Low dose CT of the heart: a quantum leap into a new era of cardiovascular imaging.

In 10 years, computed tomography coronary angiography (CTCA) has shifted from an investigational tool to clinical reality. Even though CT technologies are very advanced and widely available, a large body of evidence supporting the clinical role of CTCA is missing. The reason is that the speed of technological development has outpaced the ability of the scientific community to demonstrate the clinical utility of the technique. In addition, with each new CT generation, there is a further broadening of actual and potential applications. In this review we examine the state of the art on CTCA. In particular, we focus on issues concerning technological development, radiation dose, implementation, training and organisation.

EXPERIMENTAL VALIDATION OF ALGORITHMS USED TO ESTIMATE EFFECTIVE DOSE DURING INTERVENTIONAL RADIOLOGY PROCEDURES.

In IR procedures, in order to evaluate the effective dose, the importance of the double dosemeter has been recognised, one worn above and one under the apron. Over the last few decades several algorithms have been developed to combine the readings of the dosemeters, however currently there is no international consensus on which is the best one. In this work, eight irradiations, corresponding to typical interventional radiology procedures, were carried out in order to experimentally verify the accuracy of the algorithms. The patient was substituted by solid water-equivalent (RW3) layers, while effective dose to personnel was calculated by TLDs inside the Alderson Rando phantom. The results show that most of the algorithms, with a few exceptions, are too conservative, however there are many factors which can affect their accuracy, so it is impossible to achieve a high level of precision in the evaluation of the effective dose.

[Risks from magnetic fields and radiowaves in equipment for magnetic resonance tomography]. / Rischi da campi magnetici e da radioonde in apparecchiature per tomografia a risonanza magnetica.

The use of Nuclear Magnetic Resonance Imaging for diagnostic purposes requires a careful analysis of potential risks for workers, patients and public. Aim of this work is a review of the most important biological effects produced by static magnetic fields, radiofrequency fields and field gradients. It's common opinion in fact that the use of magnetic and radiofrequency fields instead of ionizing radiations fields is a safety warranty for patients and workers. Biological experiments in small animals and microorganisms show that also in this case some risks may be expected, due to the trend to employ as much high as possible magnetic fields (and therefore radiofrequency fields). The available data show that the normally used magnetic and radiofrequency fields are below the threshold for somatic effects but denote the necessity of a careful risks/benefit analysis for some patients groups (pacemakers and small surgical metallic implants carriers) and the need of extended and deep studies to specify a possible synergy of different physical agents and incidental oncogenic and teratogenic consequence on the patient.

[The evaluation of the performance of a new-concept screen-film system]. / Valutazione delle prestazioni di un sistema schermo pellicola di nuova concezione.

Aim of this work is to show the results of the evaluation of the sensitometric properties of a new Du Pont anti cross-over radiographic film system called Ultra Vision, based on a new film and different YTaO4 undoped screens whose emission is centered at about 335 nm. Fog, contrast, latitude, sensitivity, noise and resolution were tested: the MTFs were obtained by exposing a standard resolution pattern and using the "zero"-frequency step as a knife edge. The image of this knife edge was scanned with a microdensitometer with a 20 microns slit. The results (at 70 kVp with 2.5 mm Al and 2.5 mm Cu total filtration), compared with those of Du Pont conventional radiographic screen-film systems Cronex 10 S/Quanta, show that the new system significantly increases contrast, sensitivity and resolution and will consequently improve, in the clinical use, radiographic image quality.

[Chernobyl accident: dosimetric evaluation and estimation of risks]. / Incidente di Chernobyl. Valutazioni dosimetriche e stime dei rischi.

The results of dosimetric evaluations carried out after Chernobyl accident in the Health Physics Department of Niguarda Ca' Granda Hospital (Milan) on air, rain and ground contamination are presented. The results obtained show that the incidence of stochastic late effects, both somatic and genetic, will be so low that practically will not be distinguishable from "natural" incidence.