Determination of [99]Mo contamination in [99m]Tc elute obtained from [99]Mo / [99m]Tc- generator

[99m]Tc is a widely used radioisotope in nuclear medicine centers which is obtained by elution from Mo-[99]/Tc-[99m] generators. Usually the generators are either supplied by the Iran Atomic Energy Agency or by private companies from foreign countries. In this study we have measured [99]Mo contamination in [99m]Tc elute from different generators in a period of one year. The radionuclide impurity of the [99m]Tc elute were studied in two types of radionuclide generators [A: produced in Iran and B: imported from other country]. In-vitro measurements were performed using dose calibrator. Direct measurements were made, using a standard canister at the time of milking of the generators and also in subsequent hours after milking. The results showed a mean of [99]Mo impurity in generators A and B to be 0.00932 +/- 0.0043 and 0.0170 +/- 0.0127 respectively. Although the results showed that the [99]Mo contamination in [99m]Tc elute was lesser than the maximum accepted activity limit of 0.015%, the difference in these two types may reflect different methods of productions of generator, as well as the quality control procedures. The mean of [99]Mo contamination in generators produced in Iran Atomic Energy Organization was lesser than generators imported from foreign origin

Diuretic effect on the measurement of differential renal function using 99m Tc-DMSA in patients with hydronephrosis

It has been suggested that calculation of differential renal function [DRF] using 99mTc-DMSA may lead to overestimation of the function of an obstructed kidney. The aim of this study was to evaluate the effect of diuretic administration on the determination of DRF using 99mTc-DMSA scintigraphy in patients with dilated pelvis. Thirty three patients, aged from 2 months to 66 years [19.27 +/- 20.83 years, 22 males, 11 females], in whom unilateral hydronephrosis had been documented by ultrasonography and diuretic renography were included in the study. 99mTc-DMSA scintigraphy was performed in all patients 3 hours after tracer injection. Immediately after the standard study, furosemide was injected in all patients, and 30 min later anterior and posterior images were obtained. DRF was calculated for each patient and from each 99mTc-DMSA study by using the geometric mean method. We did not observe any significant difference in all patients between the DRF values obtained before and after diuretic administration [the DRF value of the affected kidney was thus taken into account][P=0.35]. When we compared DRF values obtained from standard and from diuretic DMSA studies, the mean of the differences was only 0.18% and the SD was only 1.09%. In 17 patients [group1], diuresis renography revealed an obstructive curve pattern while 16 patients [group 2] had a nonobstructive dilated renogram curve pattern. There were again no significant differences between DRF values obtained before and after diuretic injection in each group. In view of our study, diuretic administration seems to be an unnecessary intervention because it has no effect on the accuracy of DRF measurements using 99mTc-DMSA scintigraphy in patients with a dilated collecting system whether it is obstructed or not

Complications after dipyridamole infusion in myocardial perfusion SPECT and correlation with homodynamic changes

In Iran dipyridamole is the main agent used for coronary dilatation before myocardial perfusion SPECT. This study tries to evaluate the side effects after dipyridamole infusion and its relation with hemodynamic changes. We studied 300 patients who referred to myocardial perfusion scan. The exclusion criteria were: 1] AV block degree 2 or more, 2] Asthma 3] Sick sinus syndrome 4] LV EF<25%. Dipyridamole infusion was done with a dose of 0.568 mg/kg of body weight for 4 minutes and blood pressure and pulse rate were measured before infusion of dipyridamole and 2 minutes after termination of infusion. Patients were asked for any side effects and any complaints were recorded. Relationship between these side effects and age and sex of patients as well as hemodynamic changes were studied. 148 female and 152 male patients studied with a mean age of 55.9 years [11.1]. After dipyridamole infusion 79.3% of patients had at least one symptom, with headache [50%] and sweating [3%], the most and the least prevalent symptoms respectively. Mean heart rate increment was 8.8 and 9.2 beat per minute in female and male respectively [P=0.59]. Mean systolic blood pressure decrement was 8.5 [8.6] and 9.6 [7.1] mmHg in male and female respectively [P=0.21]. Diastolic pressure decrement was 4.6 [6.7] and 6.8 [6.3] mmHg in male and female respectively [P=0.003]. Headache and flashing were more frequent in female patients [P=0.004]. Other symptoms like dizziness, dyspnea, chest discomfort and abdominal discomfort were not different between female and male patients [P>0.08]. After dipyridamole infusion, nonspecific side effects are frequent. Headache and flashing is more frequent in female patients. Flashing is related to decrement in diastolic blood pressure