VICENTE DE PAULO DE CAMPOS

VICENTE DE PAULO DE CAMPOS

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Performance of TL and OSL techniques using CaSO4 and Al2O3 dosimeters for mean glandular dose (MGD) and entrance surface skin dose (ESD) determination in a digital mammographic unit as alternative dosimeters
2019 - ROCHA, F.D.G.; VILLANI, D.; CAMPOS, V.P.; NOGUEIRA, M.S.; GOULART, M.E.; SICHITO, V.A.; CAMPOS, L.L.
The mammography is the most important and simple tool in the diagnosis of breast diseases in women. In digital mammography, the process of image acquisition, display and storage are separated which allows optimization of each. Despite the innumerous advantages of this technique, such as an accurate diagnosis for women with dense breast, it was noticed an increase of radiation doses to obtain the images by this system. As with any examination that includes x-rays, there is always a small stochastic risk of inducing cancer, it is therefore important to evaluate the risk from the dose delivered to the patient during the screening process. The mean glandular dose within the breast is the recommended quantity to evaluate the risk from radiation to the breast. To guarantee proper conditions of protection for patients, the radiation dose should be as low as reasonably achievable possible and simultaneously compatible with image quality requirements. Thus, this work proposes the use of the thermoluminescent (TL) CaSO4:Dy sintered discs, produced at IPEN, widely used in individual, environmental and area monitoring in Brazil, and Al2O3:C optically stimulated luminescence (OSL) ‘dot’ dosimeters, manufactured by Landauer® Inc., as application as easy-to-use and low cost alternative dosimeters to evaluate the entrance skin doses (ESD) delivered to patients, the half value layer (HVL) and the mean glandular doses (MGD) in a mammographic digital unit, comparing these two techniques with the results obtained using an Allin- one QC meter. The results obtained demonstrated that the TL and OSL dosimetry systems and the CaSO4 and Al2O3 dosimeters used are able to evaluate the entrance skin dose as well as mean glandular doses in a digital mammographic unit accurately within the requirements, and they can be considered a practical, simple, easy-touse and low cost tools for verification of these items in a Quality Assurance Program.
Leaked filters for energetic an angular dependence corrections of thermoluminescent response
2007 - MANZOLI, JOSE E.; CAMPOS, VICENTE de P. de; SHAMMAS, GABRIEL I.J.
Selecionamento de detectores de radiacao segundo sua sensibilidade e viabilidade para dosimetria termoluminescente
2003 - MANZOLI, J.E.; CAMPOS, V.P.
Assessment of CaSOsub(4):Dy thermoluminescent detectors response for different phantom materials and proton energies
2011 - ROCHA, FELICIA DEL G.; CAMPOS, VICENTE de P. de; CAMPOS, LETICIA L.
Determination of radiation direction in environmental monitoring
2009 - CAMPOS, VICENTE de P. de; MOURA, EDUARDO S.; ROCHA, FELICIA D.G.; MANZOLI, JOSE E.
The assessment of environmental exposure has been performed in Brazil using the thermoluminescence technique at Thermoluminescence Dosimetry Laboratory (LDT), at Nuclear and Energetic Research Institute (IPEN/CNEN-SP). To carry out these measurements, several thermoluminscent dosimeters (TLD's) were used to measure the expose. In this procedure, very few information of direction where the radiation came from is available. A vague supposition about the direction from where the radiation came from could be inferred only by evaluation of multiple dosimeters displaced at entire region of monitoring, but this demand to much effort or sometimes become impractical for certain situations. In this work, a single device is used to provide information about the direction from where the radiation came through. This device is called directional dosimeter (DD)[1]. Using more than one DD it is possible to reduce the uncertainty of the measurements and determine the radiation source position. The DD basically consists of a regular solid with high effective atomic number, where one TLD is positioned at each face. The DD allows evaluating the environmental exposure and the direction of the radiation by a simple vector sum. At each face of the DD, it is associated an orthogonal vector, and modulus of this vector represents the correspond exposure measured by the TLD. The direction of the radiation source is the sum of these faces vectors. The prototype used in this work was a lead cube with six TLDs of CaSO4:Dy/Teflon. The TLDs have high sensibility and are already used in area, environmental and personal monitoring. The measurements had shown the correct environmental exposure and a good indication of the radiation direction.
Assessment of the ambiental exposure at IPEN using CASOsub(4):Dy detectors with different filters combination
2007 - CAMPOS, VICENTE de P. de; ROCHA, FELICIA D.G.; RODRIGUES, LETICIA L.C.
Evaluation of reproductibility and detection limit of CaSOsub(4):Dy radiation detectorsemission spectrometry after wet partial digestion and neutron activation analysis
2006 - MANZOLI, JOSE E.; CAMPOS, VICENTE de P. de; DOI, MIRIAN S.
Measurement response of thermoluminescent dosimeter, TLD, used by workers or placed at positions where gamma radiation field could be in action affecting biological tissues, should be completely characterized, in order to achieve the radiation quantity with precision and confidence. Among the evaluations concerned to its characterization, the detector reproductibility is of fundamental importance, because detectors present inside the TLD will be used many times in routine. Reproductibility is studied by repeated exposure to the same radiation field. The minimum detection limit is another important characteristics of a TLD. In this work evaluations of reproductibility and minimum detection are presented, for dosimeters produced at IPEN.