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A Torresin

Publications and source records attributed to A Torresin.

24 records · Page 2Linked to original sources
PubMedDate not supplied

Image quality and dose in computerized tomography: evaluation of four CT scanners.

Spatial resolution, statistical noise, and patient dose are important parameters for the evaluation of the performances of computerized tomography (CT) scanners. These parameters are combined to develop some "synthetic indices," and to be able to describe intrinsic properties of a CT scanner (the maximum obtainable spatial resolution and dose efficiency). This type of analysis has been applied to the evaluation of four CT scanners, three of third, and one of fourth generation.

Radiation Dosage↗
PubMedDate not supplied

Neutron measurements around medical electron accelerators by active and passive detection techniques.

Passive and active detection techniques have been employed in order to measure neutron fluence rates and corresponding exposure rates around medical electron accelerators operating at energies well above the neutron binding energies of the structural materials. In these conditions from the treatment head, in the direct photon flux and from the shielded region, a fast neutron flux emerges which is partly absorbed and partly scattered by the walls, eventually establishing a nearly uniform thermal and epithermal flux in the room. Both direct and scattered flux contribute to the dose to the patient. A smaller neutron dose rate can also be found outside the treatment room, where the therapy staff works. Passive detectors, of moderation type, have been employed in the treatment room and 3He active detectors in the external zones. For the treatment room the activation data were compared with results of Monte Carlo simulation of the neutron transport in the room. Technical features of the two measures are briefly presented and results obtained around three different types of accelerators are reported. At the higher beam energies, i.e., 25 MV, a neutron dose of 0.36 Sv was estimated in the treatment field in addition to a therapeutic x-ray dose of 50 Gy. At lower energies or out of the treatment field the neutron dose drops significantly. In the external zones the dose rates everywhere are below the recommended limits and normally very low, the highest values being recorded in positions very close to the access door of the treatment room.

Humans↗
PubMedDate not supplied

[Rhodococcus equi infections in AIDS: personal cases].

We report on the occurrence of an uncommon pathogen, Rhodococcus equi (R.e.) in HIV infection. In the period february 1990-July 1991 we performed the diagnosis of R.e. infection (lung, lung-central nervous system) in two infected patients, aged 27 and 31 years, both males, drug addicts, classified as CDC IV. In the first of them an cavitating right bronchopneumonia (bpm) was diagnosed as of tuberculous origin, on the ground of the microscopic demonstration of an acid-fast, gram-positive strain in b.a.l.. A standard antituberculous regimen was uneffective and R.e. was eventually isolated in three blood culture taken shortly before the exitus and at post-mortem examination of the lungs. In the second patient a subclavian right bpm developed without microbiological evidence of any common pathogen. A third-generation cephalosporin course was only partially successful (clinical amelioration, incomplete clearing of radiological findings). After 3 months the patient relapsed and an aseptic meningitis developed. Cultures of blood and csf yielded a R.e. strain; post-mortem examination revealed a diffuse, cavitating bpm. Our personal experience underlines the difficulty in recognizing R.e. infections in compromised host, because of similarity to other entities (i.e. tuberculosis) and the absence of pathognomonic hints.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

[A proposed method for the automatic interpretation of images obtained by computer tomography].

A preliminary study is described relative to the possibility of using methods of automatic image interpretation in the field of biomedical images. These general methods are capable of recognizing characteristic shapes inside the image. In this paper the structures are described and interpreted. These methods are capable of outlining shapes which are important from a clinical point of view--e.g., spine, vertebrae. They can also evaluate the shapes by plausible methods, to explain the meaning of the whole image. A feasibility study is described concerning the automatic recognition of vertebral contour in axial CT images. The results suggest that the employed techniques can be used in real diagnostic applications.

Feasibility Studies↗
PubMedDate not supplied

[Proposal of a method of automatic interpretation of images in x-ray computed tomography].

A preliminary study is described relative to the possibility of using methods of automatic image interpretation in the field of biomedical images. These general methods are capable of recognizing characteristic shapes inside the image. In this paper, the structures are described and interpreted. These methods are capable of outlining shapes which are important from a clinical point of view--e.g., spine, vertebrae. They can also evaluate the shapes by plausible methods, to explain the meaning of the whole image. A feasibility study is described concerning the automatic recognition of vertebral contour in axial CT images. The results suggest that the employed techniques can be used in real diagnostic applications.

Feasibility Studies↗