Initial clinical experience with Epid-based in-vivo dosimetry for VMAT treatments of head-and-neck tumors

Cilla, Savino; Meluccio, Daniela; Fidanzio, A.; Azario, L.; Ianiro, A.; Macchia, G.; Digesù, Cinzia; Deodato, Francesco; Valentini, Vincenzo; Morganti, Alessio Giuseppe; Piermattei, Angelo

doi:10.1016/j.ejmp.2015.09.007

Cited by 35 publications

(31 citation statements)

References 28 publications

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“…Unlike in PC, the passing rates in HNC generally decreased as treatment progressed. Cilla et al conducted a study on ongoing patient QA using integrated EPID images in HNC VMAT cases . In their investigation of the gamma passing rates of integrated EPID images, they determined a gamma passing rate (3%/3 mm) of 92.9%, which suggested that the discrepancies between the photon fluences of the first fraction and subsequent fractions were caused by patient positioning errors and anatomical variation.…”

Section: Discussionmentioning

confidence: 99%

“…In those studies, the point dose was estimated based on the photon fluence using a back‐projection algorithm. In other studies, point dose and dose distributions were evaluated using integrated EPID images for various treatment sites, and gamma analyses were performed throughout VMAT. Kang et al assessed the relationship between interfractional setup error and integrated EPID images for postmastectomy radiation therapy.…”

Section: Introductionmentioning

confidence: 99%

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Analyses of integrated EPID images for on‐treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy

Matsushita

Nakamura

Sasaki

et al. 2020

J Applied Clin Med Phys

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Purpose: To investigate the effects of interfractional variation, such as anatomical changes and setup errors, on dose delivery during treatment for prostate cancer (PC) and head and neck cancer (HNC) by courses of volumetric modulated arc therapy (VMAT) aided by on-treatment electronic portal imaging device (EPID) images.Methods: Seven patients with PC and 20 patients with HNC who had received VMAT participated in this study. After obtaining photon fluence at the position of the EPID for each treatment arc from on-treatment integrated EPID images, we calculated the differences between the fluence for the first fraction and each subsequent fraction for each arc. The passing rates were investigated based on a tolerance level of 3% of the maximum fluence during the treatment courses and the correlations between the passing rates and anatomical changes.Results: In PC, the median and lowest passing rates were 99.8% and 95.2%, respectively. No correlations between passing rates and interfractional variation were found. In HNC, the median passing rate of all fractions was 93.0%, and the lowest passing rate was 79.6% during the 35th fraction. Spearman's correlation coefficients between the passing rates and changes in weight or neck volume were − 0.77 and − 0.74, respectively.Conclusions: Analyses of the on-treatment EPID images facilitates estimates of the interfractional anatomical variation in HNC patients during VMAT and thus improves assessments of the need for re-planning or adaptive strategies and the timing thereof.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analyses of integrated EPID images for on‐treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy

Matsushita

Nakamura

Sasaki

et al. 2020

J Applied Clin Med Phys

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“…Treatment reproducibility, instead, is performed by γ ‐analysis comparison between daily portal images. We demonstrated that this procedure, even if it is not a true 2D dosimetric comparison, can trace back the causes of transit signal changes, allowing a prompt action to remove any clinically relevant dose discrepancies before compromising the aim of patient curative treatment . The small number of patients enrolled in the present study does not allow a statistically significant comparison between the results obtained for the patients treated with and without ABC system.…”

Section: Discussionmentioning

confidence: 77%

“…The γ ‐analysis tests were evaluated in terms of percentage of points with γ value less than one ( γ % ) and in terms of mean γ values ( γ mean ). Based on previous experience on other anatomical sites, a 3% (global)‐3 mm criteria was adopted. Alert criteria of γ % < 90% and γ mean > 0.67 were chosen, to accept only 10% of values above 3%/3 mm and an average discrepancy of 2%/2 mm.…”

Section: Methodsmentioning

confidence: 99%

“…Recent publications have investigated the new challenges of epid‐based IVD for more complex treatments as IMRT or VMAT, showing the feasibility and the sensitivity of this approach to detect dose discrepancies also for these complex techniques . By routine clinical use of EPID‐based IVD, major dosimetric discrepancies due to anatomical variations and serious errors including plan transfer errors due to record‐and‐verify network failure were detected . A large clinical experience has been recently carried out at the Radiotherapy Centre of the Fondazione Policlinico Universitario A. Gemelli in Rome by means of an automated Epid‐based IVD procedure for more than 800 patients.…”

Section: Introductionmentioning

confidence: 99%

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Epid‐based in vivo dose verification for lung stereotactic treatments delivered with multiple breath‐hold segmented volumetric modulated arc therapy

Cilla

Ianiro

Craus

et al. 2019

J Applied Clin Med Phys

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We evaluated an EPID‐based in‐vivo dosimetry (IVD) method for the dose verification and the treatment reproducibility of lung SBRT‐VMAT treatments in clinical routine. Ten patients with lung metastases treated with Elekta VMAT technique were enrolled. All patients were irradiated in five consecutive fractions, with total doses of 50 Gy. Set‐up was carried out with the Elekta stereotactic body frame. Eight patients were simulated and treated using the Active Breath Control (ABC) system, a spirometer enabling patients to maintain a breath‐hold at a predetermined lung volume. Two patients were simulated and treated in free‐breathing using an abdominal compressor. IVD was performed using the SOFTDISO software. IVD tests were evaluated by means of (a) ratio R between daily in‐vivo isocenter dose and planned dose and (b) γ‐analysis between EPID integral portal images in terms of percentage of points with γ‐value smaller than one (γ%) and mean γ‐values (γmean) using a 3%(global)/3 mm criteria. Alert criteria of ±5% for R ratio, γ% < 90%, and γmean > 0.67 were chosen. 50 transit EPID images were acquired. For the patients treated with ABC spirometer, the results reported a high level of accuracy in dose delivery with 100% of tests within ±5%. The γ‐analysis showed a mean value of γmean equal to 0.21 (range: 0.04–0.56) and a mean γ% equal to 96.9 (range: 78–100). Relevant discrepancies were observed only for the two patients treated without ABC, mainly due to a blurring dose effect due to residual respiratory motion. Our method provided a fast and accurate procedure in clinical routine for verifying delivered dose as well as for detecting errors.

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A high DQE water‐equivalent EPID employing an array of plastic‐scintillating fibers for simultaneous imaging and dosimetry in radiotherapy

et al. 2018

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Initial clinical experience with Epid-based in-vivo dosimetry for VMAT treatments of head-and-neck tumors

Cited by 35 publications

References 28 publications

Analyses of integrated EPID images for on‐treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy

Analyses of integrated EPID images for on‐treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy

Epid‐based in vivo dose verification for lung stereotactic treatments delivered with multiple breath‐hold segmented volumetric modulated arc therapy

A high DQE water‐equivalent EPID employing an array of plastic‐scintillating fibers for simultaneous imaging and dosimetry in radiotherapy

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