Recent epidemiological studies suggested to lower the threshold dose for radiation induced cataract in the eye lens. Therefore, eye lens radiation protection became to play a more important role in personal dosimetry. The main objective of this work is to propose a new methodology for prototyping and benchmarking of an eye lens dosimter based on the equivalent dose to the sensitive part of the eye lens, using CAD Software and Geant4 Monte Carlo simulations with mesh modelling and 3D printing. A 3D printed dosemeter was type tested based on IEC 62387:2012, in terms of energy and angular dependence for the measurements of Hp(3). The results show that the methodology employed is suitable for the development of new eye lens dosemeters.

This work demonstrates the use of high-resolution 3D printing to fine-tune the low energy dependence of an eye lens dosimeter holder associated to a BeO OSL detector element (ezClip). Five geometries of the denominated iBe dosimeter were developed, three with a variation in the thickness of the wall in front of the sensitive element that tailor the response at low radiation energies; and three with variations of width and curvature in order to vary the angular response of the dosimeter badges. Additive manufacturing was accomplished using stereolithography which gave a high degree of accuracy and precision. The optimised dosimeter badges showed a low energy and angular dependence, within −20% to +20% in the energy range of 24 keV to 662 keV and from 0 to 60° incidence; and within −10% to +10% in the energy range of 24 keV to 164 keV and from 0 to 60° incidence. In contrast to other dosimeters with higher effective atomic numbers, the use of BeO as the sensitive element resulted in a flat energy and angular dependence response at low energies. A significant reduction in the measurement uncertainty in the diagnostic radiology energy range was achieved.

The stereotactic radiosurgery (SRS) is a technique that uses multiple beams extremely collimated of ionizingradiation to treat intracranial lesions and functional abnormalities, with high geometric precision and dosimetricaccuracy. The use of small fields is already a reality in modern radiotherapy techniques. However, the accuracyin small-field dosimetry is challenging because of several process physics and aspects related to the detector. Theaim of this paper is to evaluate the response of a dosimetric system developed by Nuclear Energy Department ofFederal University of Pernambuco (DEN/UFPE) for small field dosimetry. Measurements of, output factor (OF),off-axis ratio (OAR) and percentage depth dose (PDP) were performed with this dosimetric system andcompared with the results obtained with a commercial diode and treatment planning system data. The resultsshowed that the Diode-DEN presents a reliable and economical alternative for small fields dosimetry used intreatments of SRS. This detector can be used for validation of dates obtained in commissioning of linearaccelerator and inserted in Treatment Planning Systems (TPS).

Stereotactic Radiosurgery (SRS) is a procedure that uses ionizing radiation in a single fraction or few fractions to treat intracranial lesions. Usually, for these treatments, small photon fields, formed by circular collimators or micro multileaf collimators are used. The objective of the present work is to compare the measurements of the dose in depth (PDD), the off-axis ratio (OAR), and the output factor (OF) using Edge diode and radiochromic films and analyzing the agreement between the two detectors during these measures. In the gamma index analysis of the profiles, the minimum percentage reached was 98.3% of the points in the criterion 1% and 0.5 mm. The maximum percentage difference in the output factor was 2.79% for a cone 4 mm and 10FFF. In the gamma index analysis of the PDDs, the minimum percentage reached was 97% of the points in the criterion 1% and 1mm. The results show a good agreement between the edge detector and the film in small field measurements for radiosurgery.

Topaz [Al2SiO4(OH,F)2] is usually found in nature and can presents different colours. The aim of this paper is to evaluate the thermoluminescence (TL) and the optically stimulated luminescence (OSL) response of five types of topaz collected from three different Brazilian states. The topaz samples studied have a yellow, blue and colourless coloration. The TL results showed that colourless samples from the state of Rio Grande do Norte present a TL glow curve with a main peak at ~260ºC. The others colourless topaz from Teofilo Otoni e Mato Grosso do Sul, besides the peak of ~260ºC, the present another peak at 160 ºC. The highest TL intensity was observed with the colourless topaz from RN. A linear TL dose curve response was also observed with these samples from the gamma radiation of 60Co in the range of 0.01 Gy to 3.5 Gy. The blue light stimulation (BSL) showed almost the same intensity response for the three colourless topaz samples. None topaz sample showed response to optical infrared stimulation (IRSL).