Assessing the impact of adaptations to the clinical workflow in radiotherapy using transit in vivo dosimetry

Bossuyt, E.; Nevens, Daan; Weytjens, R.; Mokaddem, Ahmed Taieb; Verellen, Dirk

doi:10.1016/j.phro.2023.100420

Cited by 2 publications

(3 citation statements)

References 30 publications

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“…Whilst the majority of out of tolerance results in this paper were false positives, there was still a large proportion (27.1%, 45 fractions) that were considered a true positive. The overall failure rate of 5.1% is at the lower end of failure rates reported in literature and would be expected to reduce over time as the treatment process is continually improved, as found by Bossuyt et al (2023). The investigation time required for out of tolerance results is far smaller than the estimated time saved by the introduction of an automated system (compared to manual processing of results).…”

Section: Discussionmentioning

confidence: 83%

Automation to facilitate optimisation of breast radiotherapy treatments using EPID-based in vivo dosimetry

Kirby,

Chester

2024

Phys. Med. Biol.

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Objective:To use automation to facilitate the monitoring of each treatment fraction using an EPID based in-vivo dosimetry (IVD) system, allowing optimisation of breast radiotherapy delivery for individual patients and cohorts.Approach:A suite of in-house software was developed to reduce the number of manual interactions with the commercial IVD system, Dosimetry Check. An EPID specific pixel sensitivity map facilitated use of the EPID panel away from the central axis. Point dose difference and the change in standard deviation in dose were identified as useful dose metrics, with standard deviation used in preference to gamma in the presence of a systematic dose offset. Automated IVD was completed for 3261 fractions across 704 patients receiving breast radiotherapy. Main results:Multiple opportunities for treatment optimisation were identified for individual patients and across patient cohorts as a result of successful implementation of automated IVD. 5.1% of analysed fractions were out of tolerance with 27.1% of these considered true positives. True positive results were obtained on any fraction of treatment and if IVD had only been completed on the first fraction, 84.4% of true positive results would have been missed. This was made possible due to the automation that saved over 800 hours of manual intervention and stored data in an accessible database.Significance:An improved EPID calibration to allow off-axis measurement maximises the number of patients eligible for IVD (36.8% of patients in this study). We also demonstrate the importance in selecting context-specific assessment metrics and how these can lead to a managable false positive rate. We have shown that the use of fully automated IVD facilitates use on every fraction of treatment. This leads to identification of areas for treatment improvement for both individuals and across a patient cohort, expanding the uses of IVD from simply gross error detection towards treatment optimisation.

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Section: Discussionmentioning

confidence: 83%

Automation to facilitate optimisation of breast radiotherapy treatments using EPID-based in vivo dosimetry

Kirby,

Chester

2024

Phys. Med. Biol.

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“…Nevertheless, this method is time‐consuming 2 and uncertainties related to the detector positioning and dose‐rate response reduce their utility in modulated plans 3 . To go beyond the bounds of point dosimeter limitations, the use of transit dosimetry is spreading 2,4–9 . Transit dosimetry is based on the transit images formed by the radiation reaching the electronic portal imaging device (EPID), through the patient, during field irradiation.…”

Section: Introductionmentioning

confidence: 99%

“… 3 To go beyond the bounds of point dosimeter limitations, the use of transit dosimetry is spreading. 2 , 4 , 5 , 6 , 7 , 8 , 9 Transit dosimetry is based on the transit images formed by the radiation reaching the electronic portal imaging device (EPID), through the patient, during field irradiation.…”

Section: Introductionmentioning

confidence: 99%

Validation of an in vivo transit dosimetry algorithm using Monte Carlo simulations and ionization chamber measurements

Sánchez‐Artuñedo,

Pié‐Padró,

Hermida‐López

et al. 2023

J Applied Clin Med Phys

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PurposeTransit dosimetry is a safety tool based on the transit images acquired during treatment. Forward‐projection transit dosimetry software, as PerFRACTION, compares the transit images acquired with an expected image calculated from the DICOM plan, the CT, and the structure set. This work aims to validate PerFRACTION expected transit dose using PRIMO Monte Carlo simulations and ionization chamber measurements, and propose a methodology based on MPPG5a report.MethodsThe validation process was divided into three groups of tests according to MPPG5a: basic dose validation, IMRT dose validation, and heterogeneity correction validation. For the basic dose validation, the fields used were the nine fields needed to calibrate PerFRACTION and three jaws‐defined. For the IMRT dose validation, seven sweeping gaps fields, the MLC transmission and 29 IMRT fields from 10 breast treatment plans were measured. For the heterogeneity validation, the transit dose of these fields was studied using three phantoms: 10 , 30 , and a 3 cm cork slab placed between 10 cm of solid water. The PerFRACTION expected doses were compared with PRIMO Monte Carlo simulation results and ionization chamber measurements.ResultsUsing the 10 cm solid water phantom, for the basic validation fields, the root mean square (RMS) of the difference between PerFRACTION and PRIMO simulations was 0.6%. In the IMRT fields, the RMS of the difference was 1.2%. When comparing respect ionization chamber measurements, the RMS of the difference was 1.0% both for the basic and the IMRT validation. The average passing rate with a γ(2%/2 mm, TH = 20%) criterion between PRIMO dose distribution and PerFRACTION expected dose was 96.0% ± 5.8%.ConclusionWe validated PerFRACTION calculated transit dose with PRIMO Monte Carlo and ionization chamber measurements adapting the methodology of the MMPG5a report. The methodology presented can be applied to validate other forward‐projection transit dosimetry software.

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Assessing the impact of adaptations to the clinical workflow in radiotherapy using transit in vivo dosimetry

Cited by 2 publications

References 30 publications

Automation to facilitate optimisation of breast radiotherapy treatments using EPID-based in vivo dosimetry

Automation to facilitate optimisation of breast radiotherapy treatments using EPID-based in vivo dosimetry

Validation of an in vivo transit dosimetry algorithm using Monte Carlo simulations and ionization chamber measurements

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