[Single-slice and multi-slice computerized tomography: dosimetric comparison with diagnostic reference dose levels]. / Tomografia computerizzata a strato singolo e a strato multiplo: confronto dosimetrico con i livelli diagnostici di riferimento.

PURPOSE: The absorbed dose during clinical examinations of the head, thorax, abdomen and pelvis performed with a single-slice CT scanner and a new multi-slice CT system was measured and compared. Technical parameters, defined at installation and memorized on the two CT machines relate to a standard-sized patient and were considered the reference standard. Our experimental data were also been compared with the Diagnostic Reference Levels (D.L. 26/5/2000 n.187, Annex V). MATERIAL AND METHODS: We compared the performance of a multi-slice GE LightSpeed QX/i ADVANTAGE to that of a single-slice GE ProSpeed SX. The radiation beam profiles were measured at isocenter using a phosphor plate. Dose measurements were performed, according to the EUR 16262 EN Guidelines, with a 10-cm long CT pencil ionisation chamber and two PMMA phantoms (CEI EN 61223-2-6) for head and body respectively. RESULTS: The obtained (normalised and weighted) computed tomographic dose index (nCTDIW) values were systematically higher for the multi-slice system (up to 36%) and the dose-length product (DLP) values on the multi-slice scanner exceeded the equivalent single-slice DLP values. The values were, however, always lower than DRLs, except in the case of the head multi-slice protocol, the technical parameters of which need to be improved. Our results allowed moreover to calibrate the automatic dose evaluation system of the multi-slice system, which systematically underestimated DLP values. DISCUSSION AND CONCLUSIONS: The comparison showed that the multi-slice scanner delivers a higher dose compared to the single-slice scanner. This is due to the radiation beam profile which is wider than the total active detector width, to the shorter focal spot-to-isocenter distance and to the effective scan length, which is longer than the nominal irradiated volume because the reconstruction algorithm of a multi-slice helical CT image requires the projection data from all detector rows. Nevertheless, the technology of new CT systems equipped with a multiple row detectors array can improve the protection of the patient thanks to very short irradiation time (less than 1 s) and reduced current values. In order to optimize the dose to the patient some acquisition parameters have been adjusted for head examinations.

153Sm-EDTMP radionuclide treatment of bony metastatic disease: a radiation protection evaluation.

The aims of the study were the identification and optimization of the radiation protection measures for in-patients who underwent palliative radionuclide therapy for bone metastases with 153Sm-EDTMP activities lower than 3 GBq. The suitability of the preventive procedures from the contamination of places and objects, and for the protection of the hospital staff, other patients and relatives from the danger of external radiation and internal contamination has been evaluated by carrying out a series of measurements both of superficial contamination inside the confinement room and of the dose near the treated patients. The results show that the contamination of the places and the objects close to treated patients is really low. The greatest risk of contamination depended on the management of the physiological waste that, therefore, should be collected and disposed as radioactive one. The measurements of external radiation show that nearby the confinement room the dose limit for public is not exceeded. The same is true for the dose limit of 3 mSv established for relatives who, when taking care treated patients, receive a dose lower than 20 microSv a patient. The fulfillment of the proposed radiation protection measures assures the containment of the risk of exposure and contamination for nursing and medical staff involved in radionuclide-based therapy.

[Evaluation of neuropsychological parameters in a group of metal mechanics occupationally exposed to radio frequencies]. / Valutazione di alcuni parametri neuropsicologici in un gruppo di lavoratori metalmeccanici professionalmente esposti a radiofrequenze.

In view of the increasing interest in electromagnetic fields, the effects on behaviour were studied in a group of foundry workers following prolonged exposure to radiofrequencies. The results of behavioural tests revealed significant differences between the exposed and control groups as regards neuropsychological performance. Anxiety and depression tests, however, indicated no pathological alterations, in contrast to previous observations. Nevertheless, the results need to be confirmed by further, more detailed studies.