The role of intraoperative hyperspectral imaging (HSI) in colon interposition after esophagectomy.

Background: Colon conduit is an alternative approach to reconstructing the alimentary tract after esophagectomy. Hyperspectral imaging (HSI) has been demonstrated to be effective for evaluating the perfusion of gastric conduits, but not colon conduits. This is the first study to describe this new tool addressing image-guided surgery and supporting esophageal surgeons to select the optimal colon segment for the conduit and anastomotic site intraoperatively.

Fluorescent analogs of peptoid-based HDAC inhibitors: Synthesis, biological activity and cellular uptake kinetics.

Fluorescent tagging of bioactive molecules is a powerful tool to study cellular uptake kinetics and is considered as an attractive alternative to radioligands. In this study, we developed fluorescent histone deacetylase (HDAC) inhibitors and investigated their biological activity and cellular uptake kinetics. Our approach was to introduce a dansyl group as a fluorophore in the solvent-exposed cap region of the HDAC inhibitor pharmacophore model.

Diagnostic reference levels in pediatric radiology in Austria.

Background: Because of the higher sensitivity to radiation in children, optimization plays an essential role in pediatric radiology. Diagnostic reference levels are a helpful tool to optimize patient dose for standard radiographic procedures.

Methods: A nationwide survey was conducted to determine doses and variation in average dose applied to children for standard X-ray examinations.

A method for the production of composite scintillators for dosimetry in diagnostic radiology.

Plastic scintillators are used in the dosimetry of photons in radiotherapy. Their use in diagnostic radiology is affected by the drop in response at lower photon energies due to inadequate composition (effective atomic number) and chemical quenching. To compensate for this deficiency, a method for the production of composite polystyrene-based plastic scintillators was devised allowing the incorporation of inorganic scintillation powder.

A pilot study exploring the possibility of establishing guidance levels in x-ray directed interventional procedures.

This article summarizes the dosimetric results of an International Atomic Energy Agency coordinated research program to investigate the feasibility of adopting guidance levels for invasive coronary artery procedures. The main study collected clinical data from hospitals located in five countries. A total of 2265 coronary angiograms (CA) and 1844 percutaneous coronary interventions (PCI) were analyzed.

Radioluminescence of some optical fibres.

Measurement of radiation fields with small scintillators as detectors for radiation dose is an attractive method provided that the scintillator luminescence can be discriminated against other unwanted signals. In diagnostic radiology radioluminescence of the optical fibres required for a transmission of the luminescence to an optical detector is the only source for such an impairment of the signal. To find fibres with low radioluminosity a survey of ten commercial fibres including polystyrene (PS), polystyrene wavelength shifting fibres, poly-methylmetacrylate (PMMA) and silica as fibre core material was made.

Bosentan therapy for pulmonary arterial hypertension associated with hereditary haemorrhagic telangiectasia.

Hereditary haemorrhagic telangiectasia (HHT) is a disorder of arteriovenous malformations and telangiectases. In rare cases affected individuals may develop typical pulmonary arterial hypertension (PAH). Vasodilator therapy has not been recommended because of a potential increase in arteriovenous shunt volume.

A fit method for the determination of inherent filtration with diagnostic x-ray units.

A method for the determination of total inherent filtration for clinical x-ray units using attenuation curves was devised. A model for the calculation of x-ray spectra is used to calculate kerma values which are then adjusted to the experimental data in minimizing the sum of the squared relative differences in kerma using a modified simplex fit process. The model considers tube voltage, voltage ripple, anode angle and additional filters.

Bosentan therapy for inoperable chronic thromboembolic pulmonary hypertension.

Background: Bosentan, an oral endothelin (ET)-A/ET-B receptor antagonist, is effective in the treatment of pulmonary arterial hypertension.

Objective: To investigate the safety and efficacy of bosentan therapy in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH).

Design: Case series.

LiF:W as a scintillator for dosimetry in diagnostic radiology.

The use of ionization chambers in diagnostic radiology is not feasible in measurement situations requiring small and robust dose sensors. The composition of LiF:W developed as a scintillator for the measurement of thermal neutrons seems profitable for an application in dosimetry of low-energy photons. Properties of a small LiF:W scintillator were determined with DV- and DH-standard radiation qualities.

Spiral CT and radiation dose.

Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981.

[Dose classification in digital roentgen diagnosis: clinical applications].

Technological improvements in digital radiography and computed tomography have led to a substantial increase of radiation dose that subjectively cannot be detected. In order to reduce dose in a form that may be used in clinical practise, the quality of digital radiograms and computed tomography images should be classified in three classes. Low-dose investigations are indicated in children, in case of therapy control and for imaging organs with high differences in tissue contrast.

Simulation of the effect of anode surface roughness on diagnostic x-ray spectra.

To simulate the effect of the condition of the anode surface on x-ray output the surface roughness of anode fragments of replaced clinical x-ray tubes was determined. A mean roughness of 1.32-5.

Temperature dependence of HU values for various water equivalent phantom materials.

The temperature dependence of water equivalent phantom materials used in radiotherapy and diagnostic imaging has been investigated. Samples of phantom materials based on epoxy resin, polyethylene, a polystyrene-polypropylene mixture and commercially available phantom materials (Solid Water, Gammex RMI and Plastic Water, Nuclear Associates) were scanned at temperatures from 15 to 40 degrees C and HU values determined. At a reference temperature of 20 degrees C materials optimized for CT applications give HU values close to zero while the commercial materials show an offset of 119.

Optimization of the composition of phantom materials for computed tomography.

Using available data for photon attenuation and tissue composition, a computer code was developed for the optimization of the composition of phantom materials for diagnostic radiology. The code allows selection of attenuation data in a photon energy range from 1 to 150 keV and the choice of a suitable weight function in the energy interval chosen. For applications in CT imaging a weight function is available reflecting the contribution of the x-ray spectrum to the CT-signal.

Bone mineral density measurement with dental quantitative CT prior to dental implant placement in cadaver mandibles: pilot study.

Purpose: To correlate torque forces during insertion of screw-type dental implants with bone mineral density (BMD) values determined preoperatively.

Materials And Methods: Dental quantitative computed tomography (CT) was performed with simultaneous imaging of five postmortem mandibles and a calibration standard containing defined concentrations of calcium hydroxyapatite. CT numbers were converted to local BMD values by assuming a linear relationship (BMD = a x HU + b), where a and b are calibration coefficients.

Production of phantom materials using polymer powder sintering under vacuum.

A technique is presented for the production of polymer-based phantom materials from solid polymer powders and various compounds added to adjust x-ray attenuation. After mixing of the finely grained components, the samples are solidified by a sintering process under vacuum. The method described allows a flexible and inexpensive production of phantom materials.

[Quality assurance of mammographic devices].

An account of the technical features of mammographic devices as a consequence of the radiological requirements for imaging the breast is given. For quality assurance of these features specific test procedures have been established which at least since the introduction of the MED-directive 97/43 of CEC have to be applied. A concise summary of these protocols is given.

Local calibrated bone mineral density in the mandible presented using a color coding scheme.

Calibrated information on bone mineral density (BMD) may be used in dental implantology to measure "bone quality". It can be used to estimate the expected primary implant stability preoperatively and to guide the surgeon in selecting optimum implant types and operation techniques. Using a preoperative dental computed tomography (Dental-CT) scan, all of this information can be obtained without additional examinations and thus without additional X-ray exposure of the patient.

[A simple method for estimating effective dose in dental CT. Conversion factors and calculation examples for a clinical low dose protocol].

Purpose: An easily applicable method to estimate effective dose including in its definition the high radiosensitivity of the salivary glands from dental computed tomography is presented. Effective doses were calculated for a markedly dose reduced dental CT protocol as well as for standard settings. Data are compared with effective doses from the literature obtained with other modalities frequently used in dental care.

Helical and conventional CT in the imaging of metallic foreign bodies in the orbit.

Purpose: To compare helical CT to conventional CT imaging in the assessment of orbital metallic foreign bodies with regard to image quality, scanning time, and radiation exposure.

Methods: Twenty-four standardized metallic foreign bodies, placed into the orbit (anterior, epibulbar, posterior) of cadaver heads were studied. Helical CT scanning in the axial plane with multiplanar reconstruction of coronal and sagittal images was performed as well as conventional CT imaging with direct scanning in the axial and the coronal planes (Tomoscan SR 7000, Philips, The Netherlands).

Dry versus conventional laser imagers: film properties and image quality.

The authors compared image quality and stability with a dry laser imager versus a conventional wet laser imager. Hard copies of 56 magnetic resonance imaging and computed tomographic studies were analyzed for gray-scale distribution and temperature stability. Results with the dry laser imager did not reach the quality of results with a wet laser imager, but the performance and ecologic criteria were sufficient to make use of this technique advantageous.

Systematic distortions in magnetic position digitizers.

Medical devices equipped with position sensors enable applications like image guided surgical interventions, reconstruction of three-dimensional 3D ultrasound (US) images, and virtual or augmented reality systems. The acquisition of three-dimensional position data in real time is one of the key technologies in this field. The systematic distortions induced by various metals, surgical tools, and US scan probes in different commercial electromagnetic tracking systems were assessed in the presented work.