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Biomedical subjects

G Pedroli

Publications and source records attributed to G Pedroli.

15 recordsLinked to original sources

[Digital radiography with phosphorus memory: verification of the centering of the patient in high-energy radiotherapy].

A digital radiographic system using storage phosphor detectors was employed in order to verify radiotherapy treatments with high energy photon beams (60Co-18 MV X-rays). The wide range linearity of the detectors and also the possibility of digital image post-processing allowed portal films to be obtained with sufficient contrast in all treatment techniques, particularly in the case of mantle fields. The use of digital radiography may become an easy and valuable procedure for therapy verification.

Algorithms

Dose distribution of 123I in the thyroid gland and its maximum permissible concentrations.

The calculation of the dose distribution in the thyroid tissues and of the maximum permissible concentrations in the air and in drinking water was carried out for 123I. In fact because of the recent use of this radionuclide in radioisotopic diagnostics the dose to both the patients' and operators' thyroids due to 123I must to be known. In order to obtain a correct estimate it is necessary, however, to consider the distribution of the radionuclide in the thyroid tissue and the changes in this distribution depending on the dimensions of the follicles. Taking into account the dose at the follicular cell-colloid interface, the maximum permissible concentrations in the air and in drinking water were calculated as being 6 x 10-8 muCi/cm3 and 4 x 10-4 muCi/cm3 respectively.

Air Pollutants, Radioactive

[Digital radiography in urography].

The clinical utility was evaluated of a computed radiographic system in urography. The system (FCR 101, Philips Medical Systems, Inc., Shelton, CT) is based on a photo-stimulatable phosphor screen (imaging plate) for X-ray image detection and storage. The X-ray information recorded on the imaging plate is converted into digital from and processed by means of a computer. After processing is completed, the digitized image is reversed back to analogic signals, which modulate the intensity of a laser beam scanning the image on a single-emulsion film (Fuji CR 633). Two hundred IVP's were obtained in four groups, of 50 patients each, with normal azotemic values by rapid infusion of a low osmolality contrast medium (iopamidol 150 mgI/ml). While conventional radiographs were performed on the first group of patients with the injection of 0.6 gI/kg body weight of contrast medium, digital examinations were carried out, in the remaining three groups, with the injection of 0.6, 0.3 and 0.12 gI/kg, respectively. The digital images were processed with the "Abdomen-routine" program. A specific algorithm was implemented in order to reduce the excessive contrast resolution of the bladder, which is due to the characteristics of the nonionic contrast medium and enhanced by the reading program. The image details were evaluated by two observers and then statistically analyzed with nonparametric tests. Statistical analysis did not show any difference in the quality of digital and screen-film images. Image processing improved some inadequate images, by reducing the contrast resolution of the bladder, and allowed a better detection of some details. Low doses (0.3 gI/kg) of a low osmolality (150 mgI/kg) contrast medium were enough to obtain good images. Another biological advantage was obtained by a consistent radiation dose reduction (about 40%).

Adolescent