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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, 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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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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