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Velasques De Oliveira S.M.,Institute Radioprotecao e Dosimetria IRD CNEN | Carlos M.T.,Institute Radioprotecao e Dosimetria IRD CNEN | Carneiro M.P.,Multi Imagem PET CT | Da Silva J.W.E.,Multi Imagem PET CT | And 5 more authors.
Cellular and Molecular Biology

The aim of the present work is to propose a protocol for quantification of 18F-FDG activities at organ level through whole body exams with Positron Emission Tomography. They were selected patients with normal uptake or a single tumor. In the period 2004-2005, 745 patients were studied. Among then, it was selected 97 adults for the normal uptake control group. The main studies were: intestine; colon, rectum, lung, lymphoma and melanoma, liver, esophagus, gonads and breasts. For "prospective screening", it were selected 20 patients with the identical physical characteristics of the control group. For internal dosimetry, the main organs should be elected according the kinetics of 18F-FDG, either considering normal uptake or pathologies. Absorbed doses due to Computed Tomography and F-FDG uptake were estimated. Comparisons between internal and external exposures, for the same organ, point out higher doses due to external irradiation, except for bladder and kidneys. For individual dose estimation, parameters such the effective half-life should be known and this information may be achieved by an adaptation of the routine protocol. © 2010 C.M.B. Edition. Source

Velasques De oliveira S.M.,Institute Radioprotecao e Dosimetria IRD CNEN | Juliao L.M.Q.C.,Institute Radioprotecao e Dosimetria IRD CNEN | Sousa W.O.,Institute Radioprotecao e Dosimetria IRD CNEN | Mesquita S.A.,Institute Radioprotecao e Dosimetria IRD CNEN | Santos M.S.,Institute Radioprotecao e Dosimetria IRD CNEN
Cellular and Molecular Biology

In Brazil, the radionuclides used for therapy are: 131I, 153Sm, 90Y and 177Lu, both for routine or research protocols. The radionuclide activity excreted by patients may be quantified by bioassay analysis and constitutes a powerful tool for individual treatment planning. The Bioassay Laboratory (LBIOVT) of the Institute of Radiation Protection and Dosimetry (IRD) has equipments for gamma and beta spectroscopy. These systems are calibrated in energy and efficiency using reference sources supplied by the National Laboratory of Radiation Metrology (LMNRI/IRD). The LBIOVT has operational procedures according ISO-ABNT-17025 recommendations and participates of international and national intercomparisons. The patient samples are collected immediately after radiopharmaceutical administrations, at the hospital or at the patient residence, and are handled, stored and transported according national radiation protection regulations. The radionuclide specific activity (Bq/L) is referenced to date and time of excretion, for the estimation of the individual biological half-live. The volume of excreta may carefully manipulated in order to avoid losses and misinterpretation in the activity quantification. The process of the LBIOVT accreditation and its participation in intercomparisons may guarantee the confidence of the results, allowing the minimization of the uncertainties in the individual monitoring. © 2010 C.M.B. Edition. Source

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