Dose uncertainty and resolution of polymer gel dosimetry using an MRI guided radiation therapy system’s onboard 0.35 T scanner

Maraghechi, B.; Gach, H. Michael; Setianegara, Jufri; Yang, Deshan; Li, H. Harold

doi:10.1016/j.ejmp.2020.04.004

Cited by 15 publications

(10 citation statements)

References 27 publications

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“…The strong magnetic field of the MRI subunit on MR-Linacs has an influence on the performance of many dosimeters. Studies were conducted to investigate the possible influence of the magnetic field on the dose response of 3D dosimeters and to gain confidence on the useability of an MR-Linac system on polymer gel dosimeters [ 93 , 395 , 396 , 397 , 398 ], radiochromic dosimeters [ 197 , 199 ] and Fricke gel dosimeters [ 399 ]. No detectable effect of the magnetic field on the dose-response was found in any of the 3D dosimeters.…”

Section: Towards 4d Radiation Dosimetrymentioning

confidence: 99%

Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D

Deene

2022

Gels

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Gel dosimetry was developed in the 1990s in response to a growing need for methods to validate the radiation dose distribution delivered to cancer patients receiving high-precision radiotherapy. Three different classes of gel dosimeters were developed and extensively studied. The first class of gel dosimeters is the Fricke gel dosimeters, which consist of a hydrogel with dissolved ferrous ions that oxidize upon exposure to ionizing radiation. The oxidation results in a change in the nuclear magnetic resonance (NMR) relaxation, which makes it possible to read out Fricke gel dosimeters by use of quantitative magnetic resonance imaging (MRI). The radiation-induced oxidation in Fricke gel dosimeters can also be visualized by adding an indicator such as xylenol orange. The second class of gel dosimeters is the radiochromic gel dosimeters, which also exhibit a color change upon irradiation but do not use a metal ion. These radiochromic gel dosimeters do not demonstrate a significant radiation-induced change in NMR properties. The third class is the polymer gel dosimeters, which contain vinyl monomers that polymerize upon irradiation. Polymer gel dosimeters are predominantly read out by quantitative MRI or X-ray CT. The accuracy of the dosimeters depends on both the physico-chemical properties of the gel dosimeters and on the readout technique. Many different gel formulations have been proposed and discussed in the scientific literature in the last three decades, and scanning methods have been optimized to achieve an acceptable accuracy for clinical dosimetry. More recently, with the introduction of the MR-Linac, which combines an MRI-scanner and a clinical linear accelerator in one, it was shown possible to acquire dose maps during radiation, but new challenges arise.

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Section: Towards 4d Radiation Dosimetrymentioning

confidence: 99%

Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D

Deene

2022

Gels

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“…Another application of qMRI in RT could be real‐time visualization of biological dose. Because radiation dosimetry can be assessed in vitro using Bang gels, one can envisage extension to in vivo applications 135 . Through a deeper understanding of the short‐term effects of dose on tissue, we may find an MRI contrast mechanism, such as CEST or DWI, is sensitive to the short‐term biological effect of the treatment beam.…”

Section: Quantitative Mrimentioning

confidence: 99%

The future of MRI in radiation therapy: Challenges and opportunities for the MR community

Goodburn

Philippens

Lefebvre

et al. 2022

Magnetic Resonance in Med

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Radiation therapy is a major component of cancer treatment pathways worldwide. The main aim of this treatment is to achieve tumor control through the delivery of ionizing radiation while preserving healthy tissues for minimal radiation toxicity. Because radiation therapy relies on accurate localization of the target and surrounding tissues, imaging plays a crucial role throughout the treatment chain. In the treatment planning phase, radiological images are essential for defining target volumes and organs-at-risk, as well as providing elemental composition (e.g., electron density) information for radiation dose calculations. At treatment, onboard imaging informs patient setup and could be used to guide radiation dose placement for sites affected by motion. Imaging is also an important tool for treatment response assessment and treatment plan adaptation. MRI, with its excellent soft tissue contrast and capacity to probe functional tissue properties, holds great untapped potential for transforming treatment paradigms in radiation therapy. The MR in Radiation Therapy ISMRM Study Group was established to provide a forum within the MR community to discuss the unmet needs and fuel opportunities for further advancement of MRI for radiation therapy applications. During the summer of 2021, the study group organized its first virtual workshop, attended by a diverse international group of clinicians, scientists, and clinical physicists, to explore our predictions for the future of MRI in radiation therapy for the next 25 years. This article reviews the main findings from the event and considers the opportunities and challenges of reaching our vision for the future in this expanding field.

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“…The readout techniques used in gel dosimetry have a great influence on their final application; in most cases, the available analytical methods in clinical facilities are favored. Thus, efforts have been made during the last few decades to apply MRI [ 60 , 61 ] and even use onboard MRI scanners included in modern MRI-based IGRT [ 62 ], X-ray computed tomography (CT) [ 58 , 63 , 64 ], or optical computed tomography methods (OCT) [ 65 , 66 , 67 ] to deliver 3D response distributions in gel dosimetry systems in clinical applications. Raman spectroscopy represents another technique widely used in gel dosimetry, but mainly for research purposes, as it provides quantitative information on the consumption of each reactive species without modifying the dosimeters and is capable of obtaining 2D distributions and even 3D distribution at the microscale [ 68 , 69 , 70 ].…”

Section: Readout Techniquesmentioning

confidence: 99%

Chemical Overview of Gel Dosimetry Systems: A Comprehensive Review

Macchione

Páez

Strumia

et al. 2022

Gels

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Advances in radiotherapy technology during the last 25 years have significantly improved both dose conformation to tumors and the preservation of healthy tissues, achieving almost real-time feedback by means of high-precision treatments and theranostics. Owing to this, developing high-performance systems capable of coping with the challenging requirements of modern ionizing radiation is a key issue to overcome the limitations of traditional dosimeters. In this regard, a deep understanding of the physicochemical basis of gel dosimetry, as one of the most promising tools for the evaluation of 3D high-spatial-resolution dose distributions, represents the starting point for developing new and innovative systems. This review aims to contribute thorough descriptions of the chemical processes and interactions that condition gel dosimetry outputs, often phenomenologically addressed, and particularly formulations reported since 2017.

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Dose uncertainty and resolution of polymer gel dosimetry using an MRI guided radiation therapy system’s onboard 0.35 T scanner

Cited by 15 publications

References 27 publications

Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D

Radiation Dosimetry by Use of Radiosensitive Hydrogels and Polymers: Mechanisms, State-of-the-Art and Perspective from 3D to 4D

The future of MRI in radiation therapy: Challenges and opportunities for the MR community

Chemical Overview of Gel Dosimetry Systems: A Comprehensive Review

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