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Ebstein's anomaly of the tricuspid valve (TV) is a congenital cardiac malformation of the tricuspid valve (TV) and right ventricle (RV) characterized by downward displacement of the functional annulus usually involving septal and inferior leaflets. Ebstein's anatomical spectrum is highly variable. This anatomical study aimed to unravel the morphogenetic mechanisms underlying this variability. Forty-two hearts exhibiting Ebstein anomaly from the Reference Center for Complex Congenital Heart Defects (CHD) collection were macroscopically analysed: 28 isolated and 14 associated with another CHD. Tricuspid leaflets, right ventricle (RV), and associated lesions were analysed. Measurements were related to fetal heart reference values according to gestational age. Specimens were classified depending on the distal insertion of the anterior leaflet: linear, hyphenated or focal. Among isolated Ebstein hearts, distal insertion of the anterior leaflet was linear in 36%, hyphenated in 29% and focal in 36%. Linear insertion was always associated with anterior TV orifice and absent inferior leaflet, with absent septal leaflet in 80%. Atrialisation (thin, paper-like, inferior RV wall) was found in 90% of the linear forms and 37.5% of the hyphenated forms, which were associated with various degrees of inferior and septal leaflets non-delaminationanomalies. In focal forms, only the septal leaflet was involved, and there was no atrialisation. Ventricular septal defect was found in 3 specimens, Uhl-like RV anterior wall in 2, including 1 with left ventricle non compaction. Associated Ebstein anomalies were predominantly found in pulmonary atresia with intact ventricular septum; there was no atrialisation and septal leaflet only was involved. Ebstein anomaly corresponds to an arrest in TV development, early in linear forms, late in focal forms, intermediate in hyphenated forms. Atrialisation was always associated with absent inferior leaflet, underlining developmental interaction between endocardial cushions and myocardium at the RV inferior wall. [ABSTRACT FROM AUTHOR]

Pulmonary atresia with intact ventricular septum (PA-IVS) means pulmonary valvar atresia without a ventricular septal defect (VSD). In PA-IVS, the right ventricle (RV) appears externally normal in size but the internal cavity is hypoplastic with major wall hypertrophy. Histology reveals myocardial disarray and endocardial fibroelastosis. The leaflets of the pulmonary valve are present but fused indicating an acquired lesion during fetal life. The files of all children with PA-IVS in our institution between 1981 and 2023 were reviewed, using a data warehouse to look for associated VSD. Patients with Ebstein anomaly and pulmonary atresia were excluded. When available, echocardiographic examinations were reviewed. One patient had severe coronary arterial anomaly leading to death and autopsy. The total cohort included 300 consecutive patients. Among those, we found 8 children with an associated VSD (2.6% of the cohort). According to the IPCCC-ICD11 nomenclature, the VSD was central perimembranous in 3, muscular in 4, outlet in 1. In this last patient, autopsy revealed a hypoplastic but not malaligned outlet septum, without aortic overriding, which discarded the diagnosis of tetralogy of Fallot (Fig. 1). Paradoxically, the presence of a VSD is compatible with diagnosis of PA-IVS. This rare association cannot be classified as "PA-VSD": this last term should be reserved to extreme forms of tetralogy of Fallot, associating outlet VSD, anteriorly malaligned outlet septum, overriding aorta and PA. Conversely, PA-IVS may be due to a RV myocardial disease, leading to a diminutive RV cavity, tricuspid valve hypoplasia and progressive fusion of the pulmonary leaflets leading to atresia. The anatomic type of VSD, muscular and perimembranous, and their rarity, are in favor of an incidental association. The imprecise term "PA-IVS" does not reflect the defect's anatomy and pathogenesis. It should then be modified, as it is crucial to use an accurate terminology to better describe congenital heart defects. [ABSTRACT FROM AUTHOR]

Purpose This study aims at characterising the properties of TruView™ and ClearView™ two new gel dosimeters (Modus Medical Devices Inc.) and at studying the feasibility of relative dosimetry using these dosimeters and the Vista™ Optical CT scanner to accurately evaluate dose. Methods In this work, we investigated key dosimetric aspects (dose response, energy and dose rate dependence) and stability of these radiochromic gels initiated in preliminary works (Huet et al., 2017; Colnot et al., 2017) using spectrophotometric measurements. Moreover, by mean of optical CT scanning (Vista™), their performances to measure relative depth dose (PDD) and cross profiles were analysed. Results TruView™ and ClearView™ present a linear dose response up to 20 Gy and up to 80 Gy respectively, independent of both photon beam energy (4–18 MV) and dose rate (up to 9.9 Gy/min) (Huet et al., 2017; Colnot et al., 2017). ClearView™ response proves to be stable for a week post-irradiation and uniform within the batch whereas TruView™ presents an unstable but uniform response. Optical CT scanning generates errors due to stray light that need to be corrected in order to use these gels; ClearView™ scanning particularly requires important precautions. After corrections, those gels used in combination with the Vista™ scanner show promising spatial and dosimetric precision (dose difference <5%). Finally, TruView™ is reusable and presents excellent reproducible response (maximum 3% difference) and the ClearView™ dosimeter presents good spatial stability (0.5% difference after 6 days). Conclusion This study provides important knowledge about two gel dosimeters presenting interesting dosimetric properties. A study is ongoing to benchmark those promising candidates for clinical dose verification. [ABSTRACT FROM AUTHOR]

Gafchromic™ films have become popular due to their ease of use and their near water equivalence. This last property is crucial for stereotactic small beam dosimetry as demonstrated in recent papers. An accurate bi-dimensional dose measurement with Gafchromic™ films is very challenging mainly because of the non-uniformity response of flatbed scanners (used for films digitalization) and their own non-uniformity. The first proposal of this work is to develop bi-dimensional protocol for small beams and evaluate the associated uncertainty. The second proposal is to validate this protocol for the bi-dimensional measurements of treatment plans performed with the CyberKnife ® system. First, the uniformity of an Epson V700 flatbed scanner and a batch of EBT3 Gafchromic™ films has been investigated. A “four films” dosimeter was designed to reduce the errors (statistic and systematic) due to their non-uniformity. Then, the “four films” dosimeter protocol in both a homogeneous (RW3 material) and heterogeneous (RW3, lung-like and bone-like materials) phantoms has been used to measure the bi-dimensional dose distributions of three simple CyberKnife ® treatment plans. Two tumor locations (middle of the lung and near lung/bone interface) were considered for the heterogeneous phantom. These plans were achieved with the 10 mm fixed collimator and modeled with the PENELOPE Monte Carlo code in order to calculate accurate dose distributions. Finally, the “four films” bi-dimensional dose distributions were compared to the PENELOPE Monte Carlo simulations. Regarding the uncertainty associated to the bi-dimensional dose measurement protocol, the relative standard deviation σ D on the dose was 1.2% in the range from 0.5 to 4.0 Gy. Regarding the protocol validation on CyberKnife ® treatment plans, a very good agreement was found with all measurement points passing the {3% - 3 mm} Gamma Index criteria. [ABSTRACT FROM AUTHOR]

Radiochromic film dosimetry is a promising technique, but at this time there are some artefacts, including non-uniformity, energy dependence and scanner artefacts. Accurate dosimetry with radiochromic films requires characterizing the film as well as the scanning and analysis procedures. In this work, the performance of the EBT3 films in combination with the EPSON Dual Lens Perfection V700 scanner for dose distribution measurements in stereotactic radiotherapy has been evaluated. It has been shown that it was necessary to perform 20 blank scans to obtain the stability of the scanner. In order to reduce the uncertainties due to the non-uniformity of the scan field, it was then decided to use the 12 × 12 cm 2 central part of the scanner bed. Regarding EBT3 films, intra-sheet and inter-sheet uniformity of unexposed EBT3 films in terms of pixel value has been found to be respectively 0.27% (1 SD) and 0.15% (1 SD). No significant energy dependence has been observed above 30 keV and no angular dependence has been found. [ABSTRACT FROM AUTHOR]

A new formalism for small field dosimetry has been proposed ( Alfonso et al., 2008 ) with the concept of an additional correction factor ( k Q clin , Q msr f clin , f msr ) which accounts for possible changes in detector response with field size. The aim of this work was to evaluate the response of eight commercially available detectors, then to provide a set of correction factors for a 1000 MU/min CyberKnife ® equipped with fixed collimators and to compare them with those obtained for the 800 MU/min CyberKnife ® version. Measurements were performed on a 1000 MU/min CyberKnife ® with several active detectors designed for small field dosimetry (two chambers (PTW 31014 and 31018), three high resolution diodes (PTW 60016, 60017 and Sun Nuclear EDGE), a natural diamond (PTW 60003)) and two passive dosimeters (Harshaw TLD-700 7 LiF:Mg,Ti thermoluminescent micro-cube and EBT3 radiochromic films). The CyberKnife ® as well as the diode detectors, the PinPoint chamber, the diamond and the LiF micro-cubes were modeled with the PENELOPE Monte Carlo code in order to calculate the output factors in a point-like voxel of water (OF MC,w ). A set of k Q clin , Q msr f clin , f msr correction factors for the active detectors investigated is provided for the 1000 MU/min CyberKnife ® in order to be used with the new formalism. A difference up to 2.4%, 2.0 and 1.7% in the correction factor obtained for the two different CyberKnife ® models is found for the PTW 60003, the PTW 60016 and the PTW 60017 respectively. Although this difference is small, we recommend using specific k Q clin , Q msr f clin , f msr correction factors for the 1000 MU/min CyberKnife ® when they are available. [ABSTRACT FROM AUTHOR]

Abstract: The accurate determination of absorbed dose in small photon beams, especially for stereotactic radiation therapy, is a difficult task with commercially available detectors. As these small fields are characterized by high dose gradients, a lack of lateral particle equilibrium and a variation of energy spectra with beam sizes, a dosimeter with high resolution, tissue-equivalence and high precision is required. The new radiochromic film EBT2, which meets these criteria, was fully characterized in Institut de Radioprotection et Sûreté Nucléaire (IRSN) for this application. This type of film was tested with the reading system EPSON Dual Lens Perfection V700 flatbed scanner in transmission mode. Warm-up effects of the scanner were studied as well as the influence of the scanner light. Uniformity of unirradiated and irradiated EBT2 films in terms of pixel value was found to be respectively 0.3% (1 SD) and 0.5% (1 SD). An original, accurate and efficient radiochromic film dosimetry protocol was established. The overall uncertainty for dose measurement with EBT2 films using this protocol was estimated at less than 2% (1 SD). Encouraging measurements of output factors were performed on a Novalis system. [Copyright &y& Elsevier]

Abstract: The dosimetry of the experimental reactor CALIBAN was established for photon and neutron components, and the kerma variations were evaluated according to position (distance from the core, height, angle with the median room axis). Dosimetry was performed with TLD (Al2O3) for the photon component, and with passive silicon diodes, activation detectors (Au, In, Ni, Mg, Cu) and alanine pellets measured by EPR spectrometry for the neutron component. The neutron energy distribution was experimentally evaluated at various distances based on the activities measured at the activated foil using the SNAC2 software. It was then compared with those calculated with the Monte Carlo code MCNPX. [Copyright &y& Elsevier]

Abstract: Following a radiological accident on 11 March 2006 in an industrial irradiation facility involving one victim, a physical dosimetry was reconstructed using on site measurements and numerical simulations in order to estimate as accurately as possible and as quickly as possible the dose received and its distribution throughout the organism so that doctors may fine tune their diagnosis and prescribe the most suitable treatment. The data compiled from the experimental reconstruction resulted in a first estimation of the distribution of the dose in the victim''s organism. The numerical simulations indicated a dose gradient corresponding to a factor of 2 in anteroposterior and between the pelvis and the skull. [Copyright &y& Elsevier]

Abstract: A severe irradiation accident, due to gammagraphy equipment containing an 192Ir radioactive source, involving several victims occurred from the 3 June to 3 August 2006 in two African subsidiaries of the French group Bureau Veritas. This article retraces the circumstances of the accident and the physical dosimetric reconstruction made by IRSN on four patients treated in France. The dose reconstruction was based on numerical simulations and electron paramagnetic resonance (EPR) measurements performed on bone tissue and tooth enamel samples. The data obtained by physical dosimetry, as complementary elements to biological dosimetry and clinical observations, were helpful for the treatment strategy implemented by the medical team. [Copyright &y& Elsevier]

An intercomparison exercise is described that examines Monte Carlo modelling of anthropomorphic voxel phantoms in an idealized ground-contamination photon exposure scenario. Thirteen participants calculated and submitted organ and effective dose rates for comparison against a set of verified reference solutions. The effective dose rates are shown to agree with the reference value to within reasonable statistical uncertainties in five of the cases, though in only one of those was similar agreement also demonstrated in the evaluation of all requested organ dose rates. Orders-of-magnitude differences in doses are seen for some of the other participants, both internally within their own dataset and also relative to the reference solutions. Following limited feedback and suggestions from the organizer, up to two sets of revised solutions were resubmitted by some of the participants; these generally exhibited improved agreement, though not always. The overall observations and conclusions from this intercomparison exercise are summarized and discussed. • Presentation of an intercomparison exercise on Monte Carlo modelling of anthropomorphic voxel phantoms. • An idealized ground-contamination photon exposure scenario was proposed. • Thirteen participants submitted organ and effective dose rates for comparison against verified reference solutions. • Effective dose rates appeared to agree with the reference value in five of the cases. • In only one of those cases was similar agreement also demonstrated in the evaluation of all requested organ dose rates. • Orders-of-magnitude differences in doses were seen for some of the participants. • The overall observations and conclusions from the exercise are summarized and discussed. [ABSTRACT FROM AUTHOR]

Introduction Cutting-edge radiotherapy techniques deliver highly conformal treatments with steep dose gradients around the target volume. Thus, the verification of the complex resultant dose distributions presents a real dosimetric challenge requiring accurate and spatially precise dosimeters. Gel dosimetry is a promising technique as it can inform about the whole 3-D dose distribution in one irradiation and without conventional dosimeters issues [1] . This study focuses on the characterisation of the new TruView™ gel dosimeter (Modus Medical Devices Inc.). This dosimeter is based on Fricke-MTB composition [2] but presents a new MethylThymol Blue (MTB) reactive dye and a reusable structure. The dosimetric properties of this gel dosimeter and the influence of different parameters on its response are presented. Methods The key dosimetric aspects (dose response, dependence with energy and dose rate) and the TruView™ dosimeter variability with different parameters (gel temperature, light exposure, time between irradiation and reading, etc.) were studied thanks to spectrophotometric measurements. Finally, by mean of optical CT scanning (Vista™, Modus Medical Devices Inc.), its performances to measure relative depth dose (PDD) and cross profiles have been analysed. Results TruView™ presents linear response with dose up to 20 Gy independent of both photon beam energy and dose rate on the studied ranges. The study of the numerous parameters influencing its dose response enabled to determine the optimal conditions for using this gel. In those conditions, the comparison of TruView™ relative depth dose (PDD) and of cross profiles with ion chamber measurements shows a good dosimetric and spatial precision with 90% of the points passing the 3 mm 3% gamma test for the PDD and 87% for the cross profiles. Seven days after irradiation, ion diffusion inside the gel leads to return to homogeneity allowing a new irradiation to be performed. The TruView™ response presents an excellent reproducibility as 100% of the points pass the gamma test for the comparison between the PDD of the two uses and 94% for the cross profiles. Conclusions This study provides important knowledge regarding the 3-D gel dosimeter TruView™. This dosimeter presents interesting dosimetric properties but remains delicate to use due to the great response sensitivity to numerous parameters. A further study is currently ongoing to benchmark this promising candidate for clinical dose verification. [ABSTRACT FROM AUTHOR]

Introduction Recently, cancer treatment improvement enabled an increase in patients' survival rate. In more than half of the cases, radiotherapy participates in the cure for cancer. The efficacy of this technique is well known but it inevitably delivers doses to normal tissues exposing them to radio-induced complications risks [1]. Moreover, the longer patients' life expectancy increases the risk of developing long-term complications such as second cancers. Thus, evaluating the risks following cancer treatment involving radiotherapy constitutes a major challenge. In this context, an experimental tool has been developed to evaluate normal tissue doses delivered by the different radiotherapy techniques. Those dosimetric data are prerequisites for risk evaluation. Methods The tool developed on Matlab is based on 3D dose reconstruction from 2D dose measurements performed using radiochromic films placed between phantom slices. The tool proceeds to fine spatial films/TPS dose matching near the target volume and then reconstructs the 3D dose distribution by interpolation of films dose measurements. Finally, interesting dosimetric data such as dose-volume histograms are evaluated. A first validation of the tool has been performed with the EasyCube phantom irradiated with two films spaced 2 cm apart and placed in target volume. After scanning and contouring, the phantom was irradiated according to a treatment planning with the films in place. Films were analyzed using a rigorous protocol [2] developed by our group. Results Both 2D and volumetric comparisons between measured and planned doses gave good results. Indeed, 89.2% of points pass the 3 mm/3% gamma test when comparing interpolated dose distribution and planned dose on the middle slice. Likewise, a 2.6% discrepancy on mean PTV doses has been observed between the two distributions and the mean shift between the 0.4 Gy isodoses is of 0.10 mm on the middle slice. Conclusions The original tool developed in this work enables an experimental evaluation of normal tissue doses: essential dosimetric data for risk evaluation models. The preliminary feasibility study shows promising results. Validation and optimization on a more important volume is currently ongoing. Finally, validation using 3D gel dosimetry is considered. [ABSTRACT FROM AUTHOR]

The purpose of this work is to assess the feasibility of performing dosimetry with the TruView (ModusQA, London, Ontario, Canada) MTB Fricke gel by MRI reading on a low field MR-Linac (0.35 T). Radiochromic TruView gels were manufactured at IRSN. A 4 echoes time (TE) single-shot fast spin echo sequence (HASTE) was used for 2D images acquisitions. Raw MRI images were denoised (MP-PCA) and transversal relaxation rates (R2) maps were extracted using a homemade Matlab routine. Temperature influences on R2 as well as gel homogeneity were investigated. A dosimetric evaluation of the TruView gel was conducted implying four gels made from the same batch, with three of them dedicated to calibration, and the fourth one received a simple dosimetric plan. Results showed the TruView gel to be sensitive to temperature drift. A protocol was thus developed to ensure thermal stability with the use of a dedicated temperature-controlled water bath. An inhomogeneity that manifests as a R2 increase near the air/gel interface was found to cause a 4% amplitude deviation in R2 along unirradiated gels. Air sealing drastically reduced the inhomogeneity. Dose versus R2 calibration was established. TruView gel sensitivity was found to be low (0.0093 Gy−1 s−1). 1D and 2D comparison to planned dose distribution displayed overall agreement with global gamma index (5%/3 mm) evaluation with an 87 % passing rate. Main discrepancies in the low and gradient dose regions were attributable to the calibration range and diffusion effects. This study demonstrated the feasibility of using the TruView gel for dosimetric evaluation on a low field MR-Linac. The protocol developed needs to be extended to a full 3D evaluation to enable patient QA and may require modifications to the gel formulation to increase its overall sensitivity and ensure limited dependence on temperature drift. • Dosimetry using the TruView Fricke gel, MRI reading on a low-field MR-Linac (0.35 T). • Use of fast MRI sequence (HASTE) for dosimetric evaluations. • Temperature drift and inhomogeneity in the gels, low R2-Dose sensitivity. • Stabilization protocol for the TruView gel to ensure reliable dosimetric evaluations. • TruView gel suitable for dosimetric evaluation, full 3D validation is needed. [ABSTRACT FROM AUTHOR]

Several passive solid state dosemeters, such as Gafchromic™ films and thermoluminescence (TL) detectors, are used to estimate and monitor patient skin doses in interventional radiology. To determine the suitability of XR-TypeR Gafchromic™ films and of detectors based on TL materials: pellets, chips and foils to measure skin dose, an intercomparison exercise has been organized within European Dosimetry Radiation Group – Working Group 12 “European Medical ALARA Network” (EURADOS WG12). To test response detectors were exposed to X-ray beams of energies and qualities applied clinically. A blind test was also performed to investigate the accuracy of the dose estimate by detectors exposed to unknown doses. We found the response of films to be strongly dependent on beam quality and filtration (increasing by up to 80% with respect to reference beam quality). The response of TL detectors was found to be less dependent on beam quality (less than 25% variation), with TL foils showing less than 10% variation with respect to reference beam quality. To accurately estimate patient skin doses in interventional radiology it is important to choose the quality of the calibration beam to be as close as possible to the quality of beams actually applied in clinical work. [ABSTRACT FROM AUTHOR]