<i>In vivo</i> dosimetry in UK external beam radiotherapy: current and future usage

MacDougall, N D; Graveling, Michael; Hansen, Vibeke; Brownsword, K.; Morgan, Andrew M.

doi:10.1259/bjr.20160915

Cited by 35 publications

(33 citation statements)

References 23 publications

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“…Therefore, one would expect that IVD is already an essential link in the clinical workflow of modern radiotherapy. However, very few radiotherapy centers perform IVD during beam delivery [2]. The current standard is to perform dosimetry checks using pretreatment dose measurements in phantoms, which requires major resources but cannot catch errors related to patient geometry or in beam delivery during the actual treatment [3].…”

Section: Introductionmentioning

confidence: 99%

In vivo dosimetry in external beam photon radiotherapy: Requirements and future directions for research, development, and clinical practice

Olaciregui-Ruiz

Beddar

Greer

et al. 2020

Physics and Imaging in Radiation Oncology

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External beam radiotherapy with photon beams is a highly accurate treatment modality, but requires extensive quality assurance programs to confirm that radiation therapy will be or was administered appropriately. In vivo dosimetry (IVD) is an essential element of modern radiation therapy because it provides the ability to catch treatment delivery errors, assist in treatment adaptation, and record the actual dose delivered to the patient. However, for various reasons, its clinical implementation has been slow and limited. The purpose of this report is to stimulate the wider use of IVD for external beam radiotherapy, and in particular of systems using electronic portal imaging devices (EPIDs). After documenting the current IVD methods, this report provides detailed software, hardware and system requirements for in vivo EPID dosimetry systems in order to help in bridging the current vendor-user gap. The report also outlines directions for further development and research. In vivo EPID dosimetry vendors, in collaboration with users across multiple institutions, are requested to improve the understanding and reduce the uncertainties of the system and to help in the determination of optimal action limits for error detection. Finally, the report recommends that automation of all aspects of IVD is needed to help facilitate clinical adoption, including automation of image acquisition, analysis, result interpretation, and reporting/documentation. With the guidance of this report, it is hoped that widespread clinical use of IVD will be significantly accelerated.

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Section: Introductionmentioning

confidence: 99%

In vivo dosimetry in external beam photon radiotherapy: Requirements and future directions for research, development, and clinical practice

Olaciregui-Ruiz

Beddar

Greer

et al. 2020

Physics and Imaging in Radiation Oncology

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“…Thermoluminescent dosimeters also have limited applicability due to extensive training requirements and labor‐intensive operation (Olko, ). Silicon diode detectors require cumbersome calibration making them difficult to use for routine operation (MacDougall, Graveling, Hansen, Brownsword, & Morgan, ). Furthermore, the sensitivity of silicon diode dosimeters vary with accumulated dose making them unreliable for clinical operation (Eveling, Morgan, & Pitchford, ).…”

Section: Introductionmentioning

confidence: 99%

Protein‐facilitated gold nanoparticle formation as indicators of ionizing radiation

Thaker

Pushpavanam

Bista

et al. 2019

Biotech & Bioengineering

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The use of X-ray radiation in radiotherapy is a common treatment for many cancers.Despite several scientific advances, determination of radiation delivered to the patient remains a challenge due to the inherent limitations of existing dosimeters including fabrication and operation. Here, we describe a colorimetric nanosensor that exhibits unique changes in color as a function of therapeutically relevant radiation dose (3-15 Gy). The nanosensor is formulated using a gold salt and maltose-binding protein as a templating agent, which upon exposure to ionizing radiation is converted to gold nanoparticles. The formation of gold nanoparticles from colorless precursor salts renders a change in color that can be observed visually. The dose-dependent multicolored response was quantified through a simple ultraviolet-visible spectrophotometer and the peak shift associated with the different colored dispersions was used as a quantitative indicator of therapeutically relevant radiation doses. The ease of fabrication, visual color changes upon exposure to ionizing radiation, and quantitative read-out demonstrates the potential of protein-facilitated biomineralization approaches to promote the development of next-generation detectors for ionizing radiation.

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“…Beyond point-based dosimetry, utilizing technology such as electronic portal imaging device (EPID) to measure in vivo exit dosimetry can help to mitigate uncertainties associated with detector positioning [21,22]. In a recent review of IVD in the UK, MacDougall et al suggest that point-based IVD, most effective for conformal radiation treatments with uniform dose, may be phased out in favor of portal imaging for highly-modulated IMRT and VMAT [23]. Essentially all linacs come equipped with EPIDs, with EPID-based dosimetry having the advantage of providing 3D information for IMRT and VMAT treatments [20].…”

Section: Discussionmentioning

confidence: 99%

Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy

Tariq

Gomez

Riegel

2019

Physics and Imaging in Radiation Oncology

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Introduction: Studies have suggested that optically stimulated luminescent dosimeters (OSLDs) can be used for in vivo dosimetry of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT). Clinical uncertainties such as placement error have not been thoroughly investigated. The purpose of this work was to measure OSLD placement error in a clinical sample and analyze its dosimetric impact. Methods and materials: The analysis consisted of three parts: first, quantification of placement error in a clinical sample of 128 patients yielding 293 cone-beam CT (CBCT) with visible OSLDs registered to the treatment plan; Second, correlation of placement error and clinical OSLD measurements; third, simulation of dosimeter placement in the treatment plan and correlation of recalculated dose with placement error. Results: In the first analysis, average placement error was 9.7 ± 9.5 mm. In the second analysis, placement error and measured-to-planned dose agreement yielded no correlation (R 2 = 0.02) for a subsample of 77 CBCTs of 55 head-and-neck patients. Average placement error was 7.0 ± 6.0 mm. Several factors, including image-guided shifts, introduced uncharacterized uncertainty to the measured-to-planned dose agreement. The third analysis isolated placement error from these other effects. Average dosimetric error was −2.4 ± 19.3%. Simulated dosimetric impact was weakly correlated with placement error (R 2 = 0.39). Removing outliers reduced the average dosimetric error to −2.1 ± 10.9%, marginally improving the correlation (R 2 = 0.44). Conclusion: Placement error can substantially impact measured-to-planned dose agreement of OSLDs in high gradient regions, demonstrating the criticality of accurate dosimeter placement for IMRT and VMAT treatments.

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In vivo dosimetry in UK external beam radiotherapy: current and future usage

Abstract: . In vivo dosimetry in UK external beam radiotherapy: current and future usage. Br J Radiol 2017; 90: 20160915.

Cited by 35 publications

References 23 publications

In vivo dosimetry in external beam photon radiotherapy: Requirements and future directions for research, development, and clinical practice

In vivo dosimetry in external beam photon radiotherapy: Requirements and future directions for research, development, and clinical practice

Protein‐facilitated gold nanoparticle formation as indicators of ionizing radiation

Dosimetric impact of placement errors in optically stimulated luminescent in vivo dosimetry in radiotherapy

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