. Development of a flattening filter free multiple source model for use as an independent, Monte Carlo, dose calculation, quality assurance tool for clinical trials. Med Phys 2017; 44:4952-4960. [PMID: 28657114 DOI: 10.1002/mp.12433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 11/10/2022] Open
Abstract
PURPOSE The Imaging and Radiation Oncology Core-Houston (IROC-H) Quality Assurance Center (formerly the Radiological Physics Center) has reported varying levels of compliance from their anthropomorphic phantom auditing program. IROC-H studies have suggested that one source of disagreement between institution submitted calculated doses and measurement is the accuracy of the institution's treatment planning system dose calculations and heterogeneity corrections used. In order to audit this step of the radiation therapy treatment process, an independent dose calculation tool is needed. METHODS Monte Carlo multiple source models for Varian flattening filter free (FFF) 6 MV and FFF 10 MV therapeutic x-ray beams were commissioned based on central axis depth dose data from a 10 × 10 cm2 field size and dose profiles for a 40 × 40 cm2 field size. The models were validated against open-field measurements in a water tank for field sizes ranging from 3 × 3 cm2 to 40 × 40 cm2 . The models were then benchmarked against IROC-H's anthropomorphic head and neck phantom and lung phantom measurements. RESULTS Validation results, assessed with a ±2%/2 mm gamma criterion, showed average agreement of 99.9% and 99.0% for central axis depth dose data for FFF 6 MV and FFF 10 MV models, respectively. Dose profile agreement using the same evaluation technique averaged 97.8% and 97.9% for the respective models. Phantom benchmarking comparisons were evaluated with a ±3%/2 mm gamma criterion, and agreement averaged 90.1% and 90.8% for the respective models. CONCLUSIONS Multiple source models for Varian FFF 6 MV and FFF 10 MV beams have been developed, validated, and benchmarked for inclusion in an independent dose calculation quality assurance tool for use in clinical trial audits.
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Affiliation(s)
- Austin M Faught
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - Scott E Davidson
- Department of Radiation Oncology, The University of Texas Medical Branch of Galveston, Galveston, TX, 77555, USA
| | - Richard Popple
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Stephen F Kry
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - Carol Etzel
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,Consortium of Rheumatology Researchers of North America (CORRONA), Inc., Southborough, MA, 01772, USA
| | - Geoffrey S Ibbott
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - David S Followill
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
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16
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Faught AM, Davidson SE, Fontenot J, Kry SF, Etzel C, Ibbott GS, Followill DS. Development of a Monte Carlo multiple source model for inclusion in a dose calculation auditing tool. Med Phys 2017. [PMID: 28640950 DOI: 10.1002/mp.12426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE The Imaging and Radiation Oncology Core Houston (IROC-H) (formerly the Radiological Physics Center) has reported varying levels of agreement in their anthropomorphic phantom audits. There is reason to believe one source of error in this observed disagreement is the accuracy of the dose calculation algorithms and heterogeneity corrections used. To audit this component of the radiotherapy treatment process, an independent dose calculation tool is needed. METHODS Monte Carlo multiple source models for Elekta 6 MV and 10 MV therapeutic x-ray beams were commissioned based on measurement of central axis depth dose data for a 10 × 10 cm2 field size and dose profiles for a 40 × 40 cm2 field size. The models were validated against open field measurements consisting of depth dose data and dose profiles for field sizes ranging from 3 × 3 cm2 to 30 × 30 cm2 . The models were then benchmarked against measurements in IROC-H's anthropomorphic head and neck and lung phantoms. RESULTS Validation results showed 97.9% and 96.8% of depth dose data passed a ±2% Van Dyk criterion for 6 MV and 10 MV models respectively. Dose profile comparisons showed an average agreement using a ±2%/2 mm criterion of 98.0% and 99.0% for 6 MV and 10 MV models respectively. Phantom plan comparisons were evaluated using ±3%/2 mm gamma criterion, and averaged passing rates between Monte Carlo and measurements were 87.4% and 89.9% for 6 MV and 10 MV models respectively. CONCLUSIONS Accurate multiple source models for Elekta 6 MV and 10 MV x-ray beams have been developed for inclusion in an independent dose calculation tool for use in clinical trial audits.
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Affiliation(s)
- Austin M Faught
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA.,Department of Radiation Oncology, University of Colorado School of Medicine, Denver, CO, 80045, USA
| | - Scott E Davidson
- Department of Radiation Oncology, The University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Jonas Fontenot
- Department of Physics, Mary Bird Perkins Cancer Center, Baton Rouge, LA, 70809, USA
| | - Stephen F Kry
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - Carol Etzel
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,Consortium of Rheumatology Researchers of North America (CORRONA), Inc., Southborough, MA, 01772, USA
| | - Geoffrey S Ibbott
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - David S Followill
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
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17
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Faught AM, Miyasaka Y, Kadoya N, Castillo R, Castillo E, Vinogradskiy Y, Yamamoto T. Evaluating the Toxicity Reduction With Computed Tomographic Ventilation Functional Avoidance Radiation Therapy. Int J Radiat Oncol Biol Phys 2017; 99:325-333. [PMID: 28871982 DOI: 10.1016/j.ijrobp.2017.04.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/02/2017] [Accepted: 04/12/2017] [Indexed: 02/02/2023]
Abstract
PURPOSE Computed tomographic (CT) ventilation imaging is a new modality that uses 4-dimensional (4D) CT information to calculate lung ventilation. Although retrospective studies have reported on the reduction in dose to functional lung, no work to our knowledge has been published in which the dosimetric improvements have been translated to a reduction in the probability of pulmonary toxicity. Our work estimates the reduction in toxicity for CT ventilation-based functional avoidance planning. METHODS AND MATERIALS Seventy previously treated lung cancer patients who underwent 4DCT imaging were used for the study. CT ventilation maps were calculated with 4DCT deformable image registration and a density change-based algorithm. Pneumonitis was graded on the basis of imaging and clinical presentation. Maximum likelihood methods were used to generate normal tissue complication probability (NTCP) models predicting grade 2 or higher (2+) and grade 3+ pneumonitis as a function of dose (V5 Gy, V10 Gy, V20 Gy, V30 Gy, and mean dose) to functional lung. For 30 patients a functional plan was generated with the goal of reducing dose to the functional lung while meeting Radiation Therapy Oncology Group 0617 constraints. The NTCP models were applied to the functional plans and the clinically used plans to calculate toxicity reduction. RESULTS By the use of functional avoidance planning, absolute reductions in grade 2+ NTCP of 6.3%, 7.8%, and 4.8% were achieved based on the mean fV20 Gy, fV30 Gy, and mean dose to functional lung metrics, respectively. Absolute grade 3+ NTCP reductions of 3.6%, 4.8%, and 2.4% were achieved with fV20 Gy, fV30 Gy, and mean dose to functional lung. Maximum absolute reductions of 52.3% and 16.4% were seen for grade 2+ and grade 3+ pneumonitis for individual patients. CONCLUSION Our study quantifies the possible toxicity reduction from CT ventilation-based functional avoidance planning. Reductions in grades 2+ and 3+ pneumonitis were 7.1% and 4.7% based on mean dose-function metrics, with reductions as high as 52.3% for individual patients. Our work provides seminal data for determining the potential toxicity benefit from incorporating CT ventilation into thoracic treatment planning.
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Affiliation(s)
- Austin M Faught
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
| | - Yuya Miyasaka
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Noriyuki Kadoya
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Richard Castillo
- Department of Radiation Oncology, University of Texas Medical Branch of Galveston, League City, Texas
| | - Edward Castillo
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan
| | - Yevgeniy Vinogradskiy
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Tokihiro Yamamoto
- Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, California
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18
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Faught AM, Yamamoto T, Castillo R, Castillo E, Zhang J, Miften M, Vinogradskiy Y. Evaluating Which Dose-Function Metrics Are Most Critical for Functional-Guided Radiation Therapy. Int J Radiat Oncol Biol Phys 2017; 99:202-209. [PMID: 28816147 DOI: 10.1016/j.ijrobp.2017.03.051] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/30/2017] [Indexed: 02/08/2023]
Abstract
PURPOSE Four-dimensional (4D) computed tomography (CT) ventilation imaging is increasingly being used to calculate lung ventilation and implement functional-guided radiation therapy in clinical trials. There has been little exhaustive work evaluating which dose-function metrics should be used for treatment planning and plan evaluation. The purpose of our study was to evaluate which dose-function metrics best predict for radiation pneumonitis (RP). METHODS AND MATERIALS Seventy lung cancer patients who underwent 4D CT imaging and pneumonitis grading were assessed. Pretreatment 4D CT scans of each patient were used to calculate ventilation images. We evaluated 3 types of dose-function metrics that combined the patient's 4D CT ventilation image and treatment planning dose distribution: (1) structure-based approaches; (2) image-based approaches using the dose-function histogram; and (3) nonlinear weighting schemes. Log-likelihood methods were used to generate normal tissue complication probability models predicting grade 3 or higher (ie, grade 3+) pneumonitis for all dose-function schemes. The area under the curve (AUC) was used to assess the predictive power of the models. All techniques were compared with normal tissue complication probability models based on traditional, total lung dose metrics. RESULTS The most predictive models were structure-based approaches that focused on the volume of functional lung receiving ≥20 Gy (AUC, 0.70). Probabilities of grade 3+ RP of 20% and 10% correspond to V20 (percentage of volume receiving ≥20 Gy) to the functional subvolumes of 26.8% and 9.3%, respectively. Imaging-based analysis with the dose-function histogram and nonlinear weighted ventilation values yielded AUCs of 0.66 and 0.67, respectively, when we evaluated the percentage of functionality receiving ≥20 Gy. All dose-function metrics outperformed the traditional dose metrics (mean lung dose, AUC of 0.55). CONCLUSIONS A full range of dose-function metrics and functional thresholds was examined. The calculated AUC values for the most predictive functional models occupied a narrow range (0.66-0.70), and all showed notable improvements over AUC from traditional lung dose metrics (0.55). Identifying the combinations most predictive of grade 3+ RP provides valuable data to inform the functional-guided radiation therapy process.
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Affiliation(s)
- Austin M Faught
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado.
| | - Tokihiro Yamamoto
- Department of Radiation Oncology, University of California Davis School of Medicine, Sacramento, California
| | - Richard Castillo
- Department of Radiation Oncology, University of Texas Medical Branch of Galveston, League City, Texas
| | - Edward Castillo
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan
| | - Jingjing Zhang
- Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan
| | - Moyed Miften
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Yevgeniy Vinogradskiy
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
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Faught AM, Trager M, Yin FF, Kirkpatrick J, Adamson J. Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery. Med Phys 2017; 43:5437. [PMID: 27782700 DOI: 10.1118/1.4962471] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The recent development of multifocal stereotactic radiosurgery (SRS) using a single isocenter volumetric modulated arc theory (VMAT) technique warrants a re-examination of the quality assurance (QA) tolerances for routine mechanical QA recommended by the American Association of Physicists in Medicine Task Group Report Number 142. Multifocal SRS can result in targets with small volumes being at a large off-axis distance from the treatment isocenter. Consequently, angular errors in the collimator, patient support assembly (PSA), or gantry could have an increased impact on target coverage. METHODS The authors performed a retrospective analysis of dose deviations caused by systematic errors in PSA, collimator, and gantry angle at the tolerance level for routine linear accelerator QA as recommended by TG-142. Dosimetric deviations from multifocal SRS plans (N = 10) were compared to traditional single target SRS using dynamic conformal arcs (N = 10). The chief dosimetric quantities used in determining clinical impact were V100% and D99% of the individual planning target volumes and V12Gy of the healthy brain. RESULTS Induced errors at tolerance levels showed the greatest change in multifocal SRS target coverage for collimator rotations (±1.0°) with the average changes to V100% and D99% being 5% and 6%, respectively, with maximum changes of 33% and 20%. A reduction in the induced error to half the TG-142 tolerance (±0.5°) demonstrated similar changes in coverage loss to traditional single target SRS assessed at the recommended tolerance level. The observed change in coverage for multifocal SRS was reduced for gantry errors (±1.0°) at 2% and 4.5% for V100% and D99%, respectively, with maximum changes of 18% and 12%. Minimal change in coverage was noted for errors in PSA rotation. CONCLUSIONS This study indicates that institutions utilizing a single isocenter VMAT technique for multifocal disease should pay careful attention to the angular mechanical tolerances in designing a robust and complete QA program.
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Affiliation(s)
- Austin M Faught
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - Michael Trager
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - John Kirkpatrick
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - Justus Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
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20
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Faught AM, Yin F, Adamson J. An in-house protocol for improved flood field calibration of TrueBeam FFF cine imaging. J Appl Clin Med Phys 2017; 18:265-268. [PMID: 28291919 PMCID: PMC5689880 DOI: 10.1002/acm2.12023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/07/2016] [Indexed: 11/17/2022] Open
Abstract
PURPOSE TrueBeams equipped with the 40 × 30 cm2 Electronic Portal Imaging Devices (EPIDs) are prone to image saturation at the image center when used with flattening filter free (FFF) photon energies. While cine imaging during treatment may not saturate because the beam is attenuated by the patient, the flood field calibration is affected when the standard calibration procedure is followed. Here, we describe the hardware and protocol to achieve improved image quality for this model of TrueBeam EPID. MATERIALS & METHODS A stainless steel filter of uniform thickness was designed to have sufficient attenuation to avoid panel saturation. The cine imaging flood field calibration was acquired with the filter in place for the FFF energies under the standard calibration geometry (SID = 150 cm). Image quality during MV cine was assessed with & without the modified flood field calibration using a low contrast resolution phantom and an anthropomorphic phantom. RESULTS When the flood field is acquired without the filter in place, a pixel gain artifact is clearly present in the image center which may be mis-attributed to panel saturation in the subject image. At the image center, the artifact obscured all low contrast inserts and was also visible on the anthropomorphic phantom. Using the filter for flood field calibration eliminates the artifact. CONCLUSION TrueBeams equipped with the 40 × 30 cm2 IDU can utilize a modified flood field calibration procedure for FFF photon energies that improves image quality for cine MV imaging.
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Affiliation(s)
- Austin M. Faught
- Department of Radiation OncologyDuke University Medical CenterDurhamNC27710USA,Department of Radiation OncologyUniversity of Colorado School of MedicineAuroraCO80045USA
| | - Fang‐Fang Yin
- Department of Radiation OncologyDuke University Medical CenterDurhamNC27710USA
| | - Justus Adamson
- Department of Radiation OncologyDuke University Medical CenterDurhamNC27710USA
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21
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Kry SF, Molineu A, Kerns JR, Faught AM, Huang JY, Pulliam KB, Tonigan J, Alvarez P, Stingo F, Followill DS. Institutional patient-specific IMRT QA does not predict unacceptable plan delivery. Int J Radiat Oncol Biol Phys 2014; 90:1195-201. [PMID: 25442044 PMCID: PMC4276500 DOI: 10.1016/j.ijrobp.2014.08.334] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 08/14/2014] [Accepted: 08/18/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To determine whether in-house patient-specific intensity modulated radiation therapy quality assurance (IMRT QA) results predict Imaging and Radiation Oncology Core (IROC)-Houston phantom results. METHODS AND MATERIALS IROC Houston's IMRT head and neck phantoms have been irradiated by numerous institutions as part of clinical trial credentialing. We retrospectively compared these phantom results with those of in-house IMRT QA (following the institution's clinical process) for 855 irradiations performed between 2003 and 2013. The sensitivity and specificity of IMRT QA to detect unacceptable or acceptable plans were determined relative to the IROC Houston phantom results. Additional analyses evaluated specific IMRT QA dosimeters and analysis methods. RESULTS IMRT QA universally showed poor sensitivity relative to the head and neck phantom, that is, poor ability to predict a failing IROC Houston phantom result. Depending on how the IMRT QA results were interpreted, overall sensitivity ranged from 2% to 18%. For different IMRT QA methods, sensitivity ranged from 3% to 54%. Although the observed sensitivity was particularly poor at clinical thresholds (eg 3% dose difference or 90% of pixels passing gamma), receiver operator characteristic analysis indicated that no threshold showed good sensitivity and specificity for the devices evaluated. CONCLUSIONS IMRT QA is not a reasonable replacement for a credentialing phantom. Moreover, the particularly poor agreement between IMRT QA and the IROC Houston phantoms highlights surprising inconsistency in the QA process.
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Affiliation(s)
- Stephen F Kry
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
| | - Andrea Molineu
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - James R Kerns
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas
| | - Austin M Faught
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas
| | - Jessie Y Huang
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas
| | - Kiley B Pulliam
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas
| | - Jackie Tonigan
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas
| | - Paola Alvarez
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Francesco Stingo
- The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas; Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - David S Followill
- Imaging and Radiation Oncology Core at Houston, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas; The University of Texas Health Science Center Houston, Graduate School of Biomedical Sciences, Houston, Texas
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Faught AM, Kry SF, Luo D, Molineu A, Bellezza D, Gerber RL, Davidson SE, Bosch W, Drzymala RE, Galvin J, Timmerman R, Sheehan J, Gillin MT, Ibbott GS, Followill DS. Development of a modified head and neck quality assurance phantom for use in stereotactic radiosurgery trials. J Appl Clin Med Phys 2013; 14:4313. [PMID: 23835394 PMCID: PMC5714534 DOI: 10.1120/jacmp.v14i4.4313] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/05/2013] [Accepted: 03/01/2013] [Indexed: 11/25/2022] Open
Abstract
An anthropomorphic head phantom, constructed from a water‐equivalent plastic shell with only a spherical target, was modified to include a nonspherical target (pituitary) and an adjacent organ at risk (OAR) (optic chiasm), within 2 mm, simulating the anatomy encountered when treating acromegaly. The target and OAR spatial proximity provided a more realistic treatment planning and dose delivery exercise. A separate dosimetry insert contained two TLD for absolute dosimetry and radiochromic film, in the sagittal and coronal planes, for relative dosimetry. The prescription was 25 Gy to 90% of the GTV, with ≤10% of the OAR volume receiving ≥8Gy for the phantom trial. The modified phantom was used to test the rigor of the treatment planning process and phantom reproducibility using a Gamma Knife, CyberKnife, and linear accelerator (linac)‐based radiosurgery system. Delivery reproducibility was tested by repeating each irradiation three times. TLD results from three irradiations on a CyberKnife and Gamma Knife agreed with the calculated target dose to within ± 4% with a maximum coefficient of variation of ±2.1%. Gamma analysis in the coronal and sagittal film planes showed an average passing rate of 99.4% and 99.5% using ±5%/3mm criteria, respectively. Results from the linac irradiation were within ±6.2% for TLD with a coefficient of variation of ±0.1%. Distance to agreement was calculated to be 1.2 mm and 1.3 mm along the inferior and superior edges of the target in the sagittal film plane, and 1.2 mm for both superior and inferior edges in the coronal film plane. A modified, anatomically realistic SRS phantom was developed that provided a realistic clinical planning and delivery challenge that can be used to credential institutions wanting to participate in NCI‐funded clinical trials. PACS number: 87.55 ‐v
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Affiliation(s)
- Austin M Faught
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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