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Saini J, Maes D, Regmi R, Fung A, Bloch C, Schwarz M, Stacey A, Chen J, Rengan R, Halasz L. Improved lateral penumbra for proton ocular treatments on a general-purpose spot scanning beamline. Phys Med 2023; 107:102551. [PMID: 36867911 DOI: 10.1016/j.ejmp.2023.102551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 01/31/2023] [Accepted: 02/18/2023] [Indexed: 03/05/2023] Open
Abstract
PURPOSE An ocular applicator that fits a commercial proton snout with an upstream range shifter to allow for treatments with sharp lateral penumbra is described. MATERIALS AND METHODS The validation of the ocular applicator consisted of a comparison of range, depth doses (Bragg peaks and spread out Bragg peaks), point doses, and 2-D lateral profiles. Measurements were made for three field sizes, 1.5, 2, and 3 cm, resulting in 15 beams. Distal and lateral penumbras were simulated in the treatment planning system for seven range-modulation combinations for beams typical of ocular treatments and a field size of 1.5 cm, and penumbra values were compared to published literature. RESULTS All the range errors were within 0.5 mm. The maximum averaged local dose differences for Bragg peaks and SOBPs were 2.6% and 1.1%, respectively. All the 30 measured point doses were within +/-3% of the calculated. The measured lateral profiles, analyzed through gamma index analysis and compared to the simulated, had pass rates greater than 96% for all the planes. The lateral penumbra increased linearly with depth, from 1.4 mm at 1 cm depth to 2.5 mm at 4 cm depth. The distal penumbra ranged from 3.6 to 4.4 mm and increased linearly with the range. The treatment time for a single 10 Gy (RBE) fractional dose ranged from 30 to 120 s, depending on the shape and size of the target. CONCLUSIONS The ocular applicator's modified design allows lateral penumbra similar to dedicated ocular beamlines while enabling planners to use modern treatment tools such as Monte Carlo and full CT-based planning with increased flexibility in beam placement.
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Affiliation(s)
- Jatinder Saini
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA.
| | - Dominic Maes
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Rajesh Regmi
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Angela Fung
- Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Charles Bloch
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Marco Schwarz
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Andrew Stacey
- Department of Ophthalmology, University of Washington School of Medicine, 750 Republican St, Seattle, WA 98109, USA
| | - Jonathan Chen
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Ramesh Rengan
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
| | - Lia Halasz
- Department of Radiation Oncology, University of Washington School of Medicine, 1959 NE Pacific St., Seattle, WA 98195, USA; Fred Hutchinson Cancer Center, 1570 N 115th St., Seattle, WA 98133, USA
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Elisei G, Pella A, Ricotti R, Via R, Fiore MR, Calvi G, Mastella E, Paganelli C, Tagaste B, Bello F, Fontana G, Meschini G, Buizza G, Valvo F, Orlandi E, Ciocca M, Baroni G. Development and validation of a new set-up simulator dedicated to ocular proton therapy at CNAO. Phys Med 2021; 82:228-239. [PMID: 33657472 DOI: 10.1016/j.ejmp.2021.01.070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 11/27/2020] [Accepted: 01/14/2021] [Indexed: 10/22/2022] Open
Abstract
An Eye Tracking System (ETS) is used at CNAO for providing a stable and reproducible ocular proton therapy (OPT) set-up, featuring a fixation light (FL) and monitoring stereo-cameras embedded in a rigid case. The aim of this work is to propose an ETS set-up simulation algorithm, that automatically provides the FL positioning in space, according to patient-specific gaze direction and avoiding interferences with patient, beam and collimator. Two configurations are provided: one in the CT room for acquiring images required for treatment planning with the patient lying on a couch, and one related to the treatment room with the patient sitting in front of the beam. Algorithm validation was performed reproducing ETS simulation (CT) and treatment (room) set-up for 30 patients previously treated at CNAO. The positioning accuracy of the device was quantified through a set of 14 control points applied to the ETS case and localizable both in the CT volume and in room X-ray images. Differences between the position of ETS reference points estimated by the algorithm and those measured by imaging systems are reported. The corresponding gaze direction deviation is on average 0.2° polar and 0.3° azimuth for positioning in CT room and 0.1° polar and 0.4° azimuth in the treatment room. The simulation algorithm was embedded in a clinically usable software application, which we assessed as capable of ensuring ETS positioning with an average accuracy of 2 mm in CT room and 1.5 mm in treatment room, corresponding to gaze direction deviations consistently lower than 1°.
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Affiliation(s)
- G Elisei
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy
| | - A Pella
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy.
| | - R Ricotti
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy
| | - R Via
- Center of Proton Therapy, Paul Scherrer Institut, 5232 Villigen, PSI, Switzerland
| | - M R Fiore
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department, Pavia, Italy
| | - G Calvi
- Centro Nazionale di Adroterapia Oncologica CNAO, Particle Accelerator Department, Pavia, Italy
| | - E Mastella
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department - Medical Physics Unit, Pavia, Italy
| | - C Paganelli
- Politecnico di Milano, Department of Electronics Information and Bioengineering, Milano, Italy
| | - B Tagaste
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy
| | - F Bello
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy
| | - G Fontana
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy
| | - G Meschini
- Politecnico di Milano, Department of Electronics Information and Bioengineering, Milano, Italy
| | - G Buizza
- Politecnico di Milano, Department of Electronics Information and Bioengineering, Milano, Italy
| | - F Valvo
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department, Pavia, Italy
| | - E Orlandi
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department, Pavia, Italy
| | - M Ciocca
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department - Medical Physics Unit, Pavia, Italy
| | - G Baroni
- Centro Nazionale di Adroterapia Oncologica CNAO, Clinical Department-Bioengineering Unit, Pavia, Italy; Politecnico di Milano, Department of Electronics Information and Bioengineering, Milano, Italy
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