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Hrbacek J, Kacperek A, Beenakker JWM, Mortimer L, Denker A, Mazal A, Shih HA, Dendale R, Slopsema R, Heufelder J, Mishra KK. PTCOG Ocular Statement: Expert Summary of Current Practices and Future Developments in Ocular Proton Therapy. Int J Radiat Oncol Biol Phys 2024:S0360-3016(24)00748-X. [PMID: 38971383 DOI: 10.1016/j.ijrobp.2024.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 05/08/2024] [Accepted: 06/18/2024] [Indexed: 07/08/2024]
Abstract
Although rare cancers, ocular tumors are a threat to vision, quality of life, and potentially life expectancy of a patient. Ocular proton therapy (OPT) is a powerful tool for successfully treating this disease. The Particle Therapy Co-Operative Ocular Group) formulated an Evidence and Expert-Based Executive Summary of Current Practices and Future Developments in OPT: comparative dosimetric and clinical analysis with the different OPT systems is essential to set up planning guidelines, implement best practices, and establish benchmarks for eye preservation, vision, and quality of life measures. Contemporary prospective trials in select subsets of patients (eg, tumors near the optic disc and/or macula) may allow for dosimetric and clinical analysis between different radiation modalities and beamline systems to evaluate differences in radiation delivery and penumbra, and resultant tumor control, normal tissue complication rates, and overall clinical cost-effectiveness. To date, the combination of multimodal imaging (fundus photography, ultrasound, etc), ophthalmologist assessment, and clip surgery with radiation planning have been keys to successful treatment. Increased use of three-dimensional imaging (computed tomography/magnetic resonance imaging) is anticipated although its spatial resolution might be a limiting factor (eg, detection of flat diffuse tumor parts). Commercially produced ocular treatment-planning systems are under development and their future use is expected to expand across OPT centers. Future continuity of OPT will depend on the following: (1) maintaining and upgrading existing older dedicated low-energy facilities, (2) maintaining shared, degraded beamlines at large proton therapy centers, and (3) developing adapted gantry beams of sufficient quality to maintain the clinical benefits of sharp beam conformity. Option (1) potentially offers the sharpest beams, minimizing impact on healthy tissues, whereas (2) and (3) potentially offer the advantage of substantial long-term technical support and development as well as the introduction of new approaches. Significant patient throughputs and close cooperation between medical physics, ophthalmology, and radiation therapy, underpinned by mutual understanding, is crucial for a successful OPT service.
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Affiliation(s)
- Jan Hrbacek
- Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland.
| | | | - Jan-Willem M Beenakker
- Department of Ophthalmology, Leiden University Medical Center, Leiden, Netherlands; Department of Radiology, C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, Netherlands; Department of Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands; HollandPTC, Delft, Netherlands
| | - Linda Mortimer
- Medical Physics Department, The Clatterbridge Cancer Centre NHS Foundation Trust, Birkenhead, United Kingdom
| | - Andrea Denker
- Helmholtz-Zentrum Berlin für Materialien und Energie, Proton Therapy (BE-APT), Berlin, Germany
| | - Alejandro Mazal
- Medical Physics Service, Centro de Protonterapia Quironsalud, Madrid, Spain
| | - Helen A Shih
- Harvard Medical School, Boston, Massachusetts; Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts
| | - Remi Dendale
- Institut Curie Protontherapy Center, Orsay, France
| | - Roelf Slopsema
- Department of Radiation Oncology, Emory Proton Therapy Center, Atlanta, Georgia
| | - Jens Heufelder
- Department of Ophthalmology, Charité - Universitätsmedizin Berlin, BerlinProtonen am HZB, Berlin, Germany
| | - Kavita K Mishra
- Proton Ocular Radiation Therapy Program, Department of Radiation Oncology, Osher Center for Integrative Health, Osher Foundation Endowed Chair in Clinical Programs in Integrative Health, University of California San Francisco, San Francisco, California
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Fleury E, Pignol JP, Kiliç E, Milder M, van Rij C, Naus N, Yavuzyigitoglu S, den Toom W, Zolnay A, Spruijt K, van Vulpen M, Trnková P, Hoogeman M. Comparison of stereotactic radiotherapy and protons for uveal melanoma patients. Phys Imaging Radiat Oncol 2024; 31:100605. [PMID: 39050744 PMCID: PMC11268348 DOI: 10.1016/j.phro.2024.100605] [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: 01/22/2024] [Revised: 06/21/2024] [Accepted: 06/25/2024] [Indexed: 07/27/2024] Open
Abstract
Background and purpose Uveal melanoma (UM) is the most common primary ocular malignancy. We compared fractionated stereotactic radiotherapy (SRT) with proton therapy, including toxicity risks for UM patients. Materials and methods For a total of 66 UM patients from a single center, SRT dose distributions were compared to protons using the same planning CT. Fourteen dose-volume parameters were compared in 2-Gy equivalent dose per fraction (EQD2). Four toxicity profiles were evaluated: maculopathy, optic-neuropathy, visual acuity impairment (Profile I); neovascular glaucoma (Profile II); radiation-induced retinopathy (Profile III); and dry-eye syndrome (Profile IV). For Profile III, retina Mercator maps were generated to visualize the geographical location of dose differences. Results In 9/66 cases, (14 %) proton plans were superior for all dose-volume parameters. Higher T stages benefited more from protons in Profile I, especially tumors located within 3 mm or less from the optic nerve. In Profile II, only 9/66 cases resulted in a better proton plan. In Profile III, better retina volume sparing was always achievable with protons, with a larger gain for T3 tumors. In Profile IV, protons always reduced the risk of toxicity with a median RBE-weighted EQD2 reduction of 15.3 Gy. Conclusions This study reports the first side-by-side imaging-based planning comparison between protons and SRT for UM patients. Globally, while protons appear almost always better regarding the risk of optic-neuropathy, retinopathy and dry-eye syndrome, for other toxicity like neovascular glaucoma, a plan comparison is warranted. Choice would depend on the prioritization of risks.
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Affiliation(s)
- Emmanuelle Fleury
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
- HollandPTC, Delft, The Netherlands
| | | | - Emine Kiliç
- Erasmus Medical Center, Department of Ophthalmology, Rotterdam, The Netherlands
- Erasmus Medical Center, Department of Clinical Genetics, Rotterdam, The Netherlands
| | - Maaike Milder
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
| | - Caroline van Rij
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
| | - Nicole Naus
- Erasmus Medical Center, Department of Ophthalmology, Rotterdam, The Netherlands
| | | | - Wilhelm den Toom
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
| | - Andras Zolnay
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
| | | | | | - Petra Trnková
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
- Medical University of Vienna, Department of Radiation Oncology, Vienna, Austria
| | - Mischa Hoogeman
- Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands
- HollandPTC, Delft, The Netherlands
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Shaikh S, Escribano-Rodriguez S, Radogna R, Kelleter L, Godden C, Warren M, Attree D, Saakyan R, Mortimer L, Corlett P, Warry A, Gosling A, Baker C, Poynter A, Kacperek A, Jolly S. Spread-out Bragg peak measurements using a compact quality assurance range calorimeter at the Clatterbridge cancer centre. Phys Med Biol 2024; 69:115015. [PMID: 38657625 DOI: 10.1088/1361-6560/ad42fd] [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: 02/13/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Objective.The superior dose conformity provided by proton therapy relative to conventional x-ray radiotherapy necessitates more rigorous quality assurance (QA) procedures to ensure optimal patient safety. Practically however, time-constraints prevent comprehensive measurements to be made of the proton range in water: a key parameter in ensuring accurate treatment delivery.Approach.A novel scintillator-based device for fast, accurate water-equivalent proton range QA measurements for ocular proton therapy is presented. Experiments were conducted using a compact detector prototype, the quality assurance range calorimeter (QuARC), at the Clatterbridge cancer centre (CCC) in Wirral, UK for the measurement of pristine and spread-out Bragg peaks (SOBPs). The QuARC uses a series of 14 optically-isolated 100 × 100 × 2.85 mm polystyrene scintillator sheets, read out by a series of photodiodes. The detector system is housed in a custom 3D-printed enclosure mounted directly to the nozzle and a numerical model was used to fit measured depth-light curves and correct for scintillator light quenching.Main results.Measurements of the pristine 60 MeV proton Bragg curve found the QuARC able to measure proton ranges accurate to 0.2 mm and reduced QA measurement times from several minutes down to a few seconds. A new framework of the quenching model was deployed to successfully fit depth-light curves of SOBPs with similar range accuracy.Significance.The speed, range accuracy and simplicity of the QuARC make the device a promising candidate for ocular proton range QA. Further work to investigate the performance of SOBP fitting at higher energies/greater depths is warranted.
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Affiliation(s)
- Saad Shaikh
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | | | | | - Laurent Kelleter
- Division of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Connor Godden
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Matthew Warren
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Derek Attree
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Ruben Saakyan
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Linda Mortimer
- Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
| | - Peter Corlett
- Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
| | - Alison Warry
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew Gosling
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Colin Baker
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew Poynter
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrzej Kacperek
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Simon Jolly
- Department of Physics and Astronomy, University College London, London, United Kingdom
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Guerra Liberal FDC, Parsons JL, McMahon SJ. Most DNA repair defects do not modify the relationship between relative biological effectiveness and linear energy transfer in CRISPR-edited cells. Med Phys 2024; 51:591-600. [PMID: 37753877 DOI: 10.1002/mp.16764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/15/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
BACKGROUND Cancer is a highly heterogeneous disease, driven by frequent genetic alterations which have significant effects on radiosensitivity. However, radiotherapy for a given cancer type is typically given with a standard dose determined from population-level trials. As a result, a proportion of patients are under- or over-dosed, reducing the clinical benefit of radiotherapy. Biological optimization would not only allow individual dose prescription but also a more efficient allocation of limited resources, such as proton and carbon ion therapy. Proton and ion radiotherapy offer an advantage over photons due to their elevated Relative Biological Effectiveness (RBE) resulting from their elevated Linear Energy Transfer (LET). Despite significant interest in optimizing LET by tailoring radiotherapy plans, RBE's genetic dependence remains unclear. PURPOSE The aim of this study is to better define the RBE/LET relationship in a panel of cell lines with different defects in DSB repair pathways, but otherwise identical biological features and genetic background to isolate these effects. METHODS Normal human cells (RPE1), genetically modified to introduce defects in DNA double-strand break (DSB) repair genes, ATM, BRCA1, DCLRE1C, LIG4, PRKDC and TP53, were used to map the RBE-LET relationship. Cell survival was measured with clonogenic assays after exposure to photons, protons (LET 1 and 12 keV/µm) and alpha particles (129 keV/µm). Gene knockout sensitizer enhancement ratio (SER) values were calculated as the ratio of the mean inactivation dose (MID) of wild-type cells to repair-deficient cells, and RBE values were calculated as the ratio of the MID of X-ray and particle irradiated cells. 53BP1 foci were used to quantify radiation-induced DSBs and their repair following irradiation. RESULTS Deletion of NHEJ genes had the greatest impact on photon sensitivity (ATM-/- SER = 2.0 and Lig4-/- SER = 1.8), with genes associated with HR having smaller effects (BRCA1-/- SER = 1.2). Wild-type cells showed RBEs of 1.1, 1.3, 5.0 for low- and high-LET protons and alpha particles respectively. SERs for different genes were independent of LET, apart from NHEJ knockouts which proved to be markedly hypersensitive across all tested LETs. Due to this hypersensitivity, the impact of high LET was reduced in cell models lacking the NHEJ repair pathway. HR-defective cells had moderately increased sensitivity across all tested LETs, but, notably, the contribution of HR pathway to survival appeared independent of LET. Analysis of 53BP1 foci shows that NHEJ-defective cells had the least DSB repair capacity after low LET exposure, and no visible repair after high LET exposure. HR-defective cells also had slower repair kinetics, but the impact of HR defects is not as severe as NHEJ defects. CONCLUSIONS DSB repair defects, particularly in NHEJ, conferred significant radiosensitivity across all LETs. This sensitization appeared independent of LET, suggesting that the contribution of different DNA repair pathways to survival does not depend on radiation quality.
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Affiliation(s)
| | - Jason L Parsons
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - Stephen J McMahon
- The Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
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Clausen M, Ruangchan S, Sotoudegan A, Resch AF, Knäusl B, Palmans H, Georg D. Small field proton irradiation for in vivo studies: Potential and limitations when adapting clinical infrastructure. Z Med Phys 2023; 33:542-551. [PMID: 36357294 PMCID: PMC10751703 DOI: 10.1016/j.zemedi.2022.10.002] [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: 05/12/2022] [Revised: 09/22/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE To evaluate the dosimetric accuracy for small field proton irradiation relevant for pre-clinical in vivo studies using clinical infrastructure and technology. In this context additional beam collimation and range reduction was implemented. METHODS AND MATERIALS The clinical proton beam line employing pencil beam scanning (PBS) was adapted for the irradiation of small fields at shallow depths. Cylindrical collimators with apertures of 15, 12, 7 and 5mm as well as two different range shifter types, placed at different distances relative to the target, were tested: a bolus range shifter (BRS) attached to the collimator and a clinical nozzle mounted range shifter (CRS) placed at a distance of 72cm from the collimator. The Monte Carlo (MC) based dose calculation engine implemented in the clinical treatment planning system (TPS) was commissioned for these two additional hardware components. The study was conducted with a phantom and cylindrical target sizes between 2 and 25mm in diameter following a dosimetric end-to-end test concept. RESULTS The setup with the CRS provided a uniform dose distribution across the target. An agreement of better than5% between the planned dose and the measurements was obtained for a target with 3mm diameter (collimator 5mm). A 2mm difference between the collimator and the target diameter (target being 2 mm smaller than the collimator) sufficed to cover the whole target with the planned dose in the setup with CRS. Using the BRS setup (target 8mm, collimator 12mm) resulted in non-homogeneous dose distributions, with a dose discrepancy of up to 10% between the planned and measured doses. CONCLUSION The clinical proton infrastructure with adequate beam line adaptations and a state-of-the-art TPS based on MC dose calculations enables small animal irradiations with a high dosimetric precision and accuracy for target sizes down to 3mm.
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Affiliation(s)
- Monika Clausen
- Division of Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria.
| | - Sirinya Ruangchan
- Division of Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria; Division of Therapeutic Radiation and Oncology, Department of Radiology, King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Arame Sotoudegan
- Division of Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria
| | - Andreas F Resch
- Division of Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria
| | - Barbara Knäusl
- Division of Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria
| | - Hugo Palmans
- Division of Medical Physics, MedAustron Ion Therapy Center, Wiener Neustadt, Austria; National Physical Laboratory, Teddington, United Kingdom
| | - Dietmar Georg
- Division of Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria; Division of Medical Physics, MedAustron Ion Therapy Center, Wiener Neustadt, Austria
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Hussain RN, Chiu A, Pittam B, Taktak A, Damato BE, Kacperek A, Errington D, Cauchi P, Chadha V, Connolly J, Salvi S, Rundle P, Cohen V, Arora A, Sagoo M, Bekir O, Kopsidas K, Heimann H. Proton beam radiotherapy for choroidal and ciliary body melanoma in the UK-national audit of referral patterns of 1084 cases. Eye (Lond) 2023; 37:1033-1036. [PMID: 35840716 PMCID: PMC10050435 DOI: 10.1038/s41433-022-02178-0] [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: 03/25/2022] [Revised: 07/03/2022] [Accepted: 07/07/2022] [Indexed: 11/08/2022] Open
Abstract
INTRODUCTION Proton beam therapy has been utilised for the treatment of uveal melanoma in the UK for over 30 years, undertaken under a single centre. In the UK, all ocular tumours are treated at one of four centres. We aimed to understand the variation in referral patterns to the UK proton service, capturing all uveal melanoma patients treated with this modality. METHODS Retrospective analysis of data regarding all patients treated at the Clatterbridge Proton service between January 2004 and December 2014. RESULTS A total of 1084 patients with uveal melanoma were treated. The mean age was 57 years (range 9-90 years), basal diameter of 11.5 mm (range 2.0-23.4 mm) and tumour thickness of 3.9 mm (range 0.1-15.4 mm). The majority were TNM stage I (39%) or II (36%). The distance to the optic nerve varied from 0 to 24.5 mm with 148 (14%) of patients having ciliary body involvement. There were variations in the phenotypic characteristic of the tumours treated with protons from different centres, with London referring predominantly small tumours at the posterior pole, Glasgow referring large tumours often at the ciliary body and Liverpool sending a mix of these groups. DISCUSSION In the UK, common indications for the use of proton treatment in uveal melanoma include small tumours in the posterior pole poorly accessible for plaque treatment (adjacent to the disc), tumours at the posterior pole affecting the fovea and large anterior tumours traditionally too large for brachytherapy. This is the first UK-wide audit enabling the capture of all patients treated at the single proton centre.
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Affiliation(s)
- R N Hussain
- Liverpool Ocular Oncology Centre, Royal Liverpool Hospital, Liverpool, L7 8XP, UK.
| | - A Chiu
- Liverpool Ocular Oncology Centre, Royal Liverpool Hospital, Liverpool, L7 8XP, UK
| | - B Pittam
- Liverpool Ocular Oncology Centre, Royal Liverpool Hospital, Liverpool, L7 8XP, UK
| | - A Taktak
- Department of Eye and Vision Science and Department of Biostatistics, University of Liverpool, Liverpool, L69 3GL, UK
| | - B E Damato
- Ocular Oncology Service, Moorfields Eye Hospital, London, EC1V 2PD, UK
- NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - A Kacperek
- University College London, London, WC1E 6BT, UK
| | - D Errington
- Clatterbridge Cancer Centre, Clatterbridge Road, Bebington, Wirral, CH63 4JY, UK
| | - P Cauchi
- Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, G12 0YN, UK
| | - V Chadha
- Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, G12 0YN, UK
| | - J Connolly
- Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, G12 0YN, UK
| | - S Salvi
- The National Sheffield Ocular Oncology Service, Royal Hallamshire Hospital, S10 2JF, Sheffield, UK
| | - P Rundle
- The National Sheffield Ocular Oncology Service, Royal Hallamshire Hospital, S10 2JF, Sheffield, UK
| | - V Cohen
- Ocular Oncology Service, Moorfields Eye Hospital, London, EC1V 2PD, UK
- NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - A Arora
- Ocular Oncology Service, Moorfields Eye Hospital, London, EC1V 2PD, UK
- NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - M Sagoo
- Ocular Oncology Service, Moorfields Eye Hospital, London, EC1V 2PD, UK
- NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - O Bekir
- Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, G12 0YN, UK
| | - K Kopsidas
- The National Sheffield Ocular Oncology Service, Royal Hallamshire Hospital, S10 2JF, Sheffield, UK
| | - H Heimann
- Liverpool Ocular Oncology Centre, Royal Liverpool Hospital, Liverpool, L7 8XP, UK
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Jaarsma-Coes MG, Klaassen L, Verbist BM, Vu TK, Klaver YL, Rodrigues MF, Nabarro C, Luyten GP, Rasch CR, van Herk M, Beenakker JWM. Inter-Observer Variability in MR-Based Target Volume Delineation of Uveal Melanoma. Adv Radiat Oncol 2022; 8:101149. [PMID: 36691449 PMCID: PMC9860418 DOI: 10.1016/j.adro.2022.101149] [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: 06/16/2022] [Accepted: 12/14/2022] [Indexed: 12/26/2022] Open
Abstract
Purpose Several efforts are being undertaken toward MRI-based treatment planning for ocular proton therapy for uveal melanoma (UM). The interobserver variability of the gross target volume (GTV) on magnetic resonance imaging (MRI) is one of the important parameters to design safety margins for a reliable treatment. Therefore, this study assessed the interobserver variation in GTV delineation of UM on MRI. Methods and Materials Six observers delineated the GTV in 10 different patients using the Big Brother contouring software. Patients were scanned at 3T MRI with a surface coil, and tumors were delineated separately on contrast enhanced 3DT1 (T1gd) and 3DT2-weighted scans with an isotropic acquisition resolution of 0.8 mm. Volume difference and overall local variation (median standard deviation of the distance between the delineated contours and the median contour) were analyzed for each GTV. Additionally, the local variation was analyzed for 4 interfaces: sclera, vitreous, retinal detachment, and tumor-choroid interface. Results The average GTV was significantly larger on T1gd (0.57cm3) compared with T2 (0.51cm3, P = .01). A not significant higher interobserver variation was found on T1gd (0.41 mm) compared with T2 (0.35 mm). The largest variations were found at the tumor-choroid interface due to peritumoral enhancement (T1gd, 0.62 mm; T2, 0.52 mm). As a result, a larger part of this tumor-choroid interface appeared to be included on T1gd-based GTVs compared with T2, explaining the smaller volumes on T2. Conclusions The interobserver variation of 0.4 mm on MRI are low with respect to the voxel size of 0.8 mm, enabling small treatment margins. We recommend delineation based on the T1gd-weighted scans, as choroidal tumor extensions might be missed.
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Affiliation(s)
- Myriam G. Jaarsma-Coes
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands,Leiden University Medical Center, Radiology, Leiden, Netherlands
| | - Lisa Klaassen
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands,Leiden University Medical Center, Radiology, Leiden, Netherlands
| | - Berit M. Verbist
- Leiden University Medical Center, Radiology, Leiden, Netherlands
| | - T.H. Khanh Vu
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands
| | - Yvonne L.B. Klaver
- HollandPTC, Radiation oncology, Delft, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands
| | - Myra F. Rodrigues
- HollandPTC, Radiation oncology, Delft, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands
| | - Claire Nabarro
- Leiden University Medical Center, Radiology, Leiden, Netherlands
| | | | - Coen R.N. Rasch
- HollandPTC, Radiation oncology, Delft, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands
| | - Marcel van Herk
- Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom
| | - Jan-Willem M. Beenakker
- Leiden University Medical Center, Ophthalmology, Leiden, Netherlands,Leiden University Medical Center, Radiology, Leiden, Netherlands,Leiden University Medical Center, Radiation Oncology, Leiden, Netherlands,Corresponding author: Jan-Willem M. Beenakker
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Fleury E, Trnková P, Spruijt K, Herault J, Lebbink F, Heufelder J, Hrbacek J, Horwacik T, Kajdrowicz T, Denker A, Gerard A, Hofverberg P, Mamalui M, Slopsema R, Pignol J, Hoogeman M. Characterization of the HollandPTC proton therapy beamline dedicated to uveal melanoma treatment and an interinstitutional comparison. Med Phys 2021; 48:4506-4522. [PMID: 34091930 PMCID: PMC8457201 DOI: 10.1002/mp.15024] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/08/2021] [Accepted: 05/25/2021] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Eye-dedicated proton therapy (PT) facilities are used to treat malignant intraocular lesions, especially uveal melanoma (UM). The first commercial ocular PT beamline from Varian was installed in the Netherlands. In this work, the conceptual design of the new eyeline is presented. In addition, a comprehensive comparison against five PT centers with dedicated ocular beamlines is performed, and the clinical impact of the identified differences is analyzed. MATERIAL/METHODS The HollandPTC eyeline was characterized. Four centers in Europe and one in the United States joined the study. All centers use a cyclotron for proton beam generation and an eye-dedicated nozzle. Differences among the chosen ocular beamlines were in the design of the nozzle, nominal energy, and energy spectrum. The following parameters were collected for all centers: technical characteristics and a set of distal, proximal, and lateral region measurements. The measurements were performed with detectors available in-house at each institution. The institutions followed the International Atomic Energy Agency (IAEA) Technical Report Series (TRS)-398 Code of Practice for absolute dose measurement, and the IAEA TRS-398 Code of Practice, its modified version or International Commission on Radiation Units and Measurements Report No. 78 for spread-out Bragg peak normalization. Energy spreads of the pristine Bragg peaks were obtained with Monte Carlo simulations using Geant4. Seven tumor-specific case scenarios were simulated to evaluate the clinical impact among centers: small, medium, and large UM, located either anteriorly, at the equator, or posteriorly within the eye. Differences in the depth dose distributions were calculated. RESULTS A pristine Bragg peak of HollandPTC eyeline corresponded to the constant energy of 75 MeV (maximal range 3.97 g/cm2 in water) with an energy spread of 1.10 MeV. The pristine Bragg peaks for the five participating centers varied from 62.50 to 104.50 MeV with an energy spread variation between 0.10 and 0.70 MeV. Differences in the average distal fall-offs and lateral penumbrae (LPs) (over the complete set of clinically available beam modulations) among all centers were up to 0.25 g/cm2 , and 0.80 mm, respectively. Average distal fall-offs of the HollandPTC eyeline were 0.20 g/cm2 , and LPs were between 1.50 and 2.15 mm from proximal to distal regions, respectively. Treatment time, around 60 s, was comparable among all centers. The virtual source-to-axis distance of 120 cm at HollandPTC was shorter than for the five participating centers (range: 165-350 cm). Simulated depth dose distributions demonstrated the impact of the different beamline characteristics among institutions. The largest difference was observed for a small UM located at the posterior pole, where a proximal dose between two extreme centers was up to 20%. CONCLUSIONS HollandPTC eyeline specifications are in accordance with five other ocular PT beamlines. Similar clinical concepts can be applied to expect the same high local tumor control. Dosimetrical properties among the six institutions induce most likely differences in ocular radiation-related toxicities. This interinstitutional comparison could support further research on ocular post-PT complications. Finally, the findings reported in this study could be used to define dosimetrical guidelines for ocular PT to unify the concepts among institutions.
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Affiliation(s)
- Emmanuelle Fleury
- Department of RadiotherapyErasmus MC Cancer Institute, University Medical Center RotterdamThe Netherlands
- Holland Proton Therapy CenterDelftThe Netherlands
| | - Petra Trnková
- Department of RadiotherapyErasmus MC Cancer Institute, University Medical Center RotterdamThe Netherlands
- Departement of Radiation OncologyMedical University of ViennaViennaAustria
| | - Kees Spruijt
- Holland Proton Therapy CenterDelftThe Netherlands
| | - Joël Herault
- Departement of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | | | - Jens Heufelder
- Helmholtz‐Zentrum Berlin für Materialien und EnergieBerlinGermany
- Department of OphthalmologyCharité ‐ Universitätsmedizin BerlinBerlinGermany
| | - Jan Hrbacek
- Paul Scherrer Institute Center for Proton TherapyVilligenSwitzerland
| | - Tomasz Horwacik
- Institute of Nuclear PhysicsPolish Academy of SciencesKrakówPoland
| | | | - Andrea Denker
- Helmholtz‐Zentrum Berlin für Materialien und EnergieBerlinGermany
| | - Anaïs Gerard
- Departement of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | - Petter Hofverberg
- Departement of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | - Maria Mamalui
- Department of Radiation OncologyUniversity of FloridaGainesvilleFloridaUSA
| | - Roelf Slopsema
- Department of Radiation OncologyEmory Proton Therapy CenterAtlantaGeorgiaUSA
| | | | - Mischa Hoogeman
- Department of RadiotherapyErasmus MC Cancer Institute, University Medical Center RotterdamThe Netherlands
- Holland Proton Therapy CenterDelftThe Netherlands
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9
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Fleury E, Trnková P, Erdal E, Hassan M, Stoel B, Jaarma‐Coes M, Luyten G, Herault J, Webb A, Beenakker J, Pignol J, Hoogeman M. Three-dimensional MRI-based treatment planning approach for non-invasive ocular proton therapy. Med Phys 2021; 48:1315-1326. [PMID: 33336379 PMCID: PMC7986198 DOI: 10.1002/mp.14665] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 10/05/2020] [Accepted: 11/30/2020] [Indexed: 12/23/2022] Open
Abstract
PURPOSE To develop a high-resolution three-dimensional (3D) magnetic resonance imaging (MRI)-based treatment planning approach for uveal melanomas (UM) in proton therapy. MATERIALS/METHODS For eight patients with UM, a segmentation of the gross tumor volume (GTV) and organs-at-risk (OARs) was performed on T1- and T2-weighted 7 Tesla MRI image data to reconstruct the patient MR-eye. An extended contour was defined with a 2.5-mm isotropic margin derived from the GTV. A broad beam algorithm, which we have called πDose, was implemented to calculate relative proton absorbed doses to the ipsilateral OARs. Clinically favorable gazing angles of the treated eye were assessed by calculating a global weighted-sum objective function, which set penalties for OARs and extreme gazing angles. An optimizer, which we have named OPT'im-Eye-Tool, was developed to tune the parameters of the functions for sparing critical-OARs. RESULTS In total, 441 gazing angles were simulated for every patient. Target coverage including margins was achieved in all the cases (V95% > 95%). Over the whole gazing angles solutions space, maximum dose (Dmax ) to the optic nerve and the macula, and mean doses (Dmean ) to the lens, the ciliary body and the sclera were calculated. A forward optimization was applied by OPT'im-Eye-Tool in three different prioritizations: iso-weighted, optic nerve prioritized, and macula prioritized. In each, the function values were depicted in a selection tool to select the optimal gazing angle(s). For example, patient 4 had a T2 equatorial tumor. The optimization applied for the straight gazing angle resulted in objective function values of 0.46 (iso-weighted situation), 0.90 (optic nerve prioritization) and 0.08 (macula prioritization) demonstrating the impact of that angle in different clinical approaches. CONCLUSIONS The feasibility and suitability of a 3D MRI-based treatment planning approach have been successfully tested on a cohort of eight patients diagnosed with UM. Moreover, a gaze-angle trade-off dose optimization with respect to OARs sparing has been developed. Further validation of the whole treatment process is the next step in the goal to achieve both a non-invasive and a personalized proton therapy treatment.
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Affiliation(s)
- E. Fleury
- Department of Radiation OncologyErasmus Medical CenterRotterdamThe Netherlands
- Department of Radiation OncologyHollandPTCDelftThe Netherlands
| | - P. Trnková
- Department of Radiation OncologyErasmus Medical CenterRotterdamThe Netherlands
- Department of Radiation OncologyHollandPTCDelftThe Netherlands
| | - E. Erdal
- Department of Radiation OncologyHollandPTCDelftThe Netherlands
| | - M. Hassan
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - B. Stoel
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - M. Jaarma‐Coes
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - G. Luyten
- Department of OphthalmologyLeiden University Medical CenterLeidenThe Netherlands
| | - J. Herault
- Department of Radiation OncologyCentre Antoine LacassagneNiceFrance
| | - A. Webb
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - J.‐W. Beenakker
- Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
- Department of OphthalmologyLeiden University Medical CenterLeidenThe Netherlands
| | - J.‐P. Pignol
- Department of Radiation OncologyDalhousie UniversityHalifaxCanada
| | - M. Hoogeman
- Department of Radiation OncologyErasmus Medical CenterRotterdamThe Netherlands
- Department of Radiation OncologyHollandPTCDelftThe Netherlands
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10
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Yap J, Resta-López J, Kacperek A, Schnuerer R, Jolly S, Boogert S, Welsch C. Beam characterisation studies of the 62 MeV proton therapy beamline at the Clatterbridge Cancer Centre. Phys Med 2020; 77:108-120. [DOI: 10.1016/j.ejmp.2020.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 07/15/2020] [Accepted: 08/03/2020] [Indexed: 10/23/2022] Open
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Via R, Pella A, Romanò F, Fassi A, Ricotti R, Tagaste B, Vai A, Mastella E, Rosaria Fiore M, Valvo F, Ciocca M, Baroni G. A platform for patient positioning and motion monitoring in ocular proton therapy with a non-dedicated beamline. Phys Med 2019; 59:55-63. [PMID: 30928066 DOI: 10.1016/j.ejmp.2019.02.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 02/25/2019] [Accepted: 02/25/2019] [Indexed: 11/08/2022] Open
Abstract
PURPOSE At Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy) ocular proton therapy (OPT) is delivered using a non-dedicated beamline. This paper describes the novel clinical workflow as well as technologies and methods adopted to achieve accurate target positioning and verification during ocular proton therapy at CNAO. METHOD The OPT clinical protocol at CNAO prescribes a treatment simulation and a delivery phase, performed in the CT and treatment rooms, respectively. The patient gaze direction is controlled and monitored during the entire workflow by means of an eye tracking system (ETS) featuring two optical cameras and an embedded fixation diode light. Thus, the accurate alignment of the fixation light provided to the patient to the prescribed gazed direction is required for an effective treatment. As such, a technological platform based on active robotic manipulators and IR optical tracking-based guidance was developed and tested. The effectiveness of patient positioning strategies was evaluated on a clinical dataset comprising twenty patients treated at CNAO. RESULTS According to experimental testing, the developed technologies guarantee uncertainties lower than one degree in gaze direction definition by means of ETS-guided positioning. Patient positioning and monitoring strategies during treatment effectively mitigated set-up uncertainties and exhibited sub-millimetric accuracy in radiopaque markers alignment. CONCLUSION Ocular proton therapy is currently delivered at CNAO with a non-dedicated beamline. The technologies developed for patient positioning and motion monitoring have proven to be compliant with the high geometrical accuracy required for the treatment of intraocular tumors.
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Affiliation(s)
- Riccardo Via
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano 20133, Italy.
| | - Andrea Pella
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | | | - Aurora Fassi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano 20133, Italy
| | - Rosalinda Ricotti
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | - Barbara Tagaste
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | - Alessandro Vai
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | - Edoardo Mastella
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | | | - Francesca Valvo
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | - Mario Ciocca
- Centro Nazionale di Adroterapia Oncologica Foundation, Pavia 27100, Italy
| | - Guido Baroni
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano 20133, Italy
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Ciocca M, Magro G, Mastella E, Mairani A, Mirandola A, Molinelli S, Russo S, Vai A, Fiore MR, Mosci C, Valvo F, Via R, Baroni G, Orecchia R. Design and commissioning of the non-dedicated scanning proton beamline for ocular treatment at the synchrotron-based CNAO facility. Med Phys 2019; 46:1852-1862. [PMID: 30659616 DOI: 10.1002/mp.13389] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 12/11/2018] [Accepted: 01/09/2019] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Only few centers worldwide treat intraocular tumors with proton therapy, all of them with a dedicated beamline, except in one case in the USA. The Italian National Center for Oncological Hadrontherapy (CNAO) is a synchrotron-based hadrontherapy facility equipped with fixed beamlines and pencil beam scanning modality. Recently, a general-purpose horizontal proton beamline was adapted to treat also ocular diseases. In this work, the conceptual design and main dosimetric properties of this new proton eyeline are presented. METHODS A 28 mm thick water-equivalent range shifter (RS) was placed along the proton beamline to shift the minimum beam penetration at shallower depths. FLUKA Monte Carlo (MC) simulations were performed to optimize the position of the RS and patient-specific collimator, in order to achieve sharp lateral dose gradients. Lateral dose profiles were then measured with radiochromic EBT3 films to evaluate the dose uniformity and lateral penumbra width at several depths. Different beam scanning patterns were tested. Discrete energy levels with 1 mm water-equivalent step within the whole ocular energy range (62.7-89.8 MeV) were used, while fine adjustment of beam range was achieved using thin polymethylmethacrylate additional sheets. Depth-dose distributions (DDDs) were measured with the Peakfinder system. Monoenergetic beam weights to achieve flat spread-out Bragg Peaks (SOBPs) were numerically determined. Absorbed dose to water under reference conditions was measured with an Advanced Markus chamber, following International Atomic Energy Agency (IAEA) Technical Report Series (TRS)-398 Code of Practice. Neutron dose at the contralateral eye was evaluated with passive bubble dosimeters. RESULTS Monte Carlo simulations and experimental results confirmed that maximizing the air gap between RS and aperture reduces the lateral dose penumbra width of the collimated beam and increases the field transversal dose homogeneity. Therefore, RS and brass collimator were placed at about 98 cm (upstream of the beam monitors) and 7 cm from the isocenter, respectively. The lateral 80%-20% penumbra at middle-SOBP ranged between 1.4 and 1.7 mm depending on field size, while 90%-10% distal fall-off of the DDDs ranged between 1.0 and 1.5 mm, as a function of range. Such values are comparable to those reported for most existing eye-dedicated facilities. Measured SOBP doses were in very good agreement with MC simulations. Mean neutron dose at the contralateral eye was 68 μSv/Gy. Beam delivery time, for 60 Gy relative biological effectiveness (RBE) prescription dose in four fractions, was around 3 min per session. CONCLUSIONS Our adapted scanning proton beamline satisfied the requirements for intraocular tumor treatment. The first ocular treatment was delivered in August 2016 and more than 100 patients successfully completed their treatment in these 2 yr.
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Affiliation(s)
- Mario Ciocca
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy
| | - Giuseppe Magro
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy
| | | | - Andrea Mairani
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy
| | | | | | - Stefania Russo
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy
| | - Alessandro Vai
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy
| | | | - Carlo Mosci
- Ente Ospedaliero Ospedali Galliera, via Mura delle Cappuccine 14, 16128, Genova, Italy
| | | | - Riccardo Via
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Guido Baroni
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy.,Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, piazza Leonardo da Vinci 32, 20133, Milano, Italy
| | - Roberto Orecchia
- Fondazione CNAO, strada Campeggi 53, 27100, Pavia, Italy.,Istituto Europeo di Oncologia, via Ripamonti 435, 20100, Milano, Italy
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13
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Slopsema RL, Mamalui M, Bolling J, Flampouri S, Yeung D, Li Z, Rutenberg MS, Dagan R. Can CT imaging improve targeting accuracy in clip-based proton therapy of ocular melanoma? Phys Med Biol 2019; 64:035010. [PMID: 30566923 DOI: 10.1088/1361-6560/aaf9c9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To evaluate the benefit of adding CT imaging to the simulation process of clip-based proton therapy of ocular melanomas. For thirty ocular melanoma cases, the clip position in the eye model was determined based on orthogonal radiographs as well as on a CT image set. The geometrical shift of the clips between the standard simulation process and standard simulation process with addition of CT imaging (CT-guided) was determined. The dosimetric impact was evaluated by developing treatment plans based on both the standard-process model and the CT-guided model. In 40% of the studied cases, the difference in clip position between eye models created with and without CT was less than 0.5 mm. This difference was more than 1 mm in 17% of cases. The dosimetric impact of shifts below 1 mm was low because these shifts did not exceed the planning margins. For the four cases with a shift of more than 1 mm a reduction in target coverage (ΔV99%) of -3% to -6% was observed. Changes in macula and optic-disc mean dose of up to 16% and 35% of the prescribed dose were seen when these structures abutted the target. Adding CT imaging to the simulation process is beneficial in select cases where discrepancies between the eye model and ophthalmology measurements occur or where a critical structure is located close to the target and improved localization accuracy is wanted. For the majority of patients, addition of CT imaging does not result in quantifiable changes in dosimetry. Nevertheless, CT imaging is a valuable tool in the quality control of the modeling and treatment-planning process of clip-based eye treatments.
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Affiliation(s)
- R L Slopsema
- University of Florida Health Proton Therapy Institute, 2015 North Jefferson Street, Jacksonville, FL 32206, United States of America. Author to whom any correspondence should be addressed
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14
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Hoehr C, Lindsay C, Beaudry J, Penner C, Strgar V, Lee R, Duzenli C. Characterization of the exradin W1 plastic scintillation detector for small field applications in proton therapy. Phys Med Biol 2018; 63:095016. [PMID: 29634488 DOI: 10.1088/1361-6560/aabd2d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Accurate dosimetry in small field proton therapy is challenging, particularly for applications such as ocular therapy, and suitable detectors for this purpose are sought. The Exradin W1 plastic scintillating fibre detector is known to out-perform most other detectors for determining relative dose factors for small megavoltage photon beams used in radiotherapy but its potential in small proton beams has been relatively unexplored in the literature. The 1 mm diameter cylindrical geometry and near water equivalence of the W1 makes it an attractive alternative to other detectors. This study examines the dosimetric performance of the W1 in a 74 MeV proton therapy beam with particular focus on detector response characteristics relevant to relative dose measurement in small fields suitable for ocular therapy. Quenching of the scintillation signal is characterized and demonstrated not to impede relative dose measurements at a fixed depth. The background cable-only (Čerenkov and radio-fluorescence) signal is 4 orders of magnitude less than the scintillation signal, greatly simplifying relative dose measurements. Comparison with other detectors and Monte Carlo simulations indicate that the W1 is useful for measuring relative dose factors for field sizes down to 5 mm diameter and shallow spread out Bragg peaks down to 6 mm in depth.
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Affiliation(s)
- C Hoehr
- TRIUMF, 4004 Wesbrook Mall, Vancouver, Canada. University of Victoria, Victoria, Canada
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15
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Via R, Hennings F, Fattori G, Fassi A, Pica A, Lomax A, Weber DC, Baroni G, Hrbacek J. Noninvasive eye localization in ocular proton therapy through optical eye tracking: A proof of concept. Med Phys 2018; 45:2186-2194. [DOI: 10.1002/mp.12841] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/16/2018] [Accepted: 02/17/2018] [Indexed: 11/05/2022] Open
Affiliation(s)
- Riccardo Via
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano 20133 Italy
| | - Fabian Hennings
- Center for Proton Therapy; Paul Scherrer Institut; Villigen PSI 5232 Switzerland
| | - Giovanni Fattori
- Center for Proton Therapy; Paul Scherrer Institut; Villigen PSI 5232 Switzerland
| | - Aurora Fassi
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano 20133 Italy
| | - Alessia Pica
- Center for Proton Therapy; Paul Scherrer Institut; Villigen PSI 5232 Switzerland
| | - Antony Lomax
- Center for Proton Therapy; Paul Scherrer Institut; Villigen PSI 5232 Switzerland
- Department of Physics; ETH-Hönggerberg; Zurich 8093 Switzerland
| | - Damien Charles Weber
- Center for Proton Therapy; Paul Scherrer Institut; Villigen PSI 5232 Switzerland
- Radiation Oncology Department; Inselspital Universitätsspital Bern; Bern 3010 Switzerland
| | - Guido Baroni
- Dipartimento di Elettronica, Informazione e Bioingegneria; Politecnico di Milano; Milano 20133 Italy
- CNAO Centro Nazionale di Adroterapia Oncologica; Pavia 27100 Italy
| | - Jan Hrbacek
- Center for Proton Therapy; Paul Scherrer Institut; Villigen PSI 5232 Switzerland
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16
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Carter RJ, Nickson CM, Thompson JM, Kacperek A, Hill MA, Parsons JL. Complex DNA Damage Induced by High Linear Energy Transfer Alpha-Particles and Protons Triggers a Specific Cellular DNA Damage Response. Int J Radiat Oncol Biol Phys 2017; 100:776-784. [PMID: 29413288 PMCID: PMC5796827 DOI: 10.1016/j.ijrobp.2017.11.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/27/2017] [Accepted: 11/07/2017] [Indexed: 12/31/2022]
Abstract
Purpose To investigate the precise mechanism of recognition and processing of ionizing radiation (IR)-induced complex DNA damage (CDD), where two or more DNA lesions are in close proximity, in cellular DNA which is packaged with histones to form chromatin. Methods and Materials HeLa and oropharyngeal squamous cell carcinoma (UMSCC74A and UMSCC6) cells were irradiated with high linear energy transfer (LET) α-particles or protons, versus low-LET protons and X rays. At various time points after irradiation, site-specific histone post-translational modifications were analyzed by quantitative Western blotting; DNA damage and repair were measured by different versions of the comet assay; and cell survival was determined using clonogenic assays. Results Site-specific histone post-translational modifications after low- and high-LET radiation, particularly proton irradiation, were screened, aiming to identify those responsive to CDD. We demonstrate that histone H2B ubiquitylated on lysine 120 (H2Bub) is specifically induced several hours after irradiation in response to high-LET α-particles and protons but not by low-LET protons or X rays/γ-radiation. This is associated with increased levels of CDD, which contributes to decreased cell survival. We further discovered that modulation of H2Bub is under the control of two E3 ubiquitin ligases, MSL2 and RNF20/RNF40 complex, whose depletion leads to defective processing and further persistence of CDD, and to additional decreased cell survival after irradiation. Conclusion This study demonstrates that the signaling and repair of CDD, particularly induced by high-LET IR is co-ordinated through the specific induction of H2Bub catalyzed by MSL2 and RNF20/40, a mechanism that contributes significantly to cell survival after irradiation.
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Affiliation(s)
- Rachel J Carter
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, United Kingdom
| | - Catherine M Nickson
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, United Kingdom
| | - James M Thompson
- Gray Laboratories, Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Andrzej Kacperek
- The National Eye Proton Therapy Centre, The Clatterbridge Cancer Centre NHS Foundation Trust, Bebington, United Kingdom
| | - Mark A Hill
- Gray Laboratories, Cancer Research UK/Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
| | - Jason L Parsons
- Cancer Research Centre, Department of Molecular and Clinical Cancer Medicine, University of Liverpool, United Kingdom.
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Almurayshid M, Helo Y, Kacperek A, Griffiths J, Hebden J, Gibson A. Quality assurance in proton beam therapy using a plastic scintillator and a commercially available digital camera. J Appl Clin Med Phys 2017; 18:210-219. [PMID: 28755419 PMCID: PMC5874858 DOI: 10.1002/acm2.12143] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/14/2017] [Accepted: 06/14/2017] [Indexed: 11/21/2022] Open
Abstract
Purpose In this article, we evaluate a plastic scintillation detector system for quality assurance in proton therapy using a BC‐408 plastic scintillator, a commercial camera, and a computer. Methods The basic characteristics of the system were assessed in a series of proton irradiations. The reproducibility and response to changes of dose, dose‐rate, and proton energy were determined. Photographs of the scintillation light distributions were acquired, and compared with Geant4 Monte Carlo simulations and with depth‐dose curves measured with an ionization chamber. A quenching effect was observed at the Bragg peak of the 60 MeV proton beam where less light was produced than expected. We developed an approach using Birks equation to correct for this quenching. We simulated the linear energy transfer (LET) as a function of depth in Geant4 and found Birks constant by comparing the calculated LET and measured scintillation light distribution. We then used the derived value of Birks constant to correct the measured scintillation light distribution for quenching using Geant4. Results The corrected light output from the scintillator increased linearly with dose. The system is stable and offers short‐term reproducibility to within 0.80%. No dose rate dependency was observed in this work. Conclusions This approach offers an effective way to correct for quenching, and could provide a method for rapid, convenient, routine quality assurance for clinical proton beams. Furthermore, the system has the advantage of providing 2D visualization of individual radiation fields, with potential application for quality assurance of complex, time‐varying fields.
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Affiliation(s)
- Mansour Almurayshid
- University College London, Medical Physics and Biomedical Engineering, London, UK
| | - Yusuf Helo
- University College London, Medical Physics and Biomedical Engineering, London, UK
| | - Andrzej Kacperek
- Clatterbridge Cancer Centre, Medical Physics and Biomedical Engineering, London, UK
| | - Jennifer Griffiths
- University College London, Medical Physics and Biomedical Engineering, London, UK
| | - Jem Hebden
- University College London, Medical Physics and Biomedical Engineering, London, UK
| | - Adam Gibson
- University College London, Medical Physics and Biomedical Engineering, London, UK
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Lourenço A, Shipley D, Wellock N, Thomas R, Bouchard H, Kacperek A, Fracchiolla F, Lorentini S, Schwarz M, MacDougall N, Royle G, Palmans H. Evaluation of the water-equivalence of plastic materials in low- and high-energy clinical proton beams. Phys Med Biol 2017; 62:3883-3901. [PMID: 28319031 DOI: 10.1088/1361-6560/aa67d4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The aim of this work was to evaluate the water-equivalence of new trial plastics designed specifically for light-ion beam dosimetry as well as commercially available plastics in clinical proton beams. The water-equivalence of materials was tested by computing a plastic-to-water conversion factor, [Formula: see text]. Trial materials were characterized experimentally in 60 MeV and 226 MeV un-modulated proton beams and the results were compared with Monte Carlo simulations using the FLUKA code. For the high-energy beam, a comparison between the trial plastics and various commercial plastics was also performed using FLUKA and Geant4 Monte Carlo codes. Experimental information was obtained from laterally integrated depth-dose ionization chamber measurements in water, with and without plastic slabs with variable thicknesses in front of the water phantom. Fluence correction factors, [Formula: see text], between water and various materials were also derived using the Monte Carlo method. For the 60 MeV proton beam, [Formula: see text] and [Formula: see text] factors were within 1% from unity for all trial plastics. For the 226 MeV proton beam, experimental [Formula: see text] values deviated from unity by a maximum of about 1% for the three trial plastics and experimental results showed no advantage regarding which of the plastics was the most equivalent to water. Different magnitudes of corrections were found between Geant4 and FLUKA for the various materials due mainly to the use of different nonelastic nuclear data. Nevertheless, for the 226 MeV proton beam, [Formula: see text] correction factors were within 2% from unity for all the materials. Considering the results from the two Monte Carlo codes, PMMA and trial plastic #3 had the smallest [Formula: see text] values, where maximum deviations from unity were 1%, however, PMMA range differed by 16% from that of water. Overall, [Formula: see text] factors were deviating more from unity than [Formula: see text] factors and could amount to a few percent for some materials.
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Affiliation(s)
- A Lourenço
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom. Division of Acoustics and Ionising Radiation, National Physical Laboratory, Teddington TW11 0LW, United Kingdom
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Renaud J, Rossomme S, Sarfehnia A, Vynckier S, Palmans H, Kacperek A, Seuntjens J. Development and application of a water calorimeter for the absolute dosimetry of short-range particle beams. Phys Med Biol 2016; 61:6602-6619. [DOI: 10.1088/0031-9155/61/18/6602] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lourenço A, Thomas R, Bouchard H, Kacperek A, Vondracek V, Royle G, Palmans H. Experimental and Monte Carlo studies of fluence corrections for graphite calorimetry in low- and high-energy clinical proton beams. Med Phys 2016; 43:4122. [DOI: 10.1118/1.4951733] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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The influence of physical wedges on penumbra and in-field dose uniformity in ocular proton beams. Phys Med 2016; 32:612-7. [PMID: 26988936 DOI: 10.1016/j.ejmp.2016.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/04/2015] [Accepted: 01/02/2016] [Indexed: 11/20/2022] Open
Abstract
A physical wedge may be partially introduced into a proton beam when treating ocular tumours in order to improve dose conformity to the distal border of the tumour and spare the optic nerve. Two unwanted effects of this are observed: a predictable broadening of the beam penumbra on the wedged side of the field and, less predictably, an increase in dose within the field along a relatively narrow volume beneath the edge (toe) of the wedge, as a result of small-angle proton scatter. Monte Carlo simulations using MCNPX and direct measurements with radiochromic (GAFCHROMIC(®) EBT2) film were performed to quantify these effects for aluminium wedges in a 60 MeV proton beam as a function of wedge angle and position of the wedge relative to the patient. For extreme wedge angles (60° in eye tissue) and large wedge-to-patient distances (70 mm in this context), the 90-10% beam penumbra increased from 1.9 mm to 9.1 mm. In-field dose increases from small-angle proton scatter were found to contribute up to 21% additional dose, persisting along almost the full depth of the spread-out-Bragg peak. Profile broadening and in-field dose enhancement are both minimised by placing the wedge as close as possible to the patient. Use of lower atomic number wedge materials such as PMMA reduce the magnitude of both effects as a result of a reduced mean scattering angle per unit energy loss; however, their larger physical size and greater variation in density are undesirable.
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Nichiporov D, Coutinho L, Klyachko AV. Characterization of a GEM-based scintillation detector with He–CF4gas mixture in clinical proton beams. Phys Med Biol 2016; 61:2972-90. [DOI: 10.1088/0031-9155/61/8/2972] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rasouli FS, Farhad Masoudi S, Keshazare S, Jette D. Effect of elemental compositions on Monte Carlo dose calculations in proton therapy of eye tumors. Radiat Phys Chem Oxf Engl 1993 2015. [DOI: 10.1016/j.radphyschem.2015.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Chaudhary P, Marshall TI, Currell FJ, Kacperek A, Schettino G, Prise KM. Variations in the Processing of DNA Double-Strand Breaks Along 60-MeV Therapeutic Proton Beams. Int J Radiat Oncol Biol Phys 2015; 95:86-94. [PMID: 26452569 PMCID: PMC4840231 DOI: 10.1016/j.ijrobp.2015.07.2279] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 01/27/2016] [Accepted: 02/05/2016] [Indexed: 12/25/2022]
Abstract
Purpose To investigate the variations in induction and repair of DNA damage along the proton path, after a previous report on the increasing biological effectiveness along clinically modulated 60-MeV proton beams. Methods and Materials Human skin fibroblast (AG01522) cells were irradiated along a monoenergetic and a modulated spread-out Bragg peak (SOBP) proton beam used for treating ocular melanoma at the Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral, Liverpool, United Kingdom. The DNA damage response was studied using the 53BP1 foci formation assay. The linear energy transfer (LET) dependence was studied by irradiating the cells at depths corresponding to entrance, proximal, middle, and distal positions of SOBP and the entrance and peak position for the pristine beam. Results A significant amount of persistent foci was observed at the distal end of the SOBP, suggesting complex residual DNA double-strand break damage induction corresponding to the highest LET values achievable by modulated proton beams. Unlike the directly irradiated, medium-sharing bystander cells did not show any significant increase in residual foci. Conclusions The DNA damage response along the proton beam path was similar to the response of X rays, confirming the low-LET quality of the proton exposure. However, at the distal end of SOBP our data indicate an increased complexity of DNA lesions and slower repair kinetics. A lack of significant induction of 53BP1 foci in the bystander cells suggests a minor role of cell signaling for DNA damage under these conditions.
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Affiliation(s)
- Pankaj Chaudhary
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, United Kingdom
| | - Thomas I Marshall
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, United Kingdom
| | - Frederick J Currell
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, United Kingdom; Centre for Plasma Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast, United Kingdom
| | - Andrzej Kacperek
- Douglas Cyclotron, Clatterbridge Cancer Centre, Bebbington, Wirral, United Kingdom
| | | | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, United Kingdom
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Degiovanni A, Amaldi U. History of hadron therapy accelerators. Phys Med 2015; 31:322-32. [PMID: 25812487 DOI: 10.1016/j.ejmp.2015.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/11/2022] Open
Abstract
In the last 60 years, hadron therapy has made great advances passing from a stage of pure research to a well-established treatment modality for solid tumours. In this paper the history of hadron therapy accelerators is reviewed, starting from the first cyclotrons used in the thirties for neutron therapy and passing to more modern and flexible machines used nowadays. The technical developments have been accompanied by clinical studies that allowed the selection of the tumours which are more sensitive to this type of radiotherapy. This paper aims at giving a review of the origin and the present status of hadron therapy accelerators, describing the technological basis and the continuous development of this application to medicine of instruments developed for fundamental science. At the end the present challenges are reviewed.
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Affiliation(s)
| | - Ugo Amaldi
- TERA Foundation, Via Puccini 11, 28100 Novara, Italy.
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Helo Y, Kacperek A, Rosenberg I, Royle G, Gibson AP. The physics of Cerenkov light production during proton therapy. Phys Med Biol 2014; 59:7107-23. [DOI: 10.1088/0031-9155/59/23/7107] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Proton beam therapy for presumed and confirmed iris melanomas: a review of 36 cases. Graefes Arch Clin Exp Ophthalmol 2014; 252:1515-21. [PMID: 25038910 DOI: 10.1007/s00417-014-2735-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/23/2014] [Accepted: 07/02/2014] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND To report the clinical features and outcomes of iris melanomas treated by proton beam therapy. MATERIALS AND METHODS A retrospective study was conducted at the Croix-Rousse University Hospital of Lyon, Department of Ophthalmology, in 36 patients treated by proton beam therapy for presumed (n = 29) and confirmed (n = 7) iris melanomas between July 1997 and October 2010. Ciliary body melanomas with iris involvement were excluded. The patients' mean age was 54.4 years (range, 22-82 years). The average tumor diameter was 3.8 mm (range, 2.5-8.0). The iridocorneal angle was invaded by the tumor in 47% of cases (n = 17), the ciliary body in 17% of cases (n = 6), and the sclera in 3% (n = 1). Raised intraocular pressure was present before treatment in 11.1 % of cases (n = 4). Tumor biopsy was performed in 19% of cases (n = 7). Four patients had undergone an initial incomplete surgical excision of tumor before radiotherapy. Surgical preparation of the eye with tantalum ring positioning had been performed in all cases 3-4 weeks before irradiation. The prescribed dose was 60 Cobalt Gray Equivalent (CGE) of proton beam radiotherapy delivered in four fractions on four consecutive days. RESULTS The median follow-up was 50 months (mean 60.5, range 15-136). One patient (2.7%) was lost to follow-up. None of the patients showed tumor progression, local recurrence, or metastasis. None of the patients required secondary enucleation. Cataract was developed in 62% of patients, glaucoma in two cases (6%) after irradiation, and hyphema with the aggravation of pre-existing glaucoma in one patient. No patients developed neovascular glaucoma. CONCLUSIONS Proton beam therapy appears to be the treatment of choice for the conservative treatment of iris melanomas with excellent tumor control and an acceptable rate of complications. Longer follow-up studies on a larger series is necessary to consolidate these results.
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Thorp N, Taylor R. Management of Central Nervous System Tumours in Children. Clin Oncol (R Coll Radiol) 2014; 26:438-45. [DOI: 10.1016/j.clon.2014.04.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 04/07/2014] [Indexed: 10/25/2022]
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La Rosa V, Kacperek A, Royle G, Gibson A. Range verification for eye proton therapy based on proton-induced x-ray emissions from implanted metal markers. Phys Med Biol 2014; 59:2623-38. [PMID: 24786372 DOI: 10.1088/0031-9155/59/11/2623] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Metal fiducial markers are often implanted on the back of the eye before proton therapy to improve target localization and reduce patient setup errors. We aim to detect characteristic x-ray emissions from metal targets during proton therapy to verify the treatment range accuracy. Initially gold was chosen for its biocompatibility properties. Proton-induced x-ray emissions (PIXE) from a 15 mm diameter gold marker were detected at different penetration depths of a 59 MeV proton beam at the CATANA proton facility at INFN-LNS (Italy). The Monte Carlo code Geant4 was used to reproduce the experiment and to investigate the effect of different size markers, materials, and the response to both mono-energetic and fully modulated beams. The intensity of the emitted x-rays decreases with decreasing proton energy and thus decreases with depth. If we assume the range to be the depth at which the dose is reduced to 10% of its maximum value and we define the residual range as the distance between the marker and the range of the beam, then the minimum residual range which can be detected with 95% confidence level is the depth at which the PIXE peak is equal to 1.96 σ(bkg), which is the standard variation of the background noise. With our system and experimental setup this value is 3 mm, when 20 GyE are delivered to a gold marker of 15 mm diameter. Results from silver are more promising. Even when a 5 mm diameter silver marker is placed at a depth equal to the range, the PIXE peak is 2.1 σ(bkg). Although these quantitative results are dependent on the experimental setup used in this research study, they demonstrate that the real-time analysis of the PIXE emitted by fiducial metal markers can be used to derive beam range. Further analysis are needed to demonstrate the feasibility of the technique in a clinical setup.
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Affiliation(s)
- Vanessa La Rosa
- Department of Medical Physics and Bioengineering, University College London, WC1E 6BT, UK
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Slopsema RL, Mamalui M, Zhao T, Yeung D, Malyapa R, Li Z. Dosimetric properties of a proton beamline dedicated to the treatment of ocular disease. Med Phys 2013; 41:011707. [DOI: 10.1118/1.4842455] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Aitkenhead AH, Bugg D, Rowbottom CG, Smith E, Mackay RI. Modelling the throughput capacity of a single-accelerator multitreatment room proton therapy centre. Br J Radiol 2013; 85:e1263-72. [PMID: 23175492 DOI: 10.1259/bjr/27428078] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE We describe a model for evaluating the throughput capacity of a single-accelerator multitreatment room proton therapy centre with the aims of (1) providing quantitative estimates of the throughput and waiting times and (2) providing insight into the sensitivity of the system to various physical parameters. METHODS A Monte Carlo approach was used to compute various statistics about the modelled centre, including the throughput capacity, fraction times for different groups of patients and beam waiting times. A method of quantifying the saturation level is also demonstrated. RESULTS Benchmarking against the MD Anderson Cancer Center showed good agreement between the modelled (140 ± 4 fractions per day) and reported (133 ± 35 fractions per day) throughputs. A sensitivity analysis of that system studied the impact of beam switch time, the number of treatment rooms, patient set-up times and the potential benefit of having a second accelerator. Finally, scenarios relevant to a potential UK facility were studied, finding that a centre with the same four-room, single-accelerator configuration as the MD Anderson Cancer Center but handling a more complex UK-type caseload would have a throughput reduced by approximately 19%, but still be capable of treating in excess of 100 fractions per 16-h treatment day. CONCLUSIONS The model provides a useful tool to aid in understanding the operating dynamics of a proton therapy facility, and for investigating potential scenarios for prospective centres. ADVANCES IN KNOWLEDGE The model helps to identify which technical specifications should be targeted for future improvements.
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Affiliation(s)
- A H Aitkenhead
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK.
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Fassi A, Riboldi M, Forlani CF, Baroni G. Optical eye tracking system for noninvasive and automatic monitoring of eye position and movements in radiotherapy treatments of ocular tumors. APPLIED OPTICS 2012; 51:2441-2450. [PMID: 22614424 DOI: 10.1364/ao.51.002441] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/06/2012] [Indexed: 06/01/2023]
Abstract
A noninvasive eye tracking system based on infrared 3-D video-oculographic techniques is proposed for the automatic monitoring of eye position and orientation in external beam radiotherapy of ocular tumors. The presented method can be applied for the real-time estimation of lesion position and tumor-beam misalignments, allowing automatic patient setup and eye movement gated treatments. A prototypal eye tracker was developed and tested on five subjects, achieving gaze estimation errors of 0.5° and eye monitoring frequencies of 125 Hz. The proposed application can potentially improve quality and efficacy of ocular radiotherapy treatments, currently based on invasive, qualitative, and manual control procedures.
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Affiliation(s)
- Aurora Fassi
- Department of Bioengineering, Politecnico di Milano, 20133 Milano, Italy.
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Cywicka-Jakiel T, Stolarczyk L, Swakoń J, Olko P, Waligórski M. Individual patient shielding for a proton eye therapy facility. RADIAT MEAS 2010. [DOI: 10.1016/j.radmeas.2010.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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