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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]

Recent use of very small photon beams (down to 4 mm) in stereotactic radiotherapy requires new detectors to accurately determine the delivered dose. Diamond detectors have been presented in the literature as an attractive candidate for this application, due to their small detection volume and the diamond atomic number (Z=6) which is close to water effective atomic number (Zeff∼7.42). However, diamond exhibits a density 3.51 times greater than that of water and recent studies using Monte Carlo simulations have demonstrated the drawback of a high-density detector on small beam output factors. The current study focuses on geometrical parameters of diamond detector, namely, the diamond dimensions and the electrode geometry, in order to solve the dosimetric issues still observed in small photon beams with diamond detectors. To give better insights to these open questions, we have used both computational method and experimental analysis. This study highlighted that reducing diamond dimensions is crucial for small beam output factor measurements and to limit the influence of its high density. Furthermore, electrodes covering the whole diamond surface were essential for a dose rate independence of the diamond detector. The optimal dosimeter derived from this work presented small diamond dimensions of approximately 1-1-0.15mm3, with diamond-like-carbon electrodes covering the whole diamond surface. A dose rate independence of this diamond detector (better than 0.5% over a wide range of dose rates available on a stereotactic dedicated facility) was obtained due to the electrode geometry. Concerning the output factor measurements, a good agreement (better than 1.1%) was observed between this carbon material detector and two types of passive dosimeters (LiF microcubes and EBT2 radiochromic films) for all beam sizes except the smallest field of 0.6-0.6 cm2 with a deviation of 2.6%. This new study showed the high performance of this diamond detector in small photon beams, in comparison with various commercially available passive and active dosimeters. [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]

The structural transformations induced in Gd2O3 and Eu2O3 irradiated with high-energy ions (94-MeV Pb and 1042-MeV Xe), where ionization processes (electronic stopping) dominate the ion slowing-down, have been studied via the combination of XRD and Raman experiments. Irradiation induces a cubic-to-monoclinic phase transformation; the radiation-induced monoclinic phase shows strong preferential orientation. This structural modification is accompanied by changes in the photoluminescence properties of sesquioxides. The results show that swift heavy ion irradiation is a powerful tool to control the properties of oxides at the nanoscale. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the optimal use of XR-RV3 GafChromic® films to assess patient skin dose in interventional radiology while addressing the means to reduce uncertainties in dose assessment. Methods: XR-Type R GafChromic films have been shown to represent the most efficient and suitable solution to determine patient skin dose in interventional procedures. As film dosimetry can be associated with high uncertainty, this paper presents the EURADOS WG 12 initiative to carry out a comprehensive study of film characteristics with a multisite approach. The considered sources of uncertainties include scanner, film, and fitting-related errors. The work focused on studying film behavior with clinical high-dose-rate pulsed beams (previously unavailable in the literature) together with reference standard laboratory beams. Results: First, the performance analysis of six different scanner models has shown that scan uniformity perpendicular to the lamp motion axis and that long term stability are the main sources of scanner-related uncertainties. These could induce errors of up to 7% on the film readings unless regularly checked and corrected. Typically, scan uniformity correction matrices and reading normalization to the scanner-specific and daily background reading should be done. In addition, the analysis on multiple film batches has shown that XR-RV3 films have generally good uniformity within one batch (<1.5%), require 24 h to stabilize after the irradiation and their response is roughly independent of dose rate (<5%). However, XR-RV3 films showed large variations (up to 15%) with radiation quality both in standard laboratory and in clinical conditions. As such, and prior to conducting patient skin dose measurements, it is mandatory to choose the appropriate calibration beam quality depending on the characteristics of the x-ray systems that will be used clinically. In addition, yellow side film irradiations should be preferentially used since they showed a lower dependence on beam parameters compared to white side film irradiations. Finally, among the six different fit equations tested in this work, typically used third order polynomials and more rational and simplistic equations, of the form dose inversely proportional to pixel value, were both found to provide satisfactory results. Fitting-related uncertainty was clearly identified as a major contributor to the overall film dosimetry uncertainty with up to 40% error on the dose estimate. Conclusions: The overall uncertainty associated with the use of XR-RV3 films to determine skin dose in the interventional environment can realistically be estimated to be around 20% (k = 1). This uncertainty can be reduced to within 5% if carefully monitoring scanner, film, and fitting-related errors or it can easily increase to over 40% if minimal care is not taken. This work demonstrates the importance of appropriate calibration, reading, fitting, and other film-related and scan-related processes, which will help improve the accuracy of skin dose measurements in interventional procedures. [ABSTRACT FROM AUTHOR]

Purpose: In a previous work, output ratio (ORdet) measurements were performed for the 800 MU/min CyberKnife ® at the Oscar Lambret Center (COL, France) using several commercially available detectors as well as using two passive dosimeters (EBT2 radiochromic film and micro-LiF TLD-700). The primary aim of the present work was to determine by Monte Carlo calculations the output factor in water (OFMC,w) and the kQclin,Qmsrfclin,fmsr correction factors. The secondary aim was to study the detector response in small beams using Monte Carlo simulation. Methods: The LINAC head of the CyberKnife R ® was modeled using the PENELOPE Monte Carlo code system. The primary electron beam was modeled using a monoenergetic source with a radial gaussian distribution. The model was adjusted by comparisons between calculated and measured lateral profiles and tissue-phantom ratios obtained with the largest field. In addition, the PTW 60016 and 60017 diodes, PTW 60003 diamond, and micro-LiF were modeled. Output ratios with modeled detectors (ORMC,det) and OFMC,w were calculated and compared to measurements, in order to validate the model for smallest fields and to calculate kQclin,Qmsrfclin,fmsr correction factors, respectively. For the study of the influence of detector characteristics on their response in small beams; first, the impact of the atomic composition and the mass density of silicon, LiF, and diamond materials were investigated; second, the material, the volume averaging, and the coating effects of detecting material on the detector responses were estimated. Finally, the influence of the size of silicon chip on diode response was investigated. Results: Looking at measurement ratios (uncorrected output factors) compared to the OFMC,w, the PTW 60016, 60017 and Sun Nuclear EDGE diodes systematically over-responded (about +6% for the 5 mm field), whereas the PTW 31014 Pinpoint chamber systematically under-responded (about -12% for the 5 mm field). ORdet measured with the SFD diode and PTW 60003 diamond detectors were in good agreement with OFMC,w except for the 5 mm field size (about -7.5% for the diamond and +3% for the SFD). A good agreement with OFMC,w was obtained with the EBT2 film and micro- LiF dosimeters (deviation less than 1.4% for all fields investigated). kQclin,Qmsrfclin,fmsrcorrection factors for several detectors used in this work have been calculated. The impact of atomic composition on the dosimetric response of detectors was found to be insignificant, unlike the mass density and size of the detecting material. Conclusions: The results obtained with the passive dosimeters showed that they can be used for small beam OF measurements without correction factors. The study of detector response showed that ORdet is depending on the mass density, the volume averaging, and the coating effects of the detecting material. Each effect was quantified for the PTW 60016 and 60017 diodes, the micro- LiF, and the PTW 60003 diamond detectors. None of the active detectors used in this work can be recommended as a reference for small field dosimetry, but an improved diode detector with a smaller silicon chip coated with tissue-equivalent material is anticipated (by simulation) to be a reliable small field dosimetric detector in a nonequilibrium field. [ABSTRACT FROM AUTHOR]