Normal reference values for Tc-99m pertechnetate thyroid uptake in northern Iranian population: A single-center experience.

Background: The normal reference values for the thyroid uptake of radioactive iodine and Tc-99m pertechnetate in euthyroid patients vary by geographical location as well as the amount of iodine intake in the diet. The present study examines the normal reference values for thyroid uptake of Tc-99m pertechnetate in the North of Iran. Methods: The participants of this study were 64 patients (all over 20 years of age) who had referred to the Nuclear Medicine Center of the Shahid Beheshti Hospital for thyroid scan over the period between March 2018 and May 2020. It is worth mentioning that relying on laboratory test results, only patients with normal thyroid function were included in this cross-sectional study. Results: The median, the 5th and 95th percentiles and thyroid uptake range of 99mTc-pertechnetate in euthyroid patients were 0.9, 0.6 to 1.8% and 0.54 - 1.80%, respectively. Conclusion: The percentage of uptake in the thyroid gland in each geographical area varies based on race and diet content, so it is necessary to determine the percentage of uptake in each specific region and even check it periodically.

Therapeutic effect of antihypertensive drug on diabetic nephropathy: Functional and structural kidney investigation.

Due to the growth of diabetic mellitus (DM) and diabetic nephropathy as a significant complication for diabetic patients, study on effective treatment with fewer side effects has been fascinated. In this study for the first time carvedilol effects on both function and structure of kidney in diabetic nephropathy treatment were evaluated. Diabetes was induced by injection of streptozotocin (STZ) intravenously in rats and three groups including control, diabetic, and treatment with carvedilol were considered. Biochemical parameters such as, blood glucose level, BUN, creatinine, uric acid, Na+, K+ was determined. Results showed that glucose (516 to 291 mg/dl), BUN (42 to 21.67 mg/dl), creatinine (0.75 to 0.6 mg/dl), uric acid (4.45 to 1.36 mg/dl), and K+ (7.433 to 5.433 mEq/l) level reduced. Decrease in glucose, BUN, creatinine, uric acid, and K+ and increase in Na+ level (138 to 146.33 mEq/l) confirmed therapeutic effect of carvedilol. Furthermore, the histopathological study was done for each group. Histopathological results confirmed the data obtained by biochemical parameters. For further investigation, SPECT imaging with 99mTc-DMSA, which is a gold standard in diabetic nephropathy detection, was done. SPECT imaging showed that accumulation of 99mTc-DMSA was increased in treated group (5 to 25 kcpm) which means the improvement in renal structure in the treated group compare to the diabetic group (5 kcpm). Finally, obtained results confirmed our hypothesis that carvedilol had a therapeutic effect on diabetic nephropathy.

The efficacy of melatonin against radiotoxicity of iodine-131 and its response to treatment in hyperthyroid patients: a randomized controlled trial.

BACKGROUND: Since melatonin is a non-toxic compound with proven radioprotective effects, we aimed to investigate its efficacy in an in-vivo setting in hyperthyroid patients who are treated with iodine-131. This double-blind placebo-controlled study was conducted on hyperthyroid patients referred to nuclear medicine centers in Babol, Iran. We excluded patients suffering from hypertension treated with warfarin, autoimmune diseases, genetic diseases, cancers, smokers, chemical wounded, radiology and radiotherapy workers, and those who were treated with chemotherapy agents. Patients were randomly assigned to receive a capsule containing 300 mg of melatonin powder or a placebo. Just before receiving iodine-131, blood samples were taken from individuals. All 52 female patients received 10 to 20 mCi iodine-131 for treating hyperthyroidism. A second blood sample was taken one hour after the administration of iodine-131. MATERIAL AND METHODS: To determine the chromosomal damages before and after receiving radioiodine, we performed the cytokinesis- block micronucleus assay. Also, at phase 2, 6 months follow-up was performed, in which patients' positive responses to treatment were compared. RESULTS: The findings of this study indicate that the difference in micronucleus formation between the placebo and melatonin groups is not significant. However, a significant difference in the 6 months follow-up revealed that 61.5% and 85.7% of patients had a positive response to treatment in the placebo and melatonin groups, respectively. CONCLUSIONS: As one of the first studies dealing with the human in-vivo assessment on the radioprotective effects of melatonin, it was concluded that melatonin has a non-significant positive impact on reducing the rate of chromosomal damages in hyperthyroid patients treated with iodine-131. Nevertheless, the outcome of treatment was significantly higher by melatonin compared to the placebo group.

Therapeutic effect of cold atmospheric plasma and its combination with radiation as a novel approach on inhibiting cervical cancer cell growth (HeLa cells).

Cervical cancer is one of the important cancers in women. Research on novel treatment approach can reduce the mortality and burden. Although radiotherapy is a common treatment, its negative side effects have concerned physician. In our study, we studied impact of cold atmospheric pressure plasma on the Hela cancer cells, as an alternative treatment. The effect of three different types of such plasma; dielectric barrier discharge (DBD), plasma jet, and afterglow plasma, on the cancer cells were studied. Moreover, some effective operating parameters such as exposure time, applied voltage, composition of working gas in plasma treatment were investigated on the survival of the afterglow plasma. Finally, treatments by the afterglow plasma, gamma radiation (1 Gy), and combination of both were compared. Analysis showed that DBD and plasma jet (direct exposure) effectively killed the cancer cells, even by a minimum applied voltage. But a fraction of the cells survived after the exposure of indirect diffused afterglow plasma. In the case of this plasma, we realized that higher applied voltage and exposure time led to less cell viability. Fewer fractions of survival cells were detected in the case of argon afterglow plasma comparing to oxygen afterglow. Cold atmospheric plasma and its combination with radiation therapy showed a significant decrease in viability of the cells, comparing to the radiation alone. Our research showed that plasma and its combination with radiation therapy have superiority over radiation therapy.

The assessment of radio-adaptive response in graves' hyperthyroidism patients following radioactive iodine uptake.

Low doses of radiation affect the response of cells to higher doses; this phenomenon is called radio-adaptive response, which leads to increased resistance to subsequent higher doses. We have investigated the adaptive response using 0.37 MBq priming dose of I-131 followed by 296-444 MBq challenging dose in peripheral human lymphocyte cells. The study was performed on 42 patients with Graves' disease and 29 healthy adult persons as a control group. The patients were divided into two groups. In the first group, patients were referred for radioactive iodine therapy with a specific dose, and iodine was given to them on the day of referral. In the second group, patients were referred for radioactive iodine uptake and radioactive iodine therapy, and iodine uptake was initially performed, then 24 h later, iodine therapy was done. In both groups, 1 month after treatment, blood samples were taken to cytokinesis-block micronucleus (MN) assay. The number of MN in binuclear lymphocyte cells was counted as an end point test. The mean frequency of MN in first, second, and control groups was 75.86 ± 12.68, 71.45 ± 12.56, and 20.06 ± 7.30, respectively. Our results showed that the frequency of total chromosome aberration in both radiation groups was higher than controls. However, in the first group was higher than another group, but their difference was not statistically significant. According to the results, we cannot approve the hypothesis that 0.37 MBq I-131 administration before iodine therapy could induce a radio-adaptive response in lymphocytes of Graves' patients.

Radio-adaptive Response in Myocardial Perfusion Imaging Induced by Technetium-99m.

PURPOSE OF THE STUDY: Low dose radiation will induce adaptation and following exposure to an adaptive dose, the cells are more resistance to following challenging doses. This phenomenon is known as radio-adaptive response. The aim of this study was to investigate the percentage of apoptotic cells in the peripheral blood samples of the patients which undergo myocardial perfusion imaging (MPI) with technetium-99m (Tc-99m) before thallium scan to assess the induction of radio-adaptive response. MATERIALS AND METHODS: In this study, 97 samples from 74 patients, referred to nuclear medicine center of Mazandaran Heart Hospital for MPI, which had no history of diagnostic, therapeutic, occupational, and radioactive exposures during past 2 years, were provided. The participants were classified into four groups including control, patients which were scanned solely with technetium, the patients which examined by thallium and the last group were the patients that examined by technetium followed by thallium. Then 2 ml Peripheral blood samples were obtained, and after 24 h incubating, the samples were studied by neutral comet assay. Statistical analysis was carried out using Student's t-test along with one-way analysis of variance. RESULTS: The mean percentage of apoptotic cells in the exposed groups were higher than the control. Furthermore, among exposed groups, the apoptotic cells in thallium group were more than others and this index was significantly lower in the group which was undergone technetium administration before thallium scan. CONCLUSIONS: These findings suggest that exposure to Tc-99m could induce a radio-adaptive response against the exposure of thallium-201.

Estimating the population dose from nuclear medicine examinations towards establishing diagnostic reference levels.

PURPOSE OF THE STUDY: This study conducted a review on nuclear medicine (NM) services in Mazandaran Province with a view to establish adult diagnostic reference levels (DRLs) and provide updated data on population radiation exposure resulting from diagnostic NM procedures. MATERIALS AND METHODS: The data were collected from all centers in all cities of Mazandaran Province in the North of Iran from March 2014 to February 2015. The 75(th) percentile of the distribution and the average administered activity (AAA) were calculated and the average effective dose per examination, collective effective dose to the population and annual effective dose per capita were estimated using dose conversion factors. The gathered data were analyzed via SPSS (version 18) software using descriptive statistics. RESULTS: Based on the data of this study, the collective effective dose was 95.628 manSv, leading to a mean effective dose of 0.03 mSv per capita. It was also observed that the myocardial perfusion was the most common procedure (50%). The 75(th) percentile of the distribution of administered activity (AA) represents the DRL. The AAA and the 75(th) percentile of the distribution of AA are slightly higher than DRL of most European countries. CONCLUSIONS: Myocardial perfusion is responsible for most of the collective effective dose and it is better to establish national DRLs for myocardial perfusion and review some DRL values through the participation of NM specialists in the future.

Radioadaptive response in human lymphocyte cells.

The adaptive response (AR) is a phenomenon by which cells exposure to sublethal doses of DNA-damaging agents (non-mutagenic dose of chemical or radiation), known as conditioning treatment (CT), leads to increased resistance to a subsequent exposure to a higher dose of the same or other agents, known as challenge treatment (CR). The adaptive response (AR) induced by radiation in human lymphocytes has been reported in a range of 1-20cGy pre-exposure. In this study, we investigated the adaptive response using 5cGy conditioning dose of gamma rays followed by 2 Gy challenging dose in peripheral human lymphocyte cells. Blood samples were taken from 30 female volunteers and this experiment was carried out by delivering 5 cGy gamma radiation followed by 2 Gy of challenging. Consequently, the number of micronuclei (MN) in binuclear lymphocyte cells was counted as an endpoint. The results showed that the mean frequency of micronuclei in binuclear lymphocytes which have received both conditioning and challenge doses are significantly reduced in comparison to those only exposed to 2 Gy (20.46±2.13, 30.2±3.29) (P< 0.01). The results showed the existence of an in vitro adaptive response in lymphocyte cell exposed to low dose of gamma radiations.

Is Radiosensitivity Associated to Different Types of Blood Groups? (A cytogenetic study).

Many biological factors affect radiosensitivity. In this study, radiosensitivity among the different blood groups was investigated. Peripheral blood sample of 95 healthy people were divided into two parts. One part was irradiated with 2 Gy Co-60 gamma rays and the second one was considered as control. Then all the samples were studied by cytokinesis-blocked micronucleus assay (CBMN assay). Our study showed that the radiosensitivity index of A+ and O+ groups was significantly higher and lower than other blood groups, respectively. It seems that blood type can be used as a radiosensitivity index for determining the given dose to radiotherapy, although extensive studies are necessary.

Prediction of vesicoureteral reflux in children with first urinary tract infection by dimercaptosuccinic Acid and ultrasonography.

OBJECTIVE: Urinary tract infection (UTI) is one of the most common causes of febrile pediatric diseases. Also, vesicoureteral reflux (VUR) is a significant risk factor for UTI. Voiding cystourethrography (VCUG) is the method of choice for evaluation of VUR. This study was done to predict VUR by DMSA scan (technetium 99 m-labeled dimercaptosuccinic acid) and ultrasonography (US). METHODS: In a prospective study, all children with first time acute pyelonephritis were selected and evaluated by DMSA scan and US. Then VCUG was done with negative urine culture. All children with final diagnosis of obstructive congenital anomaly were excluded. The sensitivity, specifity, positive predictive values, negative predictive values, Confidence Interval of DMSA scan and US were calculated for prediction or exclusion of VUR. FINDINGS: Among 100 children with UTI diagnosis, VUR was detected in 39 children and 63 (31.5%) kidneys. DMSA scan was abnormal in 103 (51.5%) units, 45 units had VUR (PPV=44%), 79 units with normal DMSA scan had no VUR (NPV=81%). Of kidney units that were abnormal by DMSA or US, 51 units had VUR. PPV and NPV were 44% and 56%, respectively. CONCLUSION: DMSA scan alone or with US cannot predict VUR (especially low grade VUR). But according to NPV, it seems that absence of VUR can be predicted. So, more studies are needed to determine the usefulness of DMSA scan and US instead of VCUG for detection of VUR.

The study of radiosensitivity in left handed compared to right handed healthy women.

BACKGROUND: Radiosensitivity is an inheriting trait that mainly depends on genetic factors. it is well known in similar dose of ionizing radiation and identical biological characteristics 9-10 percent of normal population have higher radiation response. Some reports indicate that distribution of breast cancer, immune diseases including autoimmune diseases as example lupus, Myasthenia Gravies and even the rate of allergy are more frequent in left handed individuals compared to right handed individuals. The main goal of the present study is determination of radiosensitivity in left handed compared to right handed in healthy women by cytokinesis blocked micronuclei [CBMN] assay.5 ml peripheral fresh blood sample was taken from 100 healthy women including 60 right handed and 40 left handed. The age of participants was between 20-25 old years and they had been matched by sex. After blood sampling, blood samples were divided to 2 groups including irradiated and non-irradiated lymphocytes that irradiated lymphocytes were exposed to 2 Gy CO-60 Gama rays source then chromosomal aberrations was analyzed by CBMN [Cytokinesis Blocked Micronuclei Assay]. RESULTS: Our results have shown radiosensitivity index [RI] in left-handers compared to right-handers is higher. Furthermore, the mean MN frequency is elevated in irradiated lymphocytes of left-handers in comparison with right-handers. CONCLUSION: Our results from CBMN assay have shown radiosensitivity in the left handed is higher than right handed women but more attempts need to prove this hypothesis.

Is there association between handedness and radiosensitivity in breast cancer women?

Radiosensitivity is a biological response to radiation. This response depends on many factors such as radiation factors as well as biological system factors. It is shown that identical doses of radiation for the treatment of Cancer patients produce different biological responses that are assumed to be depend on different specifications of the biological systems. However, by elimination of these factors, people may still show different biological responses such as acute and low responses to radiotherapy in similar doses of radiation. Some reports indicate that breast cancer, immune diseases including autoimmune diseases such as lupus, Myasthenia Gravies and even the rate of allergy are more frequent in left-handed compared to right-handed individuals. The main goal of the present study is determination of radiosensitivity in left-handed compared to right-handed in breast cancer women by cytogenetic assay. Peripheral venous blood samples (10 ml) of 30 breast cancer women (10 left- and 20 right-handed) were divided into two identical parts. One part is exposed to 2 Gy Co-60 gamma rays, and the second part is considered as non-exposed controls. Lymphocytes were cultured in standard media, and cytokinesis blocked to score micronuclei in bi-nucleated cells. The frequency of micronuclei in 1,000 cells in each sample is considered as the rate of radiosensitivity and was compared in left- and right-handed breast cancer women by appropriate statistical analysis. Results showed that radiosensitivity index in left-handers is higher than right-handers also mean frequency of MN in exposed group of left-handers compare to right-handers is elevated. It seems that left-handed breast cancer women are more radiosensitive than right-handed. More investigations on right- and left-handed healthy people are ongoing in our laboratory.

Physical dosimetry and mathematical dose calculation in nuclear medicine: A comparative study.

OBJECTIVES: This paper addresses a comparison between physical dosimetry and mathematical dose calculation in nuclear medicine. MATERIALS AND METHODS: Dose rate was calculated by mathematical external dose calculation formula and by physical dosimetry from the surface of 38 adult patients' body referred to nuclear medicine department. Results of the methods were compared and correlation and regression tests were also performed. RESULTS: Although the physical dosimetry data in this study are in good consistency with other researches, they are much lower than the results of mathematical dose calculation formula. The correlation coefficient between measured dose rate with calculated values derived by mathematical formula was found to be 0.852 (P value=0.148). CONCLUSION: It seems that physical dosimetry data are more accurate than the results of mathematical dose calculation. In case of using mathematical dose calculation formula, other correction factors should be considered and applied for getting reliable data.