Step-and-Shoot IMRT by Siemens Beams

Russo, Mariateresa; Piermattei, Angelo; Greco, Francesca; Azario, L.; Orlandini, L.C.; Zucca, S.; Cilla, Savino; Menna, S.; Grusio, Mattia; Chiatti, Leonardo; Fidanzio, A.

doi:10.1177/1533034615590962

Cited by 5 publications

(9 citation statements)

References 31 publications

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“…The first test is representative of the accuracy of the dose reconstructed at a reference point while the second test is the γ -analysis that supplies a transit dosimetry to verify the treatment reproducibility. Both tests supply useful information about the presence of dosimetric errors due to the patient setup, linac output variations, beam interruptions, dose calculations [ 16 , 22 ], and the presence of patient morphological changes [ 3 , 27 ]. The in vivo EPID-based dosimetry workflow applied in this study is shown in Fig 1 .…”

Section: Ivd Proceduresmentioning

confidence: 99%

“…In this environment, IVD checks are strongly recommended to avoid important dosimetric discrepancies. Several researchers [ 15 , 16 , 17 ] have demonstrated the advantages of reconstructing the delivered dose using an amorphous-silicon electronic portal imaging device (EPID), which presents favourable characteristics such as fast image acquisition and high resolution. In addition, IVD methods are still not widely used due to fear of the increased workload required to implement them [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

“…Some groups [ 18 , 19 , 20 , 21 ] have recently performed patient dose verification using on-treatment EPID transmission images. In the present study, however, the causes of a dosimetric disagreement between the planned and delivered treatment have been analysed and corrected during the course of radiotherapy using an IVD method based on EPID [ 3 , 16 , 22 , 23 , 24 ]. The efficiency of the corrections performed has been evaluated and the added workload needed for the entire procedure has been registered.…”

Section: Introductionmentioning

confidence: 99%

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Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device

Piermattei

Wang

et al. 2018

PLoS ONE

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High conformal techniques such as intensity-modulated radiation therapy and volumetric-modulated arc therapy are widely used in overloaded radiotherapy departments. In vivo dosimetric screening is essential in this environment to avoid important dosimetric errors. This work examines the feasibility of introducing in vivo dosimetry (IVD) checks in a radiotherapy routine. The causes of dosimetric disagreements between delivered and planned treatments were identified and corrected during the course of treatment. The efficiency of the corrections performed and the added workload needed for the entire procedure were evaluated.The IVD procedure was based on an electronic portal imaging device. A total of 3682 IVD tests were performed for 147 patients who underwent head and neck, abdomen, pelvis, breast, and thorax radiotherapy treatments. Two types of indices were evaluated and used to determine if the IVD tests were within tolerance levels: the ratio R between the reconstructed and planned isocentre doses and a transit dosimetry based on the γ-analysis of the electronic portal images. The causes of test outside tolerance level were investigated and corrected and IVD test was repeated during subsequent fraction. The time needed for each step of the IVD procedure was registered. Pelvis, abdomen, and head and neck treatments had 10% of tests out of tolerance whereas breast and thorax treatments accounted for up to 25%. The patient setup was the main cause of 90% of the IVD tests out of tolerance and the remaining 10% was due to patient morphological changes. An average time of 42 min per day was sufficient to monitor a daily workload of 60 patients in treatment. This work shows that IVD performed with an electronic portal imaging device is feasible in an overloaded department and enables the timely realignment of the treatment quality indices in order to achieve a patient’s final treatment compliant with the one prescribed.

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Section: Ivd Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device

Piermattei

Wang

et al. 2018

PLoS ONE

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“… 2 – 6 The in vivo dosimetry (IVD) is strongly recommended by various organizations 7 - 10 so that in some countries, IVD tests are required as a routine check to detect the causes of dosimetric errors. 11 , 12 Several researchers 13 - 35 have implemented IVD systems to reconstruct the delivered dose to the patients using the amorphous silicon electronic portal imaging device (aSi-EPID) associated with the linear accelerator (LINAC). The results showed that aSi-EPIDs can be used to reconstruct the dose in single points, 2 dimensional (2D), and entire 3-dimensional (3-D) dose distribution.…”

Section: Introductionmentioning

confidence: 99%

A Feasibility Study for in vivo Dosimetry Procedure in Routine Clinical Practice

Falco¹,

Giancaterino²,

Nicola³

et al. 2018

Technol Cancer Res Treat

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Purpose:The aim of the in vivo dosimetry, during the fractionated radiation therapy, is the verification of the correct dose delivery to patient. Nowadays, in vivo dosimetry procedures for photon beams are based on the use of the electronic portal imaging device and dedicated software to elaborate electronic portal imaging device images.Methods:In total, 8474 in vivo dosimetry tests were carried out for 386 patients treated with 3-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and volumetric modulated arc therapy techniques, using the SOFTDISO. SOFTDISO is a dedicated software that uses electronic portal imaging device images in order to (1) calculate the R index, that is, the ratio between daily reconstructed dose and the planned one at isocenter and (2) perform a γ-like analysis between the signals, S, of a reference electronic portal imaging device image and that obtained in a daily fraction. It supplies 2 indexes, the percentage γ% of points with γ < 1 and the mean γ value, γmean. In γ-like analysis, the pass criteria for the signals agreement ΔS% and distance to agreement Δd have been selected based on the clinical experience and technology used. The adopted tolerance levels for the 3 indexes were fixed in 0.95 ≤ R ≤ 1.05, γ% ≥ 90%, and γmean ≤ 0.5.Results:The results of R ratio, γ-like, and a visual inspection of these data reported on a monitor screen permitted to individuate 2 classes of errors (1) class 1 that included errors due to inadequate standard quality controls and (2) class 2, due to patient morphological changes. Depending on the technique and anatomical site, a maximum of 18% of tests had at least 1 index out of tolerance; once removed the causes of class-1 errors, almost all patients (except patients with 4 lung and 2 breast cancer treated with 3-dimensional conformal radiotherapy) presented mean indexes values (trueR¯, trueγ¯%, and γ¯mean ) within tolerance at the end of treatment course. Class-2 errors were found in some patients.Conclusions:The in vivo dosimetry procedure with SOFTDISO resulted easily implementable, able to individuate errors with a limited workload.

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“…Thirdly, Piermattei et al have focused on calculating the dose at the isocenter point by means of correlation ratios. 16 – 18 The latter method has the advantage of being of simple implementation but also has the drawback of providing only point dose. In addition to the in-house methods above, there are currently 2 commercial EPID IVD solutions: Dosimetry Check 19 (by Math Resolutions, Columbia, MD) and EPIgray 20 (by DOSIsoft, Cachan, France).…”

Section: Introductionmentioning

confidence: 99%

A Simple Method for 2-D In Vivo Dosimetry by Portal Imaging

Peca

Brown

Smith

2017

Technol Cancer Res Treat

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Purpose:To improve patient safety and treatment quality, verification of dose delivery in radiotherapy is desirable. We present a simple, easy-to-implement, open-source method for in vivo planar dosimetry of conformal radiotherapy by electronic portal imaging device (EPID).Methods:Correlation ratios, which relate dose in the mid-depth of slab phantoms to transit EPID signal, were determined for multiple phantom thicknesses and field sizes. Off-axis dose is corrected for by means of model-based convolution. We tested efficacy of dose reconstruction through measurements with off-reference values of attenuator thickness, field size, and monitor units. We quantified the dose calculation error in the presence of thickness changes to simulate anatomical or setup variations. An example of dose calculation on patient data is provided.Results:With varying phantom thickness, field size, and monitor units, dose reconstruction was almost always within 3% of planned dose. In the presence of thickness changes from planning CT, the dose discrepancy is exaggerated by up to approximately 1.5% for 1 cm changes upstream of the isocenter plane and 4% for 1 cm changes downstream.Conclusion:Our novel electronic portal imaging device in vivo dosimetry allows clinically accurate 2-dimensional reconstruction of dose inside a phantom/patient at isocenter depth. Due to its simplicity, commissioning can be performed in a few hours per energy and may be modified to the user’s needs. It may provide useful dose delivery information to detect harmful errors, guide adaptive radiotherapy, and assure quality of treatment.

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Step-and-Shoot IMRT by Siemens Beams

Cited by 5 publications

References 31 publications

Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device

Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device

A Feasibility Study for in vivo Dosimetry Procedure in Routine Clinical Practice

A Simple Method for 2-D In Vivo Dosimetry by Portal Imaging

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