Radiosurgery dosimetry using CaSO4:Eu OSLD film-a feasibility study.

Recent studies demonstrated that optically stimulated luminescence (OSL) systems allow the evaluation of doses for 2D mapping in a relatively fast and simple way and results show submillimeter resolution. This work presents, for the first time, an optically stimulated luminescence dosemeter (OSLD) in the form of film made with CaSO4:Eu particles embedded in a silicone elastomer matrix. The OSLD film was produced using a low-cost and relatively simple methodology. This film is reusable and the signal can be satisfactorily bleached using blue LEDs. The main dosimetric properties were evaluated using TL/OSL Risø reader with blue stimulation and Hoya U-340 filter. Investigation shows repeatability within 3% when measuring with the same film sample. Regarding the OSLD film homogeneity, nearly 12% sensitivity change was observed within the 5 × 5 cm2 produced film. Additionally, the dose response curve shows linearity from 5 to 25 Gy. Fading of the OSL signal is relatively high, about 50% in the first week and then is stable. Nevertheless, a 3 × 3 cm2 OSLD film was successfully used to map dose distribution in radiosurgery (6 MV photon beam). This work demonstrates the feasibility of 2D dosimetry using reusable OSLD films based on CaSO4:Eu.

Using the optically stimulated luminescence technique for one- and two-dimensional dose mapping: a brief review.

In respect of radiation dosimetry, several applications require dose distribution verification rather than absolute dosimetry. Most protocols use radiological and radiochromic films and ionization chambers or diode arrays for dose mapping. The films are disposable which causes the precision of the results dependent on film production variability. The measurements with arrays of ionization chambers or diodes mainly lack spatial resolution. This review aims to provide an overview of the use of optically stimulated luminescence detectors (OSLDs) for one-dimensional (1D) and two-dimensional (2D) dose mapping in different applications. It reviews the ideas, OSL materials, and applications related to the assessment of dose distribution using OSLDs in the form of film or ceramic plate (BeO). Additionally, it reviews research published in the international scientific literature from 1998 to 2021. As an outcome, a table containing the main characteristics of each relevant paper is shown. The results section was divided by the type of OSL material, and we briefly described the principal findings and the significant developments of each mentioned study such as film production and OSL reader assembly. The purpose of this study was to present an overview of the main findings of several research groups on the use of OSLD in the form of film or plate for 1D and 2D dose mapping. Finally, the potential future development of dose mapping using OSLD films was outlined.

TL and OSL dose response of LiF:Mg,Ti and Al2O3:C dosimeters using a PMMA phantom for IMRT technique quality assurance.

The principle of IMRT is to treat a patient from a number of different directions (or continuous arcs) with beams of nonuniform fluences, which have been optimized to deliver a high dose to the target volume and an acceptably low dose to the surrounding normal structures (Khan, 2010). This study intends to provide information to the physicist regarding the application of different dosimeters type, phantoms and analysis technique for Intensity Modulated Radiation Therapy (IMRT) dose distributions evaluation. The measures were performed using dosimeters of LiF:Mg,Ti and Al2O3:C evaluated by techniques of thermoluminescent (TL) and Optically Stimulated Luminescence (OSL). A polymethylmethacrylate (PMMA) phantom with five cavities, two principal target volumes considered like tumours to be treated and other three cavities to measure the scattered radiation dose was developed to carried out the measures.

Dosimetric study of thermoluminescent detectors in clinical photon beams using liquid water and PMMA phantoms.

The purpose of this study was the dosimetric evaluation of thermoluminescent detectors of calcium sulphate doped with dysprosium (CaSO4:Dy) produced by IPEN compared to the TL response of lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti) dosimeters and microdosimeters produced by Harshaw Chemical Company to clinical photon beams dosimetry (6 and 15 MV) using liquid water and PMMA phantoms.

Estudo da dosimetria termoluminescente fototransferida no CaSo4: Dy utilizando radiaçäo de laser / Study of phototransfer thermoluminescent dosimetry in CaSO4: Dy using laser radiation

O objetivo deste trabalho é estudar a Termoluminescência Fototransferida (PTTL) no CaSO4: Dy utilizando as radiações de laser e ultravioleta (UV). O CaSO4: Dy é um material termoluminescente (TL) extremamente sensível que tem um peco pico dosimétrico situado a temperatura de 220 graus Celsius e é utilizado com sucesso na dosimetria da radiação gama.

Resultados estatísticos da monitorizaçäo individual externa em setores da área médica no ano de 1995 / Statistics results of external individual monitoring in sectors of medical area in 1995

Este trabalho analisa os resultados da monitoração individual externa de trabalhadores da área médica enfocando os níveis de dose em diferentes departamentos de diferentes hospitais.

Medidas dos fatores de conversäo H*(d)/Ka pra feixes de raios-X diagnóstico / Measure of H*(d)Ka conversion for Diagnostic X-rays fields

Este trabalho apresenta os resultados da determinação experimental dos coeficientes de conversão da grandeza de calibração kerma no ar para a nova grandeza da ICRU de monitoração de área, H*(d). As medidas foram realizadas nas profundidades 10, 50 e 60 mm de uma esfera de PMMA de 30 cm de diâmetro em feixes de raios-X de radiodiagnóstico.