No abstract available

[en] As a part of reciprocal inter-Governmental arrangements, Australia hosts regular Governmental-approved peacetime visits of naval vessels. These vessels can be conventionally or nuclear-powered. Because of the nature of Nuclear Powered Warships (NPWs), special procedures have been adopted to ensure that the safety of the general public is maintained during visits by such vessels (Nimitz class carriers or submarines). These procedures include Conditions of Entry and the arrangements for visits, as well as contingency arrangements in the unlikely event of an accident resulting in the hazardous release of radioactivity to the environment. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is involved in an inter-departmental committee, the Visiting Ships Panel (Nuclear) (VSP(N)), which oversees the arrangements for visits to Australian Ports by NPWs. This panel includes representatives from Navy and Jurisdictions which host NPW visits. As well as existing arrangements (including reference accident scenarios and sampling of sediment and local seafood), ARPANSA has initiated programmes to; - Present automated atmospheric dispersion products based on current and predicted weather - these are expected to be housed on a secure web site with outputs tailored to the needs of first responders using the ARGOS decision support tool. - Monitor water concentrations within NPW ports prior to visits, in order to establish baseline values. The monitoring (for Cs-137) involves a high volume filtering and extraction technique which has been developed at ARPANSA and will be discussed. An update on progress will be discussed. This includes an overview of relevant systems, procedures in place and work to be completed. Issues to be resolved and lessons learned will also be considered. (authors)

[en] Wahab et al. (2008) recently published a study using biological dosimetry to estimate doses to New Zealand sailors who were present at the British Grapple Tests in the Pacific 1957-1958. They conclude that elevated translocation frequencies are most likely due to radiation exposure at those tests and doses have been estimated. This assessment of the study by Wahab et al. shows the work has numerous flaws, ignores measured dose information from the test period and the interpretation that sailors were exposed to high radiation doses cannot be sustained by the available data.

[en] A solution for automatic registration of 3D rotational angiography (XA) to CT/MR of the liver. Targeted for use in treatment planning of liver interventions. A shape-based approach to registration is proposed that does not require specification of landmarks nor is it prone to local minima like purely intensity-based registration methods. Through the use of vessel characteristics, accurate registration is possible even in the presence of deformations induced by catheters and respiratory motion. Registration was performed on eight pairs of multiphase CT angiography and 3D rotational digital angiography datasets. Quantitative validation of the registration accuracy using vessel landmarks was performed on these datasets. The validation study showed that the method has a registration error of 9.41±4.13 mm. In addition, the computation time is well below 60 s making it attractive for clinical application. A new method for fully automatic 3DXA to CT/MR image registration was developed and found to be efficient and accurate using clinically realistic datasets. (orig.)

[en] PurposeTo assess feasibility of intraoperative neurophysiologic monitoring (IONM) during image-guided, percutaneous thermal ablation of tumors.Materials and MethodsFrom February 2009 to October 2013, a retrospective review of all image-guided percutaneous thermal ablation interventions using IONM was performed and data was compiled using electronic medical records and imaging studies.ResultsTwelve patients were treated in 13 ablation interventions. In 4 patients, real-time feedback from the monitoring neurologist was used to adjust applicator placement and ablation settings. IONM was technically feasible in all procedures and there were no complications related to monitoring or ablation. All nerves at risk remained intact and of the 11 patients who could be followed, none developed new nerve deficit up to a minimum of 2 months after ablation.ConclusionIONM is safe and feasible for use during image-guided thermal ablation of tumors in the vicinity of nerves. Outcomes in this study demonstrate its potential utility in image-guided ablation interventions.

[en] The purpose of this study was to evaluate computed analysis of three-dimensional (3D) cone-beam computed tomography angiography (CTA) of the liver for determination of subsegmental tumor-feeding vessels (FVs). Eighteen consecutive patients underwent transarterial chemoembolization (TACE) from January to October 2008 for 25 liver tumors (15 hepatocellular carcinomas [HCCs] and 10 neuroendocrine metastases). Anteroposterior projection angiogram (two-dimensional [2D]) and 3D cone-beam CTA images were acquired by injection of the common hepatic artery. Retrospectively, FVs were independently identified by three radiology technologists using a software package (S) that automatically determines FVs by analysis of 3D images. Subsequently, three interventional radiologists (IRs) independently identified FVs by reviewing the 2D images followed by examination of the 3D images. Finally, the 'ground truth' for the number and location of FVs was obtained by consensus among the IRs, who were allowed to use any imaging-including 2D, 3D, and all oblique or selective angiograms-for such determination. Sensitivities, durations, and degrees of agreement for review of 2D, 3D, and S results were evaluated. Sensitivity of 3D (73%) was higher than 2D (64%) images for identification of FVs (P = 0.036). The sensitivity of S (93%) was higher than 2D (P = 0.02) and 3D (P = 0.005) imaging. The duration for review of 3D imaging was longer than that for 2D imaging (187 vs. 94 s, P = 0.0001) or for S (135 s, P = 0.0001). The degree of agreement between the IRs using 2D and 3D imaging were 54% and 62%, respectively, whereas it was 82% between the three radiology technologists using S. These preliminary data show that computed determination of FVs is both accurate and sensitive.

No abstract available

[en] We investigate an optimization-based reconstruction, with an emphasis on image-artifact reduction, from data collected in C-arm cone-beam computed tomography (CBCT) employed in image-guided interventional procedures. In the study, an image to be reconstructed is formulated as a solution to a convex optimization program in which a weighted data divergence is minimized subject to a constraint on the image total variation (TV); a data-derivative fidelity is introduced in the program specifically for effectively suppressing dominant, low-frequency data artifact caused by, e.g. data truncation; and the Chambolle–Pock (CP) algorithm is tailored to reconstruct an image through solving the program. Like any other reconstructions, the optimization-based reconstruction considered depends upon numerous parameters. We elucidate the parameters, illustrate their determination, and demonstrate their impact on the reconstruction. The optimization-based reconstruction, when applied to data collected from swine and patient subjects, yields images with visibly reduced artifacts in contrast to the reference reconstruction, and it also appears to exhibit a high degree of robustness against distinctively different anatomies of imaged subjects and scanning conditions of clinical significance. Knowledge and insights gained in the study may be exploited for aiding in the design of practical reconstructions of truly clinical-application utility. (paper)

[en] The purpose of this report is to introduce a technique of direct lymphangiography to enable chylothorax treatment. Using a hybrid computed tomography (CT) and fluoroscopy imaging system, a 21-gauge needle was placed under CT guidance into the cisterna chyli to allow contrast lymphangiography and CT lymphangiography in two patients with presumed postoperative chylothorax. Water-soluble contrast media injection demonstrated the thoracic duct anatomy in both patients. Further successful needle disruption of the cisterna chyli was performed in one patient to interrupt lymph flow and stop the chylous leak, with subsequent resolution of the chylothorax.

[en] Radiofrequency ablation (RFA) is a well-established method in treatment of patients with lung carcinomas who are not candidates for surgical resection. Usually computed tomographic (CT) guidance is used for the procedure, thus enabling needle placement and permitting evaluation of complications such as pneumothorax and bleeding. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is generally used for tumor activity assessment and is therefore useful in follow-up after tumor treatment. A method that provides real-time image-based monitoring of RFA to ensure complete tumor ablation would be a valuable tool. In this report, we describe the behavior of preinjected FDG during PET CT–guided RFA of a non-small-cell lung carcinoma and discuss the value of FDG as a tool to provide intraprocedure monitor ablation. The size and the form of the activity changed during ablation. Ablation led to increase of the size and blurring and irregularity of the contour compared to pretreatment imaging. The maximal standardized uptake value decreased only slightly during the procedure. Therefore, before RFA, FDG PET can guide initial needle placement, but it does not serve as a monitoring tool to evaluate residual viable tissue during the procedure.