Development and validation of an alternative procedure for quantitative quality control analysis of 99mTc-radiopharmaceuticals using a Geiger Müller counter.

BACKGROUND AND OBJECTIVES: In a hospital radiopharmacy with 2a operational level, including the preparation of radiopharmaceuticals from prepared and approved reagent kits, it is common to have a single activimeter or dose calibrator for labeling and fractionation, and to perform the quality controls of the 99mTc-radiopharmaceuticals. In certain cases, the accumulation of radioactive material or accidental contamination of the work area causes the background to exceed the limits to carry out the radiochemical purity analyses and it is necessary to look for viable alternatives. In this work, a Geiger Müller detector (equipped with a probe for measuring surface contamination) frequently used for radioprotection purposes, was validated as an alternative and its performance was compared against the activimeter for 99mTc-radiopharmaceuticals. MATERIALS AND METHODS: Using [99mTc]pertechnetate, systematic studies of error analyses and detector response to activity concentration, activity and measurement time were carried out in liquid matrices and in paper. The results were compared against an activimeter calibrated for [99mTc]Tc. RESULTS: The developed method was used to determine the radiochemical purity of the compounds [99mTc]Tc-MDP and [99mTc]Tc-MIBI by ascending paper chromatography tests, obtaining comparable values to those measured with an activimeter in the same system (within 1% uncertainty) and using the method of vial partitioning in a dedicated equipment. CONCLUSIONS: This work demonstrates that a Geiger Müller detector with a probe for measuring surface contamination can be adequately used to replace other equipment in the control of radiochemical purity in the hospital radiopharmacy.

Stereotactic measurement of the sizes of arteriovenous malformations.

A method has been devised for determining the size and location of an arteriovenous malformation (AVM), or brain tumor, using only two X-ray films taken perpendicular to each other. For this method the requirements are that the locations of the films and the X-ray sources must be known. Such requirements are met by BIPLANE POLY DIAGNOST I, an X-ray machine in which both the films and the X-ray sources are set at constant locations. An analytic geometry approach is used to analyze the images in order to determine both the size and position of phantoms placed in or on an experimental box. Analysis of the films generated by phantoms yields a result accurate to within 0.3 mm.

Prevalencia de la idea y del intento de suicidio en homosexuales egosintónicos

Con el objetivo de determinar la prevalencia de la idea e intento suicida en una muestra de 150 homosexuales egosintónicos, se realizó un estudio descriptivo, observacional, transversal en el terreno, en diferentes centros nocturnos (de asistencia principalmente homosexual) de la ciudad de Santo Domingo. Encontramos una incidencia de un 24.67% con ideas suicidas y 22.6% con intento suicida. Las causas frecuentemente argumentadas para ese hecho resultaron ser los problemas familiares para ambos grupos. Se concluye con la recomendación de realizar un estudio más profundo en torno a la idea y el intento de suicidio en la población general con el fin de contar con su importante y esencial fuente de referencia