Arms down cone beam CT hepatic angiography: are we focusing on the wrong target?

We read with great interest the recent article by Dr. Gonzalez-Aguirre and colleagues entitled ‘‘Arms Down Cone Beam CT Hepatic Angiography Performance Assessment: Vascular Imaging Quality and Imaging Artefacts’’ [1]. One of the most important advantages of cone beam CT (CBCT) is the possibility to evaluate the lesion’s feeders assisting their identification and catheterization [2]. In this set, the patient’s arms positioning is crucial in order not to impair CBCT imaging. Dr. Gonzalez-Aguirre et al. had elegantly demonstrated that vessels’ visualization is independent from the patient’s arms position, allowing to perform the entire procedure without patient’s movements. This minimizes the risk of contamination and reduces procedural time. However, literature shows that the major pivotal strength of CBCT, either mono-phasic or possibly bi-phasic, is the ability to depict in intra-procedurally ‘‘occult lesions’’, not visible at pre-procedural second-line non-invasive imaging (MRI, MDCT) [3]. This ability is not just for show, but yield to some major clinical implications: the visualization of an occult nodule identifies a subset of population experiencing fast tumour growth, having consequences on the number of adjunctive treatments controlling tumour growth (adjunctive RFA, or TACE procedures) and prioritization for transplantation [4]. Moreover, bi-phasic CBCT, with its unique ability to intra-procedural permit nodule characterization, could help in patients’ reclassification and real-time TACE strategy modification [5]. In this light would be a crucial interest for the audience to know whether the CBCT acquisition with arms down does not alter the diagnostic performance of the modality and ability of lesion’s characterization, especially for those lesion localized peripherally, where the beam hardening artefacts have been shown to be significant. Finally, patient’s positioning is fundamental for CBCT imaging. By acquiring the scan with patient’s arm down, liver volume would not be located within the rotation isocentre. This could be a substantial limitation for lesion located within the left liver lobe, eventually hypertrophied, and for high BMI patients

Neutron spectrometer for fast nuclear reactors

In this paper we describe the development and first tests of a neutron spectrometer designed for high flux environments, such as the ones found in fast nuclear reactors. The spectrometer is based on the conversion of neutrons impinging on $^6$Li into $\alpha$ and $t$ whose total energy comprises the initial neutron energy and the reaction $Q$-value. The $^6$LiF layer is sandwiched between two CVD diamond detectors, which measure the two reaction products in coincidence. The spectrometer was calibrated at two neutron energies in well known thermal and 3 MeV neutron fluxes. The measured neutron detection efficiency varies from 4.2$\times 10^{-4}$ to 3.5$\times 10^{-8}$ for thermal and 3 MeV neutrons, respectively. These values are in agreement with Geant4 simulations and close to simple estimates based on the knowledge of the $^6$Li(n,$\alpha$)$t$ cross section. The energy resolution of the spectrometer was found to be better than 100 keV when using 5 m cables between the detector and the preamplifiers.Comment: submitted to NI

The Offline Software Framework of the Pierre Auger Observatory

The Pierre Auger Observatory is designed to unveil the nature and the origins of the highest energy cosmic rays. The large and geographically dispersed collaboration of physicists and the wide-ranging collection of simulation and reconstruction tasks pose some special challenges for the offline analysis software. We have designed and implemented a general purpose framework which allows collaborators to contribute algorithms and sequencing instructions to build up the variety of applications they require. The framework includes machinery to manage these user codes, to organize the abundance of user-contributed configuration files, to facilitate multi-format file handling, and to provide access to event and time-dependent detector information which can reside in various data sources. A number of utilities are also provided, including a novel geometry package which allows manipulation of abstract geometrical objects independent of coordinate system choice. The framework is implemented in C++, and takes advantage of object oriented design and common open source tools, while keeping the user side simple enough for C++ novices to learn in a reasonable time. The distribution system incorporates unit and acceptance testing in order to support rapid development of both the core framework and contributed user code.Comment: 4 pages, 2 figures, presented at IEEE NSS/MIC, 23-29 October 2005, Puerto Ric

Super selective arterial embolization to treat radiation-induced hemorrhagic gastritis: a case report and review of the literature

Radiation-induced hemorrhagic gastritis (RIHG) is a rare but potentially fatal event following radiotherapy for locally advanced gastric cancer; the treatment of this condition is not standardized. Only few cases of RIHG have been reported, treated with different therapeutic approaches. Here we report the case of a 79-year-old patient who underwent subtotal gastrectomy for gastric cancer, followed by adjuvant chemo-radiotherapy. Approximately 3 months after the end of the treatment, she developed recurrent diffuse bleeding originating from the entire mucosa of the gastric pouch and from a marginal ulcer. As the bleeding was refractory to several endoscopic treatments and surgery was not indicated, the patient underwent two sessions of transcatheter selective arterial embolization, with resolution of bleeding. Arterial embolization has already been reported for the treatment of hemorrhagic cystitis, developing after irradiation of the pelvis for prostate, bladder, rectum, and cervix cancer. However, to our knowledge, it has never been reported as a treatment for hemorrhagic gastritis. Based on this case, we suggest arterial embolization as an option in the management of RIHG, when standard endoscopic treatment fails

The Offline Software Framework of the Pierre Auger Observatory

To be published in the ProceedingsInternational audienceThe Pierre Auger Observatory is designed to unveil the nature and the origins of the highest energy cosmic rays. The large and geographically dispersed collaboration of physicists and the wide-ranging collection of simulation and reconstruction tasks pose some special challenges for the offline analysis software. We have designed and implemented a general purpose framework which allows collaborators to contribute algorithms and sequencing instructions to build up the variety of applications they require. The framework includes machinery to manage these user codes, to organize the abundance of user-contributed configuration files, to facilitate multi-format file handling, and to provide access to event and time-dependent detector information which can reside in various data sources. A number of utilities are also provided, including a novel geometry package which allows manipulation of abstract geometrical objects independent of coordinate system choice. The framework is implemented in C++, and takes advantage of object oriented design and common open source tools, while keeping the user side simple enough for C++ novices to learn in a reasonable time. The distribution system incorporates unit and acceptance testing in order to support rapid development of both the core framework and contributed user code

Fetal alcohol spectrum disorder and youth justice: a prevalence study among young people sentenced to detention in Western Australia

Objectives: To estimate the prevalence of fetal alcohol spectrum disorder (FASD) among young people in youth detention in Australia. Neurodevelopmental impairments due to FASD can predispose young people to engagement with the law. Canadian studies identified FASD in 11%–23% of young people in corrective services, but there are no data for Australia. Design: Multidisciplinary assessment of all young people aged 10–17 years 11 months and sentenced to detention in the only youth detention centre in Western Australia, from May 2015 to December 2016. FASD was diagnosed according to the Australian Guide to the Diagnosis of FASD. Participants: 99 young people completed a full assessment (88% of those consented; 60% of the 166 approached to participate); 93% were male and 74% were Aboriginal. Findings: 88 young people (89%) had at least one domain of severe neurodevelopmental impairment, and 36 were diagnosed with FASD, a prevalence of 36% (95% CI 27% to 46%). Conclusions: This study, in a representative sample of young people in detention in Western Australia, has documented a high prevalence of FASD and severe neurodevelopmental impairment, the majority of which had not been previously identified. These findings highlight the vulnerability of young people, particularly Aboriginal youth, within the justice system and their significant need for improved diagnosis to identify their strengths and difficulties, and to guide and improve their rehabilitation

The impact of field size and radiation quality on KAP-meter and CT-chamber response

Kerma-area product and kerma-length product are important practical dosimetric quantities used in diagnostic radiology. These quantities are measured by special types of dosimeters which are calibrated in standard radiation qualities established in calibration laboratories. However, in clinical practice the dosimeters are used in different conditions, including the radiation quality and field size. In this paper, energy and field size dependence are studied for both types of dosimeters. One dosimeter of each type is tested. The KAP-meter has shown significant dependence on both radiation quality and field size, while the dependence of the CT-chamber is much less pronounced. Two different approaches can be used to correct for the difference between conditions during calibration and in clinical practice. When the clinical beam is well characterized and energy and field size dependence of the dosimeter are well known, the optimum solution is to apply the adequate correction factor to the measurements, keeping measurement uncertainty as low as possible. If this is not the case, the above limitations must be taken under consideration in the calculation of the expanded uncertainty budget