Study of suitability of Fricke-gel-layer dosimeters for in-air measurements to characterise epithermal/thermal neutron beams for NCT.

The reliability of Fricke gel dosimeters in form of layers for measurements aimed at the characterization of epithermal neutron beams has been studied. By means of dosimeters of different isotopic composition (standard, containing (10)B or prepared with heavy water) placed against the collimator exit, the spatial distribution of gamma and fast neutron doses and of thermal neutron fluence are attained. In order to investigate the accuracy of the results obtained with in-air measurements, suitable MC simulations have been developed and experimental measurements have been performed utilizing Fricke gel dosimeters, thermoluminescence detectors and activation foils. The studies were related to the epithermal beam designed for BNCT irradiations at the research reactor LVR-15 (Rez). The results of calculation and measurements have revealed good consistency of gamma dose and fast neutron 2D distributions obtained with gel dosimeters in form of layers. In contrast, noticeable modification of thermal neutron fluence is caused by the neutron moderation produced by the dosimeter material. Fricke gel dosimeters in thin cylinders, with diameter not greater than 3mm, have proved to give good results for thermal neutron profiling. For greater accuracy of all results, a better knowledge of the dependence of gel dosimeter sensitivity on radiation LET is needed.

Medicines for children licensed by the European Agency for the Evaluation of Medicinal Products.

OBJECTIVE: . The aim of this study was to evaluate the number and the characteristics of medicines approved for children in Europe by the European Agency for the Evaluation of Medicinal Products (EMEA) and whether the paediatric studies supporting the authorisation were in accordance with the Note for Guidance on the Clinical Investigation of Medicinal Products in children (CPMP/ICH/2711/99). We also considered any possible difference between the EMEA and the Food and Drug Administration (FDA) paediatric medicines evaluations. METHODS: . We examined the drugs authorised by the EMEA through the centralised procedure from January 1995 to September 2001 deriving information from the "European Medicines - Database" (EMD) set up in 1998 by the Italian Group for Pharmacoeconomic Studies (GISF) and sponsored by the Italian Ministry of Health. The analysis of paediatric data has been managed by experts belonging to the Clinical Pharmacology Working Group of the Italian Paediatric Society. The following parameters were assessed: active substance, year of approval, anatomical therapeutic and chemical (ATC) code, therapeutic indications, age for which the drug is authorised, interest to children and paediatric studies supporting a paediatric authorisation. European Public Assessment Reports (EPARs) were considered as reference sources. RESULTS: . The median percentage of drugs authorised for children from 1995 to 2001 (September) is 35% of the total of commercially available drugs; only 16 medicines have been approved for children under 2 years of age (11%), ten of these being vaccines. Medicines for children shared out 9 ATC classes, 24 belonging to the J- (anti-infective agents) -ATC class. Thirty-nine medicines were authorised on the basis of at least one clinical trial (27 phase III, 6 phase II, 6 phase I) while eight active substances have been licensed without any paediatric investigation. CONCLUSIONS: . Under the EMEA centralised procedure, several active substances have been licensed for children. Consequently serious and life-threatening diseases as AIDS and diabetes are now treatable, in a legal framework overcoming the orphan status of the past years. Despite the reported encouraging results, the number of drugs devoted to children remain low and important ATC classes, as L-(oncology) or N-(neurology), are still 'orphans' of innovative medicines. At the same time few medicinal products are specifically studied in children. Consequently, more efforts have to be made to increase the number of drugs assessed and licensed for the paediatric population, and manufacturers should be required to supply data on the effects of new drugs in children when the products are expected to offer a benefit over existing therapies.