Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy

Objective[s]: radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right-sided cancer

Methods: to minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease [based on Framingham risk scoring] were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy [CRT] to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy [in 2 Gy daily fractions] over a 5-week course. The same dose-adjusted chemotherapy regimen [including anthracyclines, cyclophosphamide and taxol] was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion

Results: a total of 71 patients with a mean age of 45.3 +/- 7.2 years [35 patients with leftsided breast cancer [exposed] and 36 patients with right-sided cancer [controls]] were enrolled. Dose-volume histogram [DVH] [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls [P=0.02, Odds ratio=1.46]. In semiquantitative segmental analysis, only apical [28.6% versus 8.3%, P=0.03] and anterolateral [17.1% versus 2.8%, P=0.049] walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score [SSS] of>3 was observed in twelve cases [34.3%], while in five of the controls [13.9%],[Odds ratio=1.3]. There was no significant difference between the groups regarding left ventricular ejection fraction

Conclusion: the risk of radiation induced myocardial perfusion abnormality in patients treated with CRT on the left hemi thorax is not low. It is reasonable to minimize the volume of the heart being in the field of radiation employing didactic radiation planning techniques. Also it is advisable to screen these patients with MPI-SPECT, even if they are clinically asymptomatic, as early diagnosis and treatment of silent ischemia may change the outcome

Synthesis and preliminary evaluation of a new[99m]Tc labeled substance P analogue as a potential tumor imaging agent

Neurokinin 1 receptors [NK[1]R] are overexpressed on several types of important human cancer cells. Substance P [SP] is the most specific endogenous ligand known for NK1Rs. Accordingly,a new SP analogue was synthesized and evaluated for detection of NK[1]R positive tumors.[6-hydrazinopyridine-3-carboxylic acid [HYNIC]-Tyr[8]-Met[O][11]-SP] was synthesized and radiolabeled with 99mTc using ethylenediamine-N,N-diacetic acid [EDDA]and Tricine as coligands. Common physicochemical properties of radioconjugate were studied and in-vitro cell line biological tests were accomplished to determine the receptor mediated characteristics. In-vivo biodistribution in normal and tumor bearingnude mice was also assessed. The cold peptide was prepared in high purity [>99%] and radiolabeled with [99m]Tc at high specific activities [84-112GBq/ micro mol] with an acceptable labeling yield [>95%]. The radioconjugate was stable in-vitro in the presence of human serum and showed 44% protein binding to human serumalbumin. In-vitro cell line studies on U373MG cells showed an acceptable uptake up to 4.91 +/- 0.22% with the ratio of 60.21 +/- 1.19% for its specific fraction and increasing specific internalization during 4 h. Receptor binding assays on U373MG cells indicated a mean Kd of 2.46 +/- 0.43 nM and Bmax of 128925 +/- 8145 sites/cell. In-vivo investigations determined the specific tumor uptake in 3.36 percent of injected dose per gram [%ID/g] for U373MG cells and noticeable accumulations of activity in the intestines and lung. Predominant renal excretion pathway was demonstrated. Therefore, this new radiolabeled peptide could be a promising radiotracer for detection of NK[1]R positive primary or secondary tumors

Comparison of transient ischemic dilation ratios in SPECT and SPECT-CT myocardial perfusion imaging in the low pre-test probability group

The main purpose of this study was to compare transient ischemic dilation [TID] ratios in SPECT-low dose CT and SPECT Myocardial Perfusion Imaging [MPI] by application of different quantitative programs and quantify the possible shift in the upper normal limits of TID ratio in the SPECT-CT MPI. 149 Patients with low pre-test probability for coronary artery disease [CAD], based upon Diamond and Forrester method entered the study. Each patient underwent both attenuation correction [AC] SPECT-CT MPI and non attenuation correction [NAC] SPECT MPI [two day Tc-99m sestamibi stress-rest protocol]. Normalcy rates were also calculated and compared. The comparison was based on both visual interpretation and quantitative analysis. In the low pre-test probability group visual interpretations lead to a statistically significant improvement in normalcy rate in the SPECT-CT acquisition compared to the SPECT MPI. Regardless of the stress type and software programs used, no significant difference was noted in the upper normal limits of the TID ratios between the AC and NAC acquisitions. The study showed superiority of SPECT-CT MPI to SPECT MPI in terms of normalcy rate. We also propose new upper normal limits of TID ratios for different sets of acquisition-gender-stress modality-software programs

Accuracy of modification of diet for renal disease and cockcroft-gault equations as compared to the radioisotope double sample method: a study in patients with acute renal failure

We intended to assess the accuracy of re-expressed Modification of Diet for Renal Disease [MDRD] and Cockcroft-Gault [CG] equations to estimate glomerular filtration rate [GFR] in chronic kidney disease in two different etiologies of acute renal failure [ARF]: acute tubular necrosis [ATN] and acute glomerulonephritis [AGN]. Patients admitted for ARF or the patients complicated with ARF during the course of their hospitalization were enrolled to the study [n=21; 14 females and 7 males; 11 ATN and 12 AGN]. When the plasma creatinine reached a steady state [DPSM] using [99m]Tc-DTPA. GFR was also estimated by MDRD [GFRMDRD] and CG [GFRCG] equations. The patients aged 44.8 +/- 19.5 years and weighted 67.8 +/- 10.7kg. GFRDPSM [32.9 +/- 14.7 ml/min] was statistically different from the GFRMDRD [11.6 +/- 8.2 ml/min; pCG was lower than GFRDPSM in patients with either ATN [16.5 +/- 12.5ml/min and pDPSM and GFRMDRD [r=0.34; p=0.13] but GFRDPSM and GFRCG values were correlated [r=0.48; p=0.03]. Out of subjects with GFRDPSM >30, 92.3% had GFRMDRDCG Our results indicate that MDRD and CG equations were substantially inaccurate in patients with ARF. More precise methods of GFR evaluation is recommended in these patients

Optimum conditions of radioligand receptor binding assay of ligands of benzodiazepine Receptors

To obtain drugs which are more selective at benzodiazepine [BZD] receptors, design and synthesis of functionally selective ligands for BZD receptors is the current strategy of our pharmaceutical chemistry department. The affinity of newly synthesized ligands is assessed by radioligand receptor binding assays. Based on our previous studies, 2-phenyl-5-oxo-7-methyl-1,3, 4-oxadiazolo[a,2,3]-pyrimidine [compound A] was chosen for design and synthesis of new triazole derivatives as GABA[A] BZD receptor agonist. The cortical membrane of male Sprague-Dawley rats was prepared as the source of the BZD receptors. Different concentrations of membrane protein and [[3]H]-flumazenil were incubated at room temperature at different time periods to reach the steady-state. To saturate the receptors, increased amounts of radioligand were incubated with membrane protein. The bound and un-bound ligands were separated by centrifugation. The affinity of compound A was measured in competition studies at optimum conditions by displacement of [[3]H]-Flumazenil from rat cortical membrane. Based on results, the optimum conditions of radioligand receptor binding assay of benzodiazepines were 35 min incubation of ligands with 100 micro g cortical membrane protein and 8.6 x 10[-5] nmole [3]H-flumazenil in a final volume of 0.5 mL Tris-HCl buffer [50 mM, pH 7.4] at 30 [degree sign]C. The binding parameters of [[3]H]-flumazenil, B[max] and K[d] were determined through saturation studies as 0.638 +/- 0.099 pmol/mg and 1.35 +/- 0.316 nM respectively. The affinity of compound A was 1.9 nM comparable with diazepam [1.53nM]. This finding makes the compound an interesting lead for further optimization. Starting from this compound, new ligands were synthesized and screened in-vitro by competitive binding assays

Effectiveness and complications of [153]Sm-EDTMP in palliative treatment of diffuse skeletal metastases

The aim of the present study was to evaluate the efficacy and safety profile of bone palliative therapy following administration of [153]Sm-EDTMP in patients with intractable metastatic bone pain. Sixteen patients [9 male, 7 female] aged 29-80 years [57.3 +/- 16.7 years] with severe metastasis-related bone pain resistant to analgesic medications were enrolled in the study. All patients having multiple bone metastases, positive bone scans, and estimated life expectancy of more than 2-3 months were entered the study. All patients received intravenous injection of 1.5 mCi [56 MBq]/kg of [153]Sm-EDTMP. Four subscales for the intensity of pain were recorded: one as the present pain score [PPS] and the other three as maximum pain score [Max PS], minimum pain score [Min PS] and average pain score [APS] over the last 24 hours. Also the mean value of these 4 subscales was calculated as the mean total pain score [MTPS]. The pain mental interference [PMI] was also assessed in 9 separate. Seven patients with breast cancer [43.75%], seven with prostate cancer [43.75%], one with papillary thyroid carcinoma [6.25%] and one with malignant paraganglioma [6.25%] were included in the study. A significant response to therapy, i.e. 2-point reduction in pain score and/or remarkable reduction [>/=25%] in the equivalent narcotic dose, was observed in 11 out of 16 patients [68.7%] by the 2nd week and in 12 patients [75%] by the 8[th] week. Regarding the palliative response to treatment and equivalent narcotic dose reduction, no significant difference between two major types of underlying malignancies [breast and prostate cancer] was found. There was no significant difference regarding response to therapy between two genders and among different age groups. The severity of bone marrow suppression was graded

[99m]tc-ubiquicidin [29-41], a promising radiopharmaceutical to differentiate orthopedic implant infections from sterile inflammation

Ubiquicidin [UBI] [29-41] is a synthetic cationic antimicrobial peptide that preferentially binds to bacterial cell membrane at the site of infection. We aimed to assess diagnostic value of [99m]Tc-UBI [29-41] as a radiopharmaceutical in differentiation of bacterial infection from sterile inflammation in suspected orthopedic implants. Nine patients suspected for orthopedic implant infection, all males with the mean age of 41.6 +/- 20.9 years, were studied. A dose of 10 MBq/Kg [range: 555-740 MBq] [99m]Tc-UBI [29-41] was injected intravenously. A dynamic study followed by static whole body imaging at 30, 60 and 120 min post-radiotracer injection was acquired. Periprosthetic tissue culture was considered the closest test to a gold standard for diagnosing infections and scintigraphic scans were categorized as true- or false-positive and true- or false-negative, considering the bacterial culture as the gold standard. No adverse reaction was observed during or after the radiotracer injection days. There were five true positive, four true negative and no false positive and false negative scans. Sensitivity, specificity, positive predictive value [PPV] and negative predictive value [NPV] were all calculated as 100%. We found a high diagnostic accuracy for [99m]Tc-UBI [29-41] scintigraphy in differentiation of bacterial infection from sterile inflammation in suspected orthopedic implants. Therefore, [99m]Tc-UBI [29-41] scintigraphy might be potentially recommended as a safe and promising imaging modality in these settings. However, further studies on a larger number of patients and different pathologies are still needed

Evaluation of myocardial perfusion and function after kidney ? transplantation by Gated SPECT myocardial perfusion scintigraphy

The aim of this study was to evaluate the effect of successful kidney transplantation [KT] on myocardial perfusion and left ventricular function by both qualitative [visual] interpretation and semiquantitative parameters, using myocardial perfusion scintigraphy with gated-single photon emission computed tomography [gated-SPECT] in patients suffering from end-stage renal disease. From a total of 38 patients who were candidates of KT, twenty-six patients [16 female, 10 male, mean age: 47.5 yr, range: 24-64 yr] who had successful KT were included. Myocardial perfusion scintigraphy was performed by Gated Single Photon Emission Computed Tomography [Gated-SPECT] method, before and after surgery [mean: 24 months]. Perfusion and function status was evaluated by qualitative and semiquantitative parameters. Our data showed qualitative evidence of perfusion and functional abnormality in pre-transplant scans as follows: Abnormal perfusion in left anterior descending [LAD], left circumflex [LCX] and right coronary artery [RCA] territories in 42.5%, 53.8% and 65.4% of cases, respectively; dilation in 57.7% and inhomogenity of uptake in 53.8% of cases. However no statistically significant change was noted after transplantation, i.e. p value for all semiquantitative values including summed stress score [SSS], summed rest score [SRS] and summed difference score [SDS], summed motion score [SMS], summed thickening score [STS], ejection fraction [EF], end diastolic volume [EDV], end systolic volume [ESV], and stroke volume [SV] was greater than 0.05. Renal transplantation may not have considerable long term effect on myocardial perfusion and function in patients with chronic renal failure. This could be due to either non-reversible myocardial changes or continuing effect of degrading factors on the myocardium

Additive clinical value of bone scintigraphy in patients with malignant tumors with absence of localized bone pain: a report on most common sex-related cancers

Almost all malignant tumors have the potential to eventually produce bone metastasis. The aim of the current study was to report the distribution pattern and imaging characteristics of bone metastases detected by conventional whole body bone scintigraphy in patients with different types of malignancies and to assess their relationship with the complaint of bone pain. As a cross-sectional study, 146 consecutive patients with histologically proven cancer who were referred for the assessment of possible bone metastatic involvement were investigated by 99mTc-Methylene Diphosphonate [MDP] whole body scintigraphy. A total of 146 patients [79 male and 67 female; mean age: 59.59 +/- 11.95] were enrolled, of which 71 [48.6%] patients had prostate cancer, 61 [41.8%] breast cancer, 6 [4.1%] gastric malignancy, and 8 [5.5%] miscellaneous cancers. The most frequent sites of bone metastases [vertebrae, pelvis and sternum] demonstrated more intense radiotracer uptake. Most of patients [58.5%] with bone metastasis due to breast cancer reported no localized bone pain. Also in the subgroup with prostate cancer, no significant association was noted between the site of bone metastases and location of the pain perception in most of the skeletal zones. Bone scintigraphy [by determining the specific pattern of bone metastases in different tumor types] may help physicians provide better care for patients who suffered from metastatic cancer. On the other hand, in view of the fact that no reliance can be placed on clinical symptoms and the patients' report of bone pain, bone scintigraphic data can be included in the follow-up evaluation of patients suspected to have bone metastasis, even in the absence of bone pain

Radioiodine therapy for hyperthyroidism

Radioiodine therapy is the safest, simplest, least expensive and most effective method for treatment of hyperthyroidism. The method employed in this research was a systematic bibliographic review, in which only valid studies or the clinically detailed enough open-labeled studies using validated scales were used. Iodine-131 [I-131] acts by the destructive effect of short-range beta radiation on thyroid cells. Indications for radioiodine therapy include toxic nodules [in which I-131 is the first choice of treatment], recurrent hyperthyroidism after antithyroid treatment or surgery, intolerance to antithyroid therapy due to side-effects and patient preference. Due to difficulties in previous methods for dose determination, fixed dose method of I-131 is now considered the best practical method for radioiodine therapy in primary hyperthyroidism. Absolute contraindications for radioiodine treatment are pregnancy and lactation. In pediatric patients, radioiodine therapy can be used, but is mainly considered in recurrent toxic goiter and when antithyroid medication is ineffective. There is no clear evidence indicative of carcinogenic or teratogenic effect of this agent

value of myocardial perfusion imaging with Tc-99m MIBI for the prediction of perfusion improvement after percutaneous transluminal coronary angioplasty

Percutaneous transluminal coronary angioplasty [PTCA] is an effective method for revascularizing of stenotic coronary vessels. Lack of response to this treatment, either in symptomatic or asymptomatic patients, is usually due to incomplete revascularization, restenosis, and/or irreversibility of myocardial perfusion. Introduction of a noninvasive method with high predictive value for diagnosis of reversibility in ischemic myocardium is of high importance to determine the patients who will benefit from PTCA. Sixty patients with one or two vessel disease, who were candidates for PTCA and had a successful PTCA [proved by post-revascularization angiography], enrolled the study. For all patients myocardial perfusion within 6 months after PTCA. The predictive values of pre-PTCA scan for the diagnosis of reversibility and prediction of perfusion improvement after PTCA were evaluated. Perfusion improvement after PTCA was noted in 52 of 60 patients [86.7%]. The positive predictive value of pre-intervention MPI for diagnosis of reversibility was 94.3% and the corresponding negative predictive value was 71.4%. Myocardial perfusion imaging may play an important role for accurate prediction of perfusion improvement after percutaneous transluminal coronary angioplasty

McCune-albright syndrome: report of a case

A 29-year old female with bone pain and history of precocious puberty was referred for bone scintigraphy. On physical examination caf‚ au lait macular spots were noted on her neck, buttocks and left leg. Bone scan showed multiple areas of intense increased activity which was in favour of polyostotic fibrous dysplasia. Considering the presence of polyostotic fibrous dysplasia, precocious puberty and caf‚ au lait macular spots, MacCune-Albright syndrome was confirmed in this patient

Evaluation of [99m]Tc-Ubiquicidin 29-41 Scintigraphy in Differentiation of Bacterial Infection from Sterile Inflammation in diabetic foot

Ubiquicidin [UBI] 29-41 is a synthetic antimicrobial peptide that binds with the microbial cell membrane at the location of infection. This study was conducted to evaluate its probable efficacy as an infection-imaging agent with potential to differentiate bacterial infection from sterile inflammation in humans. Fifteen diabetic foot patients [10 males and 5 females] with suspected bacterial infection, prior to starting antibiotic treatment, were selected for this study. First a routine three phase bone scan and later a [99m]Tc-UBI scan was performed for all the patients. 555-740 MBq of [99m]Tc-UBI was injected intravenously. A 10 minute dynamic study was followed by spot views of the suspected region of infection and corresponding normal areas [liver and kidneys] at 60 and 120 min. Whole-body anterior and posterior images were also acquired. To interpret the studies as positive or negative, visual score [0 -3] was used, with scores of 0 [minimal or no uptake; equivalent to soft tissue] and 1 [mild; less uptake than in liver] being considered negative and scores of 2 [moderate; uptake equal to or greater than that in liver] and 3 [intense uptake equal to or greater than that in kidneys] being considered positive. Of 15 studies performed with [99m]Tc-UBI, all had positive bacterial cultures. The result of bone scan was positive for osteomyelitis in 12 patients [80%]. [99m]Tc-UBI Scintigraphy was positive in 6 patients, but negative in nine. The sensitivity of [99m]Tc-UBI for detection of infection was therefore 40%. From 12 patients who had positive bone scans, only 6 had a positive [99m]Tc-UBI [50%] indicating the sensitivity of 50% for [99m]Tc-UBI in osteomyelitis cases. 99mTc-UBI was not positive in any patient who had evidence of soft tissue infection in the bone scan. Although [99m]Tc-UBI 29-41 was well tolerated by all the patients without any side effects, considering low sensitivity of this agent, this radiopharmaceutical is not of great value for diabetic foot infection diagnosis

Bone scan with incidental visualization of the entire colon

A 57-year-old male with history of prostatectomy, cyctectomy, cecal urinary diversion for invasive prostate cancer and with a recent rise in PSA level, was referred for bone scintigraphy to rule out osseous metastatic disease. An interesting finding was abnormal tracer accumulation throughout the large bowel, which was proved to be due to urinary diversion

Giant cavernous hemangioma on Tc-99m RBC Scan

A 36-year-old woman with right upper quadrant abdominal pain since three months previously and no other significant medical history was referred for evaluation of an abdominal mass. Upon clinical examination, a large palpable mass in the mid -upper abdominal area was noted. Abdominal ultrasound and spiral CT-scan showed a large hepatic mass in the left liver lobe. The patient was referred for Tc-99m labeled RBC scintigraphy to assess the possibility of presence of liver hemangioma. The radionuclide imaging confirmed the diagnosis of hemangioma which in this case, the huge size of the lesion was of interest

pattern of brain perfusion SPECT in non-medicated schizophrenic patients

Studies with single photon emission computed tomography [SPECT] have revealed inconsistent changes of regional cerebral blood flow [rCBF] in schizophrenia. Some studies investigated the rCBF and its relationship with psychopathology, positive and negative symptoms in treated patients. However, there is a little information about the pattern of rCBF in recently untreated or never treated schizophrenic patients. The aim of this study was to evaluate the pattern of rCBF of the drug-na‹ve or drug free schizophrenic patients. Thirty-three patients with schizophrenia participated in the study. For each subject, the regional brain perfusion was evaluated with SPECT and the clinical state was assessed according to PANSS and CGI in a medication-free state. Also a group of 12 cases without any history of neurological or psychological disorder was enrolled as a control group for comparing of the SPECT data. Regional perfusion indices [RPI] were defined as mean count per pixel in each of 25 brain regions normalized to the mean count per pixel of the whole brain. The RPI patterns were compared in control and patient subjects. In comparison with control subjects, the RPI of the anterior cingulate and inferior parts of the prefrontal and temporal cortices of the schizophrenic patients are significantly higher while the RPI of the occipital and parietal regions are unilaterally lower. Different schizophrenic patients showed hyperperfusion as well as normal or hypoperfusion in different regions of the brain cortex. However, hyperperfusion rather than hypoperfusion mainly is seen in the inferior prefrontal and temporal regions, while hypoperfusion patterns are more prominent in the cerebellar, occipital, parietal and dorsolateral prefrontal cortices. Different patterns of brain perfusion are seen in drug-free or drug-naive patients with schizophrenia. Hyperperfusion in the frontal and temporal regions and hypoperfusion in the cerebellar, parietal and dorsolateral prefrontal cortices are the most predominant abnormal patterns in these cases

Myocardial perfusion scan accuracy in detection of coronary artery disease: comparison with exercise stress test

In patients with coronary artery disease [CAD] noninvasive evaluation for detection of ischemia is important to avoid invasive interventions like angiography. Exercise stress test is conventionally the first study used in evaluation of CAD. Considering the noninvasive nature of the myocardial perfusion scan, we decided to compare its accuracy with stress test. Patients with chest pain, and intermediate risk for CAD underwent stress test with Bruce standard method by treadmill, and myocardial perfusion SPECT scan with Tc-99m MIBI and the results were compared to the angiography as the gold standard. Analysis of the data was performed by SPSS 11.5 soft ware. The study was performed on 89 patients [mean age: 55.5, min: 29 max: 80] including 53 man and 36 women. Exercise stress test had 54% sensitivity, 65% specificity, 68% PPV, 50% NPV, while for myocardial perfusion scan sensitivity was 94%, specificity 94%, PPV 96%, and NPV 92%. Correlation between involved walls in myocardial perfusion scan with stenotic artery in angiography was 77.6%, while this value was 32.7% for exercise stress test. There was also relationship between degree of stenosis determined by angiography and severity of ischemia detected by myocardial perfusion scan. Myocardial perfusion scan is of great value in detection of CAD with sensitivity and specificity far better than exercise stress test. It is suggested that this noninvasive study being considered the first diagnostic method for patient at risk for coronary artery disease

Validation of 13C-urea breath test with non dispersive isotope selective infrared spectroscopy for the diagnosis of helicobacter pylori infection: a survey in Iranian population

The urea breath test [UBT] which is carried out with [13]C or [14]C labeled urea is one of the most important non invasive methods for detection of Helicobacter pylori infection. Application of [13]C-UBT is becoming increasingly popular because of its non radioactive nature which makes it suitable for diagnostic purposes in children and women of child bearing ages. While isotope ratio mass spectrometer [IRMS] is generally used to detect [13]C in expired breath, this instrument is expensive and recently non dispersive isotope selective infrared [NDIR] spectroscopy which is a lower cost technique has been employed as a reliable counterpart for IRMS in small clinics. The aim of this study was to assess the validity of NDIR spectroscopy technique in Iranian population in comparison with histological examination, rapid urease test and [14]C-urea breath test as gold standard. Seventy six patients with dyspepsia were underwent [13]CUBT for diagnosis of Helicobacter pylori infection. Good agreements were found between the [13]C-UBT and gold standard methods. The [13]C-UBT showed 100% sensitivity, 97.3% specificity, 97.56% positive predictive value, 100% negative predictive value and 98.65% accuracy. On the basis of these results it could be concluded that [13]C-UBT performed with NDIR spectroscopy is a reliable, accurate and non invasive diagnostic tool for detection of Helicobacter pylori infection in the Iranian population

[Determination of radiation dose rates and urinary activity of patients received Sodium Iodide-131 for treatment of differentiated thyroid carcinoma]

Sodium Iodide-131 is administrated for treatment of hyperthyroidism and thyroid cancer. Iodine-131 has multiple routs of excretion [Urine, saliva, sweat, milk, feces, exhalation] from the body. Patients receiving Sodium Iodide-131 therapy exposes other persons and the environment to unwanted radiation and contamination. The major source of radiation dose from administration of Iodine-131 is external radiation, also there is a potential for exposure via contamination. Precautions are necessary to limit the radiation dose to family members, nursing staff and members of public and waste treatment workers to less than 1mSv. Patients received Sodium Iodide-131 may come into close contact with other persons. In order to derive appropriate recommendations, dose rates were measured from the anterior mid-trunk of 29 patients in the upright position within 15 minutes post-dose administration at 3 meters and just before they left the nuclear medicine department at 0.5, 1 and 3 meters. We have also measured urinary iodide excretion in 29 patients to estimate Sodium Iodide-131 urinary excretion pattern in Iranian patients. Based on results, the maximum cumulative dose to nursing staff was on third day [Leaving day] still less than recommended dose by ICRP. The cumulative dose of family members will be more but regarding the time and distance in close contact it will also be less than recommended dose by ICRP. Radiation dose rate was decreased significantly on third day. The urinary excretion patterns in all patients were similar. The urinary excretion rate-time curve in all patients showed multiple peaks due to retention and redistribution of Iodine-131 or entrohepatic cycle of radioiodinated thyroid hormones, which didn't allow calculation of urinary excretion rate constant. The results also showed that 67 hours post administration of Sodium Iodide-131 about 70% of radiopharmaceutical was excreted through urine, 28% physically decayed or eliminated through other biological routes