New dosimetric approach for multidimensional dose evaluation in gamma knife radiosurgery. Technical note.

During the past two decades, the progress in computerized treatment planning systems has led to more accurate imaging and therapy by using the gamma knife, especially with the smallest collimators (4 mm). However, the ionization chambers that have been used to calibrate the gamma knife are not useful with the smallest collimators because the chambers are too big compared with the irradiated volume. Therefore, it is important to develop more suitable dosimeters. This study proposes a new dosimeter method. The FriXyGel method proposed here is based on a phantom dosimeter, an acquisition chain, and dedicated software. This dosimeter uses an agarose gel into which a ferrous sulphate solution (Fricke solution) and a metal ion indicator (xylenol orange) are incorporated. The absorbed dose is detected through measurements of visible light transmission, imaged by means of a charge-coupled device camera provided with a suitable optical filter. Gel layers are imaged before and after irradiation, and the differences in light absorption are related to the absorbed dose. By choosing convenient thickness of gel layers and by building up a phantom with different gel slices, it is possible to obtain a three-dimensional (3D) representation of the absorbed dose. The final 3D representation is reached after several mathematical processes have been applied to the images. The first step identifies and reduces all factors that could alter the original data, such as nonuniformity in illumination. Then, after calibration procedures, it is possible to obtain absorbed dose values and to discover their 3D representation. This goal has been reached by developing appropriate software that performs all the calculations necessary for spatial representation routines and prompt comparison with theoretical calculations.

[Acute phase proteins as markers of septic risk in surgical patients]. / Le proteine di fase acuta (APP) quali markers di rischio settico nel paziente chirurgico.

A heterogeneous group of surgery patients at septic risk was studied through monitoring of acute phase proteins (APP). Plasma levels of 8 acute phase proteins (C-reactive, alpha-1 antitrypsin, fibrinogen, ceruloplasmin, transferrin, albumin, prealbumin, alpha-2 macroglobulin) were measured in the pre- and postoperative period of septic surgery patients suffering from disease processes in various sites and with different aetiopathogenesis. The experiment is related to some interesting research proposed by authors in the Shock Physiopathology Study Centre of the Catholic University of Rome and their results. The constant finding of increased values of PCR, fibrin, cerul, alpha-1 Tryp in the septic risk surgery patient and their normalisation following treatment is particularly significant. In these same cases, a depression or, depending on circumstances, normal findings of Transf, alpha-2 Macro, Albu and Prealbu were observed. The results point to the practical utility an high reliability of APP changes as markers of septic risk.

[Cancer of the stomach, the choice of surgery based on correct staging: total or subtotal gastrectomy?]. / Il cancro dello stomaco, da una corretta stadiazione la scelta dell'intervento: gastrectomia totale o gastrectomia subtotale?

On the basis of the literature and of personal experience, the problem of the extent of demolition time, total gastrectomy or subtotal gastrectomy for patients suffering from stomach cancer is analysed. It is considered that total gastrectomy does not always lead to longer survival by comparison with subtotal gastrectomy and that in certain cases the latter, after careful consideration of a series of variables, may be the operation of choice.

[Acute unrestrainable digestive hemorrhage caused by primary neurogenic tumor of the duodenum]. / Emorragia acuta digestiva irrefrenabile da tumore neurogeno primitivo del duodeno.

An extremely rare case of primary benign neurogenic tumour of the duodenum that determined a picture of severe digestive haemorrhage is reported.