Total skin electron therapy (TSET): A reimplementation using radiochromic films and IAEA TRS‐398 code of practice

Schiapparelli, P.; Zefiro, Daniele; Massone, F.; Taccini, G.

doi:10.1118/1.3442301

Cited by 18 publications

(16 citation statements)

References 16 publications

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“…For these reasons radiochromic film is increasingly used for dosimetry applications. For in vivo dose determina-tions it has been used for skin dose measurements, 72 TSEI measurements, 73,74 and TBI measurements. 75 An implantable type of detector, consisting of a dual MOSFET detector, a data acquisition chip, a microprocessor, and a copper coil, all encapsulated in a glass tube, has been designed to measure in vivo the daily dose delivered to a patient undergoing EBRT.…”

Section: Iib Detectors For Passive In Vivo Dosimetrymentioning

confidence: 99%

In vivo dosimetry in external beam radiotherapy

et al. 2013

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In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20∕20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

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Section: Iib Detectors For Passive In Vivo Dosimetrymentioning

confidence: 99%

In vivo dosimetry in external beam radiotherapy

et al. 2013

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“…The patient immobilization tool was utilized for the positioning of the detector‐phantom system. Application of dosimetry film is also possible for collecting off‐axis data of a large electron field 3 , 8 , 9 , 10 . In Schiapparelli et al, (9) small pieces of radiochromic films were used in a grid arrangement to measure field uniformity on the surface of a plastic pane and for construction of isodose lines in the treatment plane.…”

Section: Introductionmentioning

confidence: 99%

“…Application of dosimetry film is also possible for collecting off‐axis data of a large electron field 3 , 8 , 9 , 10 . In Schiapparelli et al, (9) small pieces of radiochromic films were used in a grid arrangement to measure field uniformity on the surface of a plastic pane and for construction of isodose lines in the treatment plane. With the above‐mentioned methods, the depth of profile measurements is restricted to a specific depth, with the only exception described in the Platoni study, (7) the number of measurement points is limited because of the labor‐intensive nature of such experiments.…”

Section: Introductionmentioning

confidence: 99%

Moving gantry method for electron beam dose profile measurement at extended source‐to‐surface distances

Faludi

Fodor

Pesznyák

2015

J Applied Clin Med Phys

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A novel method has been put forward for very large electron beam profile measurement. With this method, absorbed dose profiles can be measured at any depth in a solid phantom for total skin electron therapy. Electron beam dose profiles were collected with two different methods. Profile measurements were performed at 0.2 and 1.2 cm depths with a parallel plate and a thimble chamber, respectively. 108 cm×108 cm and 45 cm×45 cm projected size electron beams were scanned by vertically moving phantom and detector at 300 cm source‐to‐surface distance with 90° and 270° gantry angles. The profiles collected this way were used as reference. Afterwards, the phantom was fixed on the central axis and the gantry was rotated with certain angular steps. After applying correction for the different source‐to‐detector distances and incidence of angle, the profiles measured in the two different setups were compared. Correction formalism has been developed. The agreement between the cross profiles taken at the depth of maximum dose with the ‘classical’ scanning and with the new moving gantry method was better than 0.5 % in the measuring range from zero to 71.9 cm. Inverse square and attenuation corrections had to be applied. The profiles measured with the parallel plate chamber agree better than 1%, except for the penumbra region, where the maximum difference is 1.5%. With the moving gantry method, very large electron field profiles can be measured at any depth in a solid phantom with high accuracy and reproducibility and with much less time per step. No special instrumentation is needed. The method can be used for commissioning of very large electron beams for computer‐assisted treatment planning, for designing beam modifiers to improve dose uniformity, and for verification of computed dose profiles.PACS numbers: 87.53.Bn, 87.53.Jw, 87.56.jf

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“…7,11,12 Regardless of the specific technique selected for TSET, it is recommended that dose be verified with both phantom and in vivo dosimetry. 11 Ionization chambers, diodes, thermoluminescent dosimeters (TLDs), and radiochromic films are common methods for measuring dose on phantoms or on patients, [12][13][14][15] but these are limited to point or small region measurements. Given the complexity of the treatment area in TSET, these verification tools require a large number of measurements, and careful interpretation is critical.…”

Section: Introductionmentioning

confidence: 99%

Cherenkov imaging method for rapid optimization of clinical treatment geometry in total skin electron beam therapy

et al. 2016

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Purpose: A method was developed utilizing Cherenkov imaging for rapid and thorough determination of the two gantry angles that produce the most uniform treatment plane during dual-field total skin electron beam therapy (TSET). Methods: Cherenkov imaging was implemented to gather 2D measurements of relative surface dose from 6 MeV electron beams on a white polyethylene sheet. An intensified charge-coupled device camera time-gated to the Linac was used for Cherenkov emission imaging at sixty-two different gantry angles (1 • increments, from 239.5• to 300.5 • ). Following a modified Stanford TSET technique, which uses two fields per patient position for full body coverage, composite images were created as the sum of two beam images on the sheet; each angle pair was evaluated for minimum variation across the patient region of interest. Cherenkov versus dose correlation was verified with ionization chamber measurements. The process was repeated at source to surface distance (SSD) = 441, 370.5, and 300 cm to determine optimal angle spread for varying room geometries. In addition, three patients receiving TSET using a modified Stanford six-dual field technique with 6 MeV electron beams at SSD = 441 cm were imaged during treatment. Results: As in previous studies, Cherenkov intensity was shown to directly correlate with dose for homogenous flat phantoms (R 2 = 0.93), making Cherenkov imaging an appropriate candidate to assess and optimize TSET setup geometry. This method provided dense 2D images allowing 1891 possible treatment geometries to be comprehensively analyzed from one data set of 62 single images. Gantry angles historically used for TSET at their institution were 255.5• and 284.5• at SSD = 441 cm; however, the angles optimized for maximum homogeneity were found to be 252.5• and 287.5• (+6 • increase in angle spread). Ionization chamber measurements confirmed improvement in dose homogeneity across the treatment field from a range of 24.4% at the initial angles, to only 9.8% with the angles optimized. A linear relationship between angle spread and SSD was observed, ranging from 35• at 441 cm, to 39• at 300 cm, with no significant variation in percent-depth dose at midline (R 2 = 0.998). For patient studies, factors influencing in vivo correlation between Cherenkov intensity and measured surface dose are still being investigated. Conclusions: Cherenkov intensity correlates to relative dose measured at depth of maximum dose in a uniform, flat phantom. Imaging of phantoms can thus be used to analyze and optimize TSET treatment geometry more extensively and rapidly than thermoluminescent dosimeters or ionization chambers. This work suggests that there could be an expanded role for Cherenkov imaging as a tool to efficiently improve treatment protocols and as a potential verification tool for routine monitoring of unique patient treatments. C

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Total skin electron therapy (TSET): A reimplementation using radiochromic films and IAEA TRS‐398 code of practice

Cited by 18 publications

References 16 publications

In vivo dosimetry in external beam radiotherapy

In vivo dosimetry in external beam radiotherapy

Moving gantry method for electron beam dose profile measurement at extended source‐to‐surface distances

Cherenkov imaging method for rapid optimization of clinical treatment geometry in total skin electron beam therapy

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