0

Fredy Julián Gómez Grance

Nacional de Asunción University, Paraguay

Title: PHYSICAL DOSIMETRY OF THE TREATMENT OF HYPERTHYROIDISM WITH I-131 COMPARED TO THE COMET'S ASSAY

Abstract

In hyperthyroidism, the MN doctor prescribes the activity of I131 using the Marinelli ‘404’ equation, in this sense, patient-specific dosimetry has not been implemented in the region. This work shows the possibility of performing post-treatment dosimetry in 50 patients, accompanied by cytogenetic evaluation with the comet assay (EC), the results are consistent with the compartmental model of internal dosimetry. An image dosimetry conjugated with a SPECT and a Pinhole collimator was implemented, using the MIRD methodology. Fifty patients were sampled, obtaining the conjugated images of the thyroid in five samples spaced during 6, 12, 24, 48, 96 hours and different peripheral blood samples were obtained from the fifty patients in 3 days. Once the images were obtained, the relative count number of the images was determined by the free program ImagenJ 1.51K, these values ??were represented as a fraction of incorporation as a function of time, to which a least-squares approximation was applied, the area under the curve was determined, which represents the activity of I131 accumulated during the residence time, with which the absorbed dose was determined. The cytogenetic damage values ??were determined with the EC. Some patients do not follow the retention curve considered ideal, it could be observed that in several of them the thyroid did not normally capture I131, so the images were distorted with respect to the normal thyroid. In general, the doses are greater than the doses estimated as euthyroid doses, which for women of childbearing age means complications to procreate. The physical dosimetry shows a great coherence with the values ??of residence time in blood determined with the EC and, according to the experience acquired, the feasibility of applying a specific dosimetry for the patient has been demonstrated.

Biography

Berg, G., Michanek, A., Holmberg, E., & Fink, M. (1996). Iodine- 131 Treatment of Hyperthyroidism: Significance of Effective Half-life Measurements. THE JOURNAL OF NUCLEAR MEDICI, 228-232. Puebla, L., Torres, S., & Fernández, V. (2015). Efectos biológicos de los Rayo-X en la práctica de Estomatología. Revista Habanera de Ciencias Médicas , 337-347. Siegel, J., Thomas, S., & Stubbs, J. (1999). MIRD Pamphlet No. 16: Techniques for Quantitative Radiopharmaceutical Biodistribution Data Acquisition and Analysis for Use in Human Radiation Dose Estimates. THE JOURNAL OF NUCLEAR MEDICINE, 37-60. Autoridad Regulatoria Nuclear. (1998). Curso de Post-Grado en Protección Radiológicay Seguridad Nuclear (Vol. 1). Buenos Aires, Argentina: ARN.