[Radiation exposure of the embryo and the fetus: real risks or unjustified fears?]. / Esposizione alle radiazioni dell'embrione e del feto: rischi reali o ingiustificati timori?

The authors discuss the problem of radiation damage to the individual developing in utero, and summarize the information available in the literature on the subject. Additional risks induced by ionizing radiations are classified with reference to gestational age and dose absorbed by the fetus. Such risks concern the possibility of mental retardation from the 8th to the 15th gestational week, and of developing a malignant disease from the 3rd to the 15th gestational week. We report the dose values received by the fetus as a result of both radiodiagnostic examinations and the Chernobyl nuclear accident: the doses were generally very low, which leads us to the conclusion that additional risks are of the same order of magnitude as the fluctuations in the natural congenital malformations. Thus, prenatal irradiation for diagnostic examinations does not generally represent a reason to recommend therapeutic abortion. However, it is always important to carry out a careful evaluation of the dose absorbed by the fetus and to correctly inform the mother about eventual radiation-induced risks.

[Role and possibilities of compensation filters in lateral decubitus radiographs in opaque enemas]. / Ruolo e possibilità del filtro di compensazione nelle proiezioni in decubito laterale del clisma opaco.

A wedge-shaped plexiglass compensation filter for use in lateral decubitus radiographs of double contrast barium enema examinations has been designed. This filter, which has been used since February 1985, was compared with a second plexiglass filter, made by E-Z-EM. Voltage and amperage were kept contrast. Two different experiments were conducted in order to demonstrate the benefits of routine use of this compensation filter. First, the changes in skin dose were assessed using an ionization chamber on a phantom. Secondly, three radiologists examined a series of 80 consecutive barium enemas without knowing which had been performed using the new filter. Out of the 70 examinations they considered excellent, as many as 45 had been performed with the new filter. Personal experience and the studies described show that the use of a compensation filter improves the accuracy and thus the diagnostic quality of the examinations as it enhances the detail of the anatomic structure of the colon; moreover the filter reduces skin exposure by up to 73.1% (EZ-E-EM filter 47.3%) and, at the same time, less radiographic films are needed. Routine use of a plexiglass compensation filter in lateral decubitus radiographs while performing a double contrast barium enema examination, is strongly recommended especially in obese patients.

Left ventricular diastolic filling rate assessed by gated radionuclide angiography in patients with coronary artery disease.

This study was undertaken to determine the significance of diastolic left ventricular function in 26 normal subjects and in 74 patients with coronary artery disease (CAD). Gated radionuclide left ventriculography in supine position and left anterior oblique projection was performed at rest in both groups considered and during exercise in 11 normal subjects and in 35 patients with CAD. Compared with the normal subjects, the group of patients with CAD showed lower values of global and regional ejection fraction as well as of peak ejection and filling rates. 33 patients with CAD, presenting an ejection fraction greater than 54%, showed similar values of global and regional ejection fraction, compared with the group of normal subjects, while peak filling rate was significantly lower. During exercise peak filling rate significantly increased in normal subjects and in patients with CAD; this increase was constant and similar in the various subgroups considered among patients with CAD. We conclude that peak filling rate represents a more sensitive index than ejection fraction in evaluating left ventricular function in patients with CAD, as shown by the comparison between normal subjects and patients with CAD, who had an ejection fraction greater than 54%.