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Hachadorian RL, Bruza P, Jermyn M, Gladstone DJ, Zhang R, Jarvis LA, Pogue BW. Remote dose imaging from cherenkov light using spatially-resolved CT calibration in breast radiotherapy. Med Phys 2022; 49:4018-4025. [PMID: 35304768 DOI: 10.1002/mp.15614] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/16/2022] [Accepted: 03/10/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Imaging Cherenkov light during radiotherapy allows the visualization and recording of frame-by-frame relative maps of the dose being delivered to the tissue at each control point used throughout treatment, providing one of the most complete real-time means of treatment quality assurance. In non-turbid media, the intensity of Cherenkov light is linear with surface dose deposited, however the emission from patient tissue is well-known to be reduced by absorbing tissue components such as hemoglobin, fat, water and melanin, and diffused by the scattering components of tissue. Earlier studies have shown that bulk correction could be achieved by using the patient planning CT scan for attenuation correction. METHODS In this study, CT maps were used for correction of spatial variations in emissivity. Testing was completed on Cherenkov images from radiotherapy treatments of post-lumpectomy breast cancer patients (n = 13), combined with spatial renderings of the patient radiodensity (CT number) from their planning CT scan. RESULTS The correction technique was shown to provide a pixel-by-pixel correction that suppressed many of the inter- and intra-patient differences in the Cherenkov light emitted per unit dose. This correction was established from a calibration curve that correlated Cherenkov light intensity to surface-rendered CT number (R6MV 2 = 0.70 and R10MV 2 = 0.72). The corrected Cherenkov intensity per unit dose standard error was reduced by nearly half (from ∼30% to ∼17%). CONCLUSIONS This approach provides evidence that the planning CT scan can mitigate some of the tissue-specific attenuation in Cherenkov images, allowing them to be translated into near surface dose images. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
| | - Michael Jermyn
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
| | - David J Gladstone
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Rongxiao Zhang
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Lesley A Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, NH
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth, Dartmouth College, Hanover, NH.,DoseOptics LLC, NH, Lebanon
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Decker SM, Alexander DA, Hachadorian RL, Zhang R, Gladstone DJ, Bruza P, Pogue BW. Estimation of diffuse Cherenkov optical emission from external beam radiation build-up in tissue. J Biomed Opt 2021; 26:JBO-210129RR. [PMID: 34545714 PMCID: PMC8451315 DOI: 10.1117/1.jbo.26.9.098003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Optical imaging of Cherenkov emission during radiation therapy could be used to verify dose delivery in real-time if a more comprehensive quantitative understanding of the factors affecting emission intensity could be developed. AIM This study aims to explore the change in diffuse Cherenkov emission intensity with x-ray beam energy from irradiated tissue, both theoretically and experimentally. APPROACH Derivation of the emitted Cherenkov signal was achieved using diffusion theory, and experimental studies with 6 to 18 MV energy x-rays were performed in tissue phantoms to confirm the model predictions as related to the radiation build-up factor with depth into tissue. RESULTS Irradiation at lower x-ray energies results in a greater surface dose and higher build-up slope, which results in a ∼46 % greater diffusely emitted Cherenkov signal per unit dose at 6 MV relative to 18 MV x-rays. However, this phenomenon competes with a decrease in signal from less Cherenkov photons being generated at lower energies, a ∼44 % reduction at 6 versus 18 MV. The result is an emitted Cherenkov signal that is nearly constant with beam energy. CONCLUSIONS This study explains why the observed Cherenkov emission from tissue is not a strong function of beam energy, despite the known strong correlation between Cherenkov intensity and particle energy in the absence of build-up and scattering effects.
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Affiliation(s)
- Savannah M. Decker
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | - Daniel A. Alexander
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
| | | | - Rongxiao Zhang
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth–Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - David J. Gladstone
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- Norris Cotton Cancer Center, Dartmouth–Hitchcock Medical Center, Lebanon, New Hampshire, United States
| | - Petr Bruza
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
| | - Brian W. Pogue
- Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire, United States
- Dartmouth College, Geisel School of Medicine, Department of Medicine, Hanover, New Hampshire, United States
- DoseOptics LLC, Lebanon, New Hampshire, United States
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Jarvis LA, Hachadorian RL, Jermyn M, Bruza P, Alexander DA, Tendler II, Williams BB, Gladstone DJ, Schaner PE, Zaki BI, Pogue BW. Initial Clinical Experience of Cherenkov Imaging in External Beam Radiation Therapy Identifies Opportunities to Improve Treatment Delivery. Int J Radiat Oncol Biol Phys 2021; 109:1627-1637. [PMID: 33227443 PMCID: PMC10544920 DOI: 10.1016/j.ijrobp.2020.11.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/05/2020] [Accepted: 11/05/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE The value of Cherenkov imaging as an on-patient, real-time, treatment delivery verification system was examined in a 64-patient cohort during routine radiation treatments in a single-center study. METHODS AND MATERIALS Cherenkov cameras were mounted in treatment rooms and used to image patients during their standard radiation therapy regimen for various sites, predominantly for whole breast and total skin electron therapy. For most patients, multiple fractions were imaged, with some involving bolus or scintillators on the skin. Measures of repeatability were calculated with a mean distance to conformity (MDC) for breast irradiation images. RESULTS In breast treatments, Cherenkov images identified fractions when treatment delivery resulted in dose on the contralateral breast, the arm, or the chin and found nonideal bolus positioning. In sarcoma treatments, safe positioning of the contralateral leg was monitored. For all 199 imaged breast treatment fields, the interfraction MDC was within 7 mm compared with the first day of treatment (with only 7.5% of treatments exceeding 3 mm), and all but 1 fell within 7 mm relative to the treatment plan. The value of imaging dose through clear bolus or quantifying surface dose with scintillator dots was examined. Cherenkov imaging also was able to assess field match lines in cerebral-spinal and breast irradiation with nodes. Treatment imaging of other anatomic sites confirmed the value of surface dose imaging more broadly. CONCLUSIONS Daily radiation therapy can be imaged routinely via Cherenkov emissions. Both the real-time images and the posttreatment, cumulative images provide surrogate maps of surface dose delivery that can be used for incident discovery and/or continuous improvement in many delivery techniques. In this initial 64-patient cohort, we discovered 6 minor incidents using Cherenkov imaging; these otherwise would have gone undetected. In addition, imaging provides automated, quantitative metrics useful for determining the quality of radiation therapy delivery.
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Affiliation(s)
- Lesley A Jarvis
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
| | | | - Michael Jermyn
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | | | - Irwin I Tendler
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Benjamin B Williams
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - David J Gladstone
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire; Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
| | - Philip E Schaner
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Bassem I Zaki
- Department of Medicine, Section of Radiation Oncology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth, Hanover, New Hampshire
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Hachadorian RL, Bruza P, Jermyn M, Gladstone DJ, Pogue BW, Jarvis LA. Imaging radiation dose in breast radiotherapy by X-ray CT calibration of Cherenkov light. Nat Commun 2020; 11:2298. [PMID: 32385233 PMCID: PMC7210272 DOI: 10.1038/s41467-020-16031-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 03/31/2020] [Indexed: 01/01/2023] Open
Abstract
Imaging Cherenkov emission during radiation therapy cancer treatments can provide a real-time, non-contact sampling of the entire dose field. The emitted Cherenkov signal generated is proportional to deposited dose, however, it is affected by attenuation from the intrinsic tissue optical properties of the patient, which in breast, ranges from primarily adipose to fibroglandular tissue. Patients being treated with whole-breast X-ray radiotherapy (n = 13) were imaged for 108 total fractions, to establish correction factors from the linear relationships between Cherenkov light and CT number (HU). This study elucidates this relationship in vivo, and a correction factor approach is used to scale each image to improve the linear correlation between Cherenkov emission intensity and dose ([Formula: see text]). This study provides a major step towards direct quantitative radiation dose imaging in humans by utilizing non-contact camera sensing of Cherenkov emission during the radiation therapy treatment.
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Affiliation(s)
- R L Hachadorian
- Thayer School of Engineering, Dartmouth College, 14 Engineering Dr., Hanover, NH, 03755, USA
| | - P Bruza
- Thayer School of Engineering, Dartmouth College, 14 Engineering Dr., Hanover, NH, 03755, USA
| | - M Jermyn
- Thayer School of Engineering, Dartmouth College, 14 Engineering Dr., Hanover, NH, 03755, USA
- DoseOptics LLC, 16 Cavendish Ct., Lebanon, NH, 03766, USA
| | - D J Gladstone
- Thayer School of Engineering, Dartmouth College, 14 Engineering Dr., Hanover, NH, 03755, USA
- Geisel School of Medicine, Dartmouth College, 1 Rope Ferry Road, Hanover, NH, 03755, USA
- Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, 1 Medical Center Dr., Lebanon, NH, 03756, USA
| | - B W Pogue
- Thayer School of Engineering, Dartmouth College, 14 Engineering Dr., Hanover, NH, 03755, USA
- DoseOptics LLC, 16 Cavendish Ct., Lebanon, NH, 03766, USA
- Geisel School of Medicine, Dartmouth College, 1 Rope Ferry Road, Hanover, NH, 03755, USA
- Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, 1 Medical Center Dr., Lebanon, NH, 03756, USA
| | - L A Jarvis
- Geisel School of Medicine, Dartmouth College, 1 Rope Ferry Road, Hanover, NH, 03755, USA.
- Norris Cotton Cancer Center at Dartmouth Hitchcock Medical Center, 1 Medical Center Dr., Lebanon, NH, 03756, USA.
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