Iranian Journal of Nuclear Medicine
Volume:10 Issue: 1, 2002

This is a retrospective study on clinical course and treatment response of patients with thyroid hot nodule, referred to nuclear medicine department of Shariati Hospital from 1360 to 1377. From the total 58 patients with average age of 43 yr and incidence peak of 40 yr, 81% were female and 19% were male. 64% of the patients were thyrotoxic and 36% were euthyroid at presentation. Thyrotoxic symptoms and signs increased with age (P=0.04). 57% of patients received I-131 therapy without premedication. 7% received antithyroid drugs first and then underwent iodine therapy. From 36% of the patients who were euthyroid at presentation, 15.5% became thyrotoxic on follow up studies and received I-131 therapy, but 20.7% remained euthyroid without receiving any therapy. The average of first and cumulative radioiodine doses were 16.9 mci and 21.8 mci, respectively. Treatment response during 6 and 12 month follow up were 80% and 86.7%, respectively. The more administered the first dose, the better was the response (P=0.03). Men appeared to need more I-131 dosage and times of therapy as compared to women. Post radioiodine hypothyroidism incidence was 7.5% during one yr follow up. No meaningful relation was found between times of radioiodine therapy and thyroid or nodule size.

A known case of nephrotic syndrome aged 32 months was admitted to ICU because of loss of consciousness. In physical exam he had tachycardia, tachypnea and hypotension. Lab data showed metabolic alkalosis and hypoxia. In CXR, vascular cut off was seen in right lung and perfusion lung scan showed absence of perfusion in the right lung.Treatment was started with heparin and streptokinase, but unfortunately the patient died 48 hrs after admission.

Nuclear medicine methods have important role in the evaluation of transplanted kidney. In this study 58 99mTc-DTPA scans were performed in 38 patients. This method has 90% sensitivity and 96% specificity. In the cases of normal transplanted kidneys, function correlation between doppler sonography and scanning was more than dysfunctioning kidneys.

It is suggested that sublingual nitroglycerine can improve the ability of T1-201 for detection of viable myocardium. Methods and In a randomized, double blind study, 50 patients who had fixed defects on stress-redistribution scan, were randomized into two groups. In group I, patients received 0.4-0.8 mg sublingual nitroglycerine, before T1-201 reinjection. In group II, reinjection of T1-201 was performed, without any previous intervention. In group I, 11 (44%) of the patients showed improved reversibility after T1-201 reinjection compared with 9 (36%) of group II patients (P=0.56). Moreover, 6 of all patients showed reverse redistribution. This pattern was observed in 4 (16%) of the patients in group I and 2 (8%) of group II patients (P=0.38). Nitroglycerine has no significant effect on detection of reversible myocardium by T1-201 SPECT. Occasionally, T1-201 reinjection causes reverse redistribution, but nitroglycerine has no effect on it.

A 14 years old boy who had a ventriculo-peritoneal shunt since the age of 5 months, was hospitalized due to headaches, nausea, vomiting and abdominal distension. In abdominal CT and sonographic evaluation, pancreatic pseudocyst or mesentric cyst were suspected. Evaluation of the shunt by radionuclide, however, was diagnostic and revealed a pseudocyst at the peritoneal end of the shunt. The patient was successfully treated by surgical intervention.

Skeletal metastasis is one of the most important disabling complications of the malignant diseases. As in general, the survival of patients with osteometastatic lesions is relatively long, an early diagnosis can lead to improve the patient’s life, both quantitatively and qualitatively, and prevent exacerbation of the disease and disabling complications. In this study, 22 patients with established diagnosis of malignant disease and clinical manifestations of skeletal metastasis were evaluated both with 99mTc-MIBI and 99mTc-MDP whole body scans, in two separate phases. Patients’ diagnoses were as following: Small Round Cell Tumor, Breast carcinoma, Nasopharynx carcinoma and Multiple Myeloma. In the first phase of the study a whole body bone scan was performed by IV injection of 740MBq 99mTc-MDP. After a period of 1 week a whole body scan was carried out by 99mTc-MIBI for all the patients. No treatment such as radiation therapy or chemotherapy was done in this 1 week interval. The number and intensity of the scan findings were compared visually, according to the three-phase staging, subsequently. Whole body survey with 99mTc-MIBI in 14 out of 22 patients were positive, demonstrating only 44.4% of bony lesions established on whole body bone scan with 99mTc-MDP. The mean value of intensity of radiotracer uptake, was around 1.5+ (Mild to moderate). On the other hand in 7 patients with positive 99mTc-MIBI scan some hidden soft tissue lesions (Mostly lymph nodes) were detected with intensity of 2+. So this study shows that whole body bone scan is preferable for detection of widespread metastasis comparing with 99mTc-MIBI whole body scan. The singnificance of 99mTc-MIBI scan is mainly limited to some equivocal of soft tissue lesions.

Using Gate’s technique for GFR measurement with Gamma camera, the patient is received 5mCi of Tc-99m-DTPA. By this amount of radioactivity, good quality renal scan is not possible. This study tries to optimize Gate’s technique for GFR measurement during routine renal scan (with 10-15 mCi). Methods and materials: Scanning was performed for 60 seconds from samples of Tc-99m with activities of 3, 9, 12, 15 and 18 mCi in a small syringe, with a 30 cm distance from the detector. Another sample of 12 mCi of Tc-99m was imaged for 5, 10, 15, 20 and 30 seconds. The same sample was again imaged for 10 seconds in different distances (10, 20, 30 and 40 cm) from the detector. Each image was acquired 10 times. Using rectangular region of interest (ROI), total count and maximum count per pixel were recorded for all images. The total count revealed rising in the images form 3 mCi to 15 mCi samples while declining thereafter, suggesting paralysis of the Gamma camera in high activities. Maximum count per pixel was 32767 (2 in 15 power minus one) in all images except for the 3 mCi sample image, suggesting saturation of the pixels in high activities. Also saturation of the pixels was note in images of 12 mCi sample for more than 15 seconds. No saturation of pixels was noticed within 20-40 cm distance from the detector. By optimization of the Gate’s technique for GFR measurement, GFR can be calculated during routine renal scan. We suggest using 10-15 mCi of Tc-99m-DTPA, with 5-15 seconds preinjected syringe count, 30 cm distant from the detector. Comparison of GFR calculation using suggested technique with GFR estimation by creatinine clearance in 9 patients, resulted in a significant and good correlation coefficient (R=0.883, P=0.005).

Discrepancy between pre & post treatment WBSs (Low dose & high dose, respectively) is reported. The aim of this study was determination the post-treatment WBS role in the diagnosis of lesions not identified by the pretreatment one. In this study 94 patients (pts) with DTC were evaluated. The results of pre & post treatment WBSs were compared. Overall, 25.6% of pts revealed more positive lisions in comparison with their pretreatment WBS. The increase in positive results in pts<35 yr was 36% and in pts>35yr was 25%. In males and females, the increased values were 33.3% & 23.58% respectively. In all types DTC post-treatment WBS revealed more involvement. In cases limited to thyroid, with capsular invasion and with lymph node involvement the increased values were: 20.5%, 28.5% & 35.7%, respectively. In cases with TSH<30m U/L, 53.8% & in cases with TSH>30 mU/L, 22.2% more positive lesions were observed. Pts with Htg<10 ng/ml & >10 ng/ml, post-treatment WBS revealed more lesions in 28% & 21.8%, respectively. Post-treatment WBS improves rate of detection of thyroid cancer lesions. In our study this was especially true in cases with TSH<30 mU/l & Pts younger than 35yr.

Abstractcontamination and exposure for those who come in contact with them, such as nuclear medicine technologists, relatives and nurses. Therefore, the measurement of external radiation dose from these patients is necessary. In this study, the dose rates at distances of 10, 50 and 100cm from 70 patients who received diagnostic amounts of ²º¹T1-chloride and 99mTc-MIBI was measured. The results showed that the maximum external radiation dose rates for ²º¹T1 and 99mTc were 18.4 and 75.0 μSv.h^-1, respectively, at 5 cm distance from the patients. The average radiation dose received by nuclear medicine technologists, considering their close contact during one working day was 12.5±3.4 μSv. The highest received dose was 22.7 μSv, which was well below the acceptable dose limit.

Radionuclidic techniques may provide assessment of glomerular filtration rate (GFR) effective renal plasma flow (ERPF) or individual renal function. Several agents were available for determination of these parameters such as ¹³¹I-OIH (O-iodohippurate) and different derivatives of DADS (Diamidodisulfur). OIH has the disadvantage of imparting a relatively high absorbed radiation dose to the patient at low diagnostic doses. First experiment with 99mTc-MAG3 in mice and rats indicated an essentially complete renal elimination with faster excretion rates and higher excretion efficiencies than for OIH. The superior physical properties of 99mTc for gamma camera imaging replaced 99mTc-MAG3 as a renal tubular agent. Here in, we report synthesis, formulation and quality control of 99mTc-MAG3 as a renal tubular 99mTc-radiopharmaceutical kit. The Bz-MAG3 and its precursors were characterized by FTIR spectroscopy.

By identifying the effect of any parameter such as distance, attenuation and scattering on the Line Spread Function (LSF), one can compensate the quantitative and qualitative destructive effect of such parameters by deconvolution method. Using a 99mTC line source, this study was performed on a single head ADAC SPECT system operating in planar mode. Variation of FWTM and FWHM and LSFs as a function of source to collimator distance in air, source depth in scattering medium (water) and the combined effects of distance and depth of the source in scattering medium were investigated. The equations of spatial resolution (FWHM) with the above mentioned conditions were found to R1=0.07481+4.0862mm for I≥100mm for and Rd=0.0102d+10.962mm for d≥0mm and Rh=0.2512h–14.609mm for h≥100mm respectively. Where R1, Rd and Rh are spatial resolution (FWHM). I and h are the source to collimator distances in air and scattering medium respectively and d is the source to collimator distance in the scattering medium eliminating distance effect on FWHM. These variations were found to be linear having different slopes. The results showed that increasing source to collimator distance in air degrades the spatial resolution considerably, i.e. an increase of 10 cm degrades the spatial resolution by 54%. In this case the variation in FWTM is almost similar to FWHM. By increasing the source depth only in scattering medium (Eliminating the effect of source distance) no noticeable change on spatial resolution is seen, but due to accumulation of scattered photons under both wings of the LSF, the increase in FWTM is more intense than FWHM. This phenomena causes the broadening of sharp edges which in turn leads to loss of contrast and errors in determining the size of lesions and the uptake of activity in ROI.