Notable Visualization of the Gallbladder on a 99mTc-MDP SPECT/CT Bone Scintigraphy in a Case of Brucellosis.

Comprehension of the typical distribution pattern of 99mTc-methylenediphosphonate (MDP) is crucial for precise interpretation of bone scintigraphy. The presence of nonskeletal activity is predominantly confined to the kidneys and bladder, attributed to the standard renal excretion of 99mTc-MDP. We discuss a 70-year-old woman with a known case of brucellosis using rifampin, doxycycline, trimethoprim/sulfamethoxazole (co-trimoxazole), and ciprofloxacin for the past 8 months. Anterior and posterior aspects of the whole-body bone scan showed diffuse increased uptake in the bodies of L2 and L3 vertebrae and related intervertebral disks. However, unexpected uptake is noted in the right upper quadrant in the region of the gallbladder. Radiochemical impurities did not show during radiopharmaceutical (MDP) quality control, and the other patients showed normal distribution. This gallbladder uptake may be attributed to the altered distribution of the radiotracer and/or gallbladder injury caused by the administration of antibiotic therapy.

QCard-NM: Developing a semiautomatic segmentation method for quantitative analysis of the right ventricle in non-gated myocardial perfusion SPECT imaging.

BACKGROUND: Recent studies have shown that the right ventricular (RV) quantitative analysis in myocardial perfusion imaging (MPI) SPECT can be beneficial in the diagnosis of many cardiopulmonary diseases. This study proposes a new algorithm for right ventricular 3D segmentation and quantification. METHODS: The proposed Quantitative Cardiac analysis in Nuclear Medicine imaging (QCard-NM) algorithm provides RV myocardial surface estimation and creates myocardial contour using an iterative 3D model fitting method. The founded contour is then used for quantitative RV analysis. The proposed method was assessed using various patient datasets and digital phantoms. First, the physician's manually drawn contours were compared to the QCard-NM RV segmentation using the Dice similarity coefficient (DSC). Second, using repeated MPI scans, the QCard-NM's repeatability was evaluated and compared with the QPS (quantitative perfusion SPECT) algorithm. Third, the bias of the calculated RV cavity volume was analyzed using 31 digital phantoms using the QCard-NM and QPS algorithms. Fourth, the ability of QCard-NM analysis to diagnose coronary artery diseases was assessed in 60 patients referred for both MPI and coronary angiography. RESULTS: The average DSC value was 0.83 in the first dataset. In the second dataset, the coefficient of repeatability of the calculated RV volume between two repeated scans was 13.57 and 43.41 ml for the QCard-NM and QPS, respectively. In the phantom study, the mean absolute percentage errors for the calculated cavity volume were 22.6% and 42.2% for the QCard-NM and QPS, respectively. RV quantitative analysis using QCard-NM in detecting patients with severe left coronary system stenosis and/or three-vessel diseases achieved a fair performance with the area under the ROC curve of 0.77. CONCLUSION: A novel model-based iterative method for RV segmentation task in non-gated MPI SPECT is proposed. The precision, accuracy, and consistency of the proposed method are demonstrated by various validation techniques. We believe this preliminary study could lead to developing a framework for improving the diagnosis of cardiopulmonary diseases using RV quantitative analysis in MPI SPECT.

Toward applying a device to reduce motion artifact during imaging: a randomized controlled trial.

OBJECTIVE: One of the most critical problems in different types of medical imaging modalities is unwanted patient movement during imaging procedures, which mainly occurs because of stress, anxiety, and restlessness in patients, resulting in poor image quality and decreased diagnostic accuracy. METHODS: This prospective, randomized, double-blinded, controlled trial comprised 267 patients who underwent MPI, randomly divided into three groups; Group I: streaming music with a special binaural beat frequency (MBB); Group II: streaming simple music (SM) and Group III: control group. Anxiety level was determined by the Depression Anxiety Stress-Scale (DASS) questionnaire and heart rate was monitored. RESULTS: Stress and anxiety scores were significantly lower in the MBB group compared with both SM and control group (P˂0.0001). Additionally, a significant decrease in heart rate of patients who were in the MBB group in comparison with the SM (p = 0.005) and control group (P = 0.018) was observed. The study revealed a significant decrease in motion artifact in the MBB group compared with the SM (P = 0.003) and control (P˂0.0001) groups. CONCLUSIONS: Using the proposed device capable of streaming special binaural beat frequency embedded music can cause a significant reduction in anxiety level, heart rate, and consequently motion artifact.

The effect of chewing-gum on dose rate of salivary gland in differentiated thyroid carcinoma patients treated with radioiodine.

BACKGROUND: Although, different methods have been suggested on reducing salivary gland radiation after radioiodine administration, an effective preventive or therapeutic measure is still debated. To the best of our knowledge this is the second study that aimed to evaluate the effect of chewing-gum as a sialagogue on the radioiodine content of salivary gland, and radioiodine-induced symptoms of salivary gland dysfunction. METHODS: Twenty-two patients who were referred to radioiodine therapy were randomized into chewing-gum (group A) and control (group B) groups. Anterior and posterior planar images including both head and neck were obtained 2, 6, 12, 24 and 48 hours after the administration of radioiodine in all patients and round regions of interest (ROI) were drawn for both left and right parotid glands with a rectangular ROI in the region of cerebrum as the background. All patients were followed once, 6 months after radioiodine administration via a phone call for subjective evaluation of symptoms related to salivary gland damage. RESULTS: There was no significant difference between the two groups regarding the mean age, gender and initial iodine activity. The geometric mean of background-corrected count per administrated dose and acquisition time was calculated for bilateral parotid glands. This normalized parotid count showed a significant reduction in net parotid count in both groups during the first 48 hours after the radioiodine administration. However, no significant difference was found between the groups according to the amount and pattern of dose reduction in this time period. CONCLUSIONS: This study revealed that chewing-gum had no significant effect on the radioiodine content of parotid glands during the first 48 hours after radioiodine administration. Also, no significant difference was found in the incidence of relevant symptoms after 6 months comparing both groups.

Effects of the attenuation correction and reconstruction method parameters on conventional cardiac dynamic SPECT.

Nuclear cardiology has not witnessed development of new tracers or hardware for many years. Hence there is a need for the development of improvised techniques. Dynamic cardiac single photon emission computed tomography (SPECT) is one such technique that has a potential to overcome the limitations of conventional myocardial SPECT including the absolute quantification of blood flow. The main goal of this study is to evaluate the effect of attenuation correction (AC) on estimation of the washout parameters extracted from dynamic SPECT using a conventional protocol. The effect of the postprocessing on quantitative evaluation of dynamic SPECT is also assessed.A physical phantom was employed to physically simulate the dynamic behavior of a heart in the thorax. Using a dual detector SPECT system, 180° tomographic data in every 90 seconds were acquired. The SPECT data were reconstructed using ordered subset expectation maximization (OSEM) method while different iterations and a Butterworth filter with different cut-off frequencies were applied. Estimated washout parameter of the time activity curves (TACs) was compared with applying AC or without it.Results show that AC can improve the bias of computed washout parameter in normal regions (average bias reduction in normal ROI: 7%). Moreover, the postreconstruction filtering and reducing the number of iterations in reconstructing phase can reduce the variance of the computed washout values in normal regions (from 3.99% for cut-off frequency 0.5 cycle/cm and 32 times update in OSEM to 2.05% for cut-off frequency 0.35 cycle/cm and 16 times update in OSEM). They also reduce the actual size of the defect region (13% reduction in defect extent for above change in reconstruction parameters).According to the results, the AC and postprocessing filtration can directly affect the standard deviation of washout value acquired by cardiac dynamic SPECT. These parameters also showed a direct effect on the defect extent in final results. The study showed that the AC may partly improve the bias of calculated normal washout value. The effect of attenuation correction on the defective washout value could not be answered comprehensively in this paper.

Adrenocortical adenoma manifesting as false-positive iodine accumulation in a patient with history of thyroid carcinoma.

A 47-year-old female diagnosed with well-differentiated papillary thyroid carcinoma was referred to our center for a 131Iodine whole body scintigraphy as follow-up. The patient had been previously treated with total thyroidectomy and ablative dose of 175mCi 131I three years ago. Diagnostic 131I scan showed a zone of radioiodine uptake in posterior aspect of the left upper quadrant of the abdomen. Spiral abdominal and pelvic CT scan showed an enhancing solid mass in superior aspect of the left adrenal gland, which was in favor of metastasis to the lymph node or an adrenal tumor. A biopsy was performed from the lesion. Histological examination of the surgical specimen was consistent with adrenocortical adenoma. Even though rare, adrenocortical adenoma should be included in the potential causes of false-positive results of radioiodine scans.

Role of Hepatobiliary Scintigraphy in the Diagnosis of Gallbladder Agenesis; A Case Report and Brief Review of Literature.

Gallbladder agenesis (GA) is a rare congenital anomaly. Only 50% of the cases with GA are symptomatic, presenting mostly in the 4th or 5th decade of life. The clinical presentation of GA and imaging findings are non-specific and often misinterpreted as other diseases such as ectopic gall bladder. This can lead to unnecessary surgery when the final diagnosis is usually made. Although GA can cause an identical pattern to acute cholecystitis in hepatobiliary scintigraphy, in certain clinical settings, scintigraphy can be helpful as a confirmatory study, especially to rule out the possibility of ectopic gall bladder. In our case, the combination of imaging findings including ultrasonography, computed tomography, and hepatobiliary scintigraphy led to accurate diagnosis avoiding further surgeries.

Pilocarpine effect on dose rate of salivary gland in differentiated thyroid carcinoma patients treated with radioiodine.

OBJECTIVE: Although different methods have been suggested on reducing salivary gland radiation after radioiodine administration, an effective preventive or therapeutic measure is still up for debate. The aim of this study was to evaluate the effect of pilocarpine, as a sialagogue drug on the radioiodine content of the salivary gland, and radioiodine-induced symptoms of salivary gland dysfunction. PATIENTS AND METHODS: Patients who were referred for radioiodine therapy were randomized into pilocarpine and placebo groups. The patients as well as the nurse who administered the tablets, and the specialist who analyzed the images, were all unaware of the patients' group. Anterior and posterior planar images including that of both the head and neck were obtained 2, 6, 12, 24, and 48 h after the administration of radioiodine in all patients, and round regions of interest were drawn for both left and right parotid glands, with a rectangular region of interest in the region of the cerebrum as background. All patients were interrogated once, 6 months after radioiodine administration, by a phone call for subjective evaluation of symptoms related to salivary gland damage. RESULTS: There was no significant difference between the two groups with regard to the mean age, sex, and initial iodine activity. The geometric mean of background-corrected count per administered dose and acquisition time was calculated for the bilateral parotid glands. This normalized parotid count showed a significant reduction in net parotid count in both groups during the first 48 h after radioiodine administration. However, no significant difference was found between the groups according to the amount and pattern of dose reduction in this time period. CONCLUSION: This study revealed that pilocarpine had no significant effect on the radioiodine content of parotid glands during the first 48 h after radioiodine administration. No significant difference was found in the incidence of symptoms between the two groups treated with placebo and pilocarpine.

Impact of the Amount of Liquid Intake on the Dose Rate of Patients Treated with Radioiodine.

PURPOSE: Despite therapeutic effects of radioiodine in patients with differentiated thyroid cancer, there are some disadvantages due to harmful radiation to other tissues. According to the current guidelines, patients are recommended to drink lots of water and frequent voiding to reduce the amount of 131I in the body. This study was designed to assess the impact of the amount of liquid intake on reduction of the measured dose rate of radioiodine-treated patients. MATERIALS AND METHODS: A total of 42 patients with differentiated thyroid cancer without metastasis who had undergone total thyroidectomy and had been treated with radioiodine were selected. The patients were divided into two groups according to the amount of their fluid intake which was measured during the first 48 h after 131I administration. In all patients, the dose rate was measured immediately and 48 h after iodine administration. RESULTS: Each group included 21 patients. Dose rate ratio (the ratio of the second dose rate to the first dose rate) and dose rate difference ratio (the ratio of the difference between the two measured dose rates to the first dose rate) were calculated for each patient. Despite the significant difference in the amount of the liquid drunk, no statistically significant difference was seen between the different groups in parameters of dose-rate ratio and dose-rate difference ratio. CONCLUSION: Higher fluid intake (>60 ml/h in our study) alone would not effectively reduce the patient's radiation dose rate at least not more than a well-hydrated state. It seems that other interfering factors in the thyroidectomized patients may also have some impacts on this physiologic process.

Assessment of the dose distribution of Minibeam radiotherapy for lung tumors in an anthropomorphic phantom: A feasibility study.

BACKGROUND: Microbeam radiotherapy (MRT) is a treatment in which radiation field is divided into several separate fields of 10-100 µm width and 100-400 µm spacing. In this treatment, normal tissue can tolerate high doses that are delivered to its small volumes. OBJECTIVE: MCNPX 2.4 Monte Carlo code was used to calculate the dose distribution of MRT in a lung tumor in a simulated Rando phantom. METHODS: The effects of tissue inhomogeneities, using contrast media and changing the number of beams were investigated. Dose volume histograms and beam profiles of target and organs at risk were assessed and the dose uniformity in the target region was evaluated using homogeneity. The conformity indices also used to quantify the conformation of the shape of prescribed isodose volume to the shape and size of the target. RESULTS: Tissue inhomogeneity of this region did not interfere significantly with target dose homogeneity. The use of contrast media or increasing the number of beams improved target dose homogeneity and decreased the dose to surrounding tissues. CONCLUSIONS: The results suggest that further investigation and evaluation of MRT for treatment of chest tumors is worthwhile.

Reverse perfusion pattern in myocardial perfusion imaging using technetium-99m-sestamibi in patients with intermediate risk for coronary artery disease in relation to the time of acquisition and intensity of visceral uptake as artifactual causes.

OBJECTIVE: With respect to the equivocal value of the reverse perfusion pattern (RPP) in technetium-99m (Tc)-sestamibi myocardial perfusion imaging, a study was carried out to evaluate this pattern in association with the presence or absence of coronary artery disease (CAD) and other underlying factors, mainly the time of acquisition and the presence of intense visceral uptake. PATIENTS AND METHODS: We prospectively studied 102 patients with a moderate risk of CAD (41 men and 61 women, mean age: 56.5±9.2 years) without a previous history of documented CAD, myocardial infarction, or revascularization. Myocardial perfusion imaging was performed using a 2-day dual-phase protocol with the stress and rest images, each obtained 15, 120, and 180 min after an injection of 666-814 MBq Tc-MIBI. According to the time of image acquisition, the following five protocols were defined, A: 15/15 min, B: 15/180 min, C: 180/180 min, D: 180/15 min, and E: 120/120 min for stress/rest images, respectively. RESULTS: The odds of RPP were higher in the cases with more intense infradiaphragmatic visceral uptake on rest-phase images of the protocols A and D (odds ratios=1.2-7.8 and 1.2-7.5, respectively). Our results showed that RPP is related to incorrect normalization. Also, diabetes, sex, and CAD did not correlate with RPP. CONCLUSION: This study found no relationship between RPP and CAD, diabetes mellitus, and sex; however, an association was found between RPP and incorrect normalization because of the variation of visceral uptake intensity in relation to the time of acquisition at stress and rest phases favoring the artifactual base of this pattern.

Impact of sweating on equivalent dose of patients treated with (131)Iiodine.

BACKGROUND: Radioiodine therapy is used for the treatment of patients with differentiated thyroid cancer (DTC) who undergo total thyroidectomy. After radioiodine administration, regulations require to quarantine these patients until their retained activity reduces to <33 mCi. Some of the injected radioiodine is excreted by perspiration which helps dose reduction so that performing the activities which stimulate sweating such as exercise may shorten the time of dose reduction. To the best of our knowledge, this is the first study in the literature that has evaluated the impact of specific exercise program on the ambient equivalent dose of (131)I gamma rays. MATERIALS AND METHODS: Patients with DTC without metastasis who had undergone total thyroidectomy and were treated with radioiodine were included in this study. 30 patients were chosen among patients who were able to exercise, did not have renal failure, and did not use diuretics. Patients were divided into two control and intervention groups. Intervention group members walked on treadmills under a specific program, in 3 time intervals. The control group did not have any specific activity. Immediately after each exercise process, both groups took a shower, and their doses were measured by a survey dosimeter. RESULTS: It was revealed that there was a significant difference between mean values before and after each exercise time. The calculated P value which evaluates the overall impact was 0.939 which revealed that there was no significant difference between total ambient equivalent dose reductions of both groups. CONCLUSION: According to the study, it may conclude that sweating is an effective alternative way for radioiodine excretion, and if sweating is accompanied with well-hydrated status they may have synergism effect to shorten quarantine period. This could be an important consideration in patients which over-hydration is intolerable especially those with cardiac, liver, or renal problems.

Calculation of Blood Dose in Patients Treated With 131I Using MIRD, Imaging, and Blood Sampling Methods.

Radioiodine therapy is known as the most effective treatment of differentiated thyroid carcinoma (DTC) to ablate remnant thyroid tissue after surgery. In patients with DTC treated with radioiodine, internal radiation dosimetry of radioiodine is useful for radiation risk assessment. The aim of this study is to describe a method to estimate the absorbed dose to the blood using medical internal radiation dosimetry methods. In this study, 23 patients with DTC with different administrated activities, 3.7, 4.62, and 5.55 GBq after thyroidectomy, were randomly selected. Blood dosimetry of treated patients was performed with external whole body counting using a dual-head gamma camera imaging device and also with blood sample activity measurements using a dose calibrator. Absorbed dose to the blood was measured at 2, 6, 12, 24, 48, and 96 hours after the administration of radioiodine with the 2 methods. Based on the results of whole body counting and blood sample activity dose rate measurements, 96 hours after administration of 3.7, 4.62, and 5.55 GBq of radioiodine, absorbed doses to patients' blood were 0.65 ±â€Š0.20, 0.67 ±â€Š0.18, 0.79 ±â€Š0.51 Gy, respectively. Increasing radioiodine activity from 3.7 to 5.55 GBq increased blood dose significantly, while there was no significant difference in blood dose between radioiodine dosages of 3.7 and 4.62 GBq. Our results revealed a significant correlation between the blood absorbed dose and blood sample activity and between the blood absorbed dose and whole body counts 24 to 48 hours after the administration of radioiodine.

Is Brown Adipose Tissue Visualization Reliable on 99mTc-Methoxyisobutylisonitrile Diagnostic SPECT Scintigraphy?

The 99mTc-MIBI has been used with great value as a diagnostic technique in patients with primary hyperparathyroidism. False-positive scans may occur due to misinterpretation of the physiologic distribution of the 99mTc-MIBI. Reviewing consecutive SPECT scans, we evaluated this possibility and assessed how frequently brown adipose tissue (BAT) is seen on 99mTc-MIBI scintigraphy. Here, we retrospectively reviewed scans of consecutive patients who were evaluated for parathyroid adenomas from March 2015 to June 2015, using dual-phase (early and delayed) planar imaging and SPECT. We identified 60 patients (48 female and 12 male; mean age, 52.25 ±â€Š15.20 years; range, 22-86 years).We detected the presence of 99mTc-MIBI uptake in BAT in 20 of 60 patients (33.33%) in the neck. Although the patients with T99mc-MIBI uptake in BAT were younger (mean age, 48.85 ±â€Š15.27 years, range, 26-73 years) than the patients with no 99mTc-MIBI uptake (mean age, 53.95 ±â€Š15.07 years, range, 22-86 years), this difference was not statistically significant (P = 0.224). The percentage of female patients with BAT detection was higher (17/48 patients; 37.5%) than that of the male population (3/12 patients; 25%), this difference was not also statistically significant (P = 0.85).In patient population referred to 99mTc MIBI scintigraphy of the parathyroid glands, uptake of 99mTc-MIBI in BAT should not be misinterpreted with 99mTc-MIBI-avid-tumors. Fused SPECT/CT images (not SPECT-only) are necessary to distinguish BAT from bone, muscle, thyroid, myocardium, parathyroids, and other structures in the neck and chest.

Hiatal hernia uptake of iodine-131 mimicking mediastinal metastasis of papillary thyroid carcinoma.

There are a few case reports of hiatal hernia demonstrating thoracic uptake on I-131 scintigraphy. In this case, high thyroglobulin levels in combination with misinterpretation of I-131 uptake in the mediastinum, leaded to mismanagement of the patient. Here we present a case of focal I-131 uptake within a hiatal hernia initially mimicking an isolated mediastinal metastasis. There are many potential causes of false-positive I-131 scan result. In this case, adjunctive chest computed tomography and gastroesophageal barium study helped to elucidate the true nature of this I-131 uptake. False-positive findings may be caused by a wide variety of nonthyroidal carcinomas, which can concentrate radioiodine or from skin contamination. Several organs, such as the gastric, salivary glands, renal cyst, pericardial effusion, and ovarian can accumulate I-131. It should be borne in mind as a potential source of false-positive whole-body I-131 imaging.

Importance of Heparin Provocation and SPECT/CT in Detecting Obscure Gastrointestinal Bleeding on 99mTc-RBC Scintigraphy: A Case Report.

We presented a pediatric case with a history of intermittent melena for 3 years because of angiodyplasia of small intestine. The results of frequent upper gastrointestinal endoscopies and colonoscopies as well as both Tc-red blood cell (RBC) and Meckel's scintigraphies for several times were negative in detection of bleeding site. However, Tc-RBC scintigraphy with single-photon emission computed tomography (SPECT)/computed tomography (CT) after heparin augmentation detected a site of bleeding in the distal ileum which later was confirmed during surgery with final diagnosis of angiodysplasia.It could be stated that heparin provocation of bleeding before Tc-RBC scintigraphy accompanied by fused SPECT/CT images should be kept in mind for management of intestinal bleeding especially in difficult cases.

Multiple Myeloma and Abdominal Aortic Aneurysm on Myocardial Perfusion Raw Images.

Reviewing cine display of planar projections just after data acquisition of myocardial perfusion imaging is helpful not only for checking quality of the study but also for better interpretation of incidental findings by acquiring more helpful images. We present a patient with significant skeletal Tc-MIBI uptake accompanied by a large photopenic area in abdominal cavity in myocardial perfusion imaging raw images that were further confirmed as multiple myeloma and thrombotic abdominal aortic aneurysm, respectively.

Incidentally Visualization of the Thymus on Whole-Body Iodine Scintigraphy: Report of 2 Cases and Review of the Latest Insights.

Radioiodine uptake is not commonly seen by the thymus gland. On the contrary, the gland is slowly replaced by fat after puberty. Herein, we present 2 patients with papillary thyroid carcinoma, follicular variant, and cervical lymph node involvement. After total/near-total thyroidectomy, the patients received I for ablation therapy. On posttreatment radioiodine scintigraphy, mediastinal I uptake was noted that finally was histologically/anatomically diagnosed as thymus gland uptake. It should be borne in mind as a potential cause of false-positive whole-body I scintigraphy.

Comparative evaluation of the diagnostic accuracy of (99m)Tc-sestamibi gated SPECT using five different sets of image acquisitions at stress and rest phases for the diagnosis of coronary artery disease.

On the basis of some new evidences in favor of delayed (99m)Tc methoxy-isobutyl-isonitrile ((99m)Tc-MIBI) redistribution, doubts about the appropriate time of acquisition following radiotracer injection may be raised. The goal of this study was to find the best acquisition time at stress and rest phases to achieve the highest sensitivity and normalcy rate for (99m)Tc-MIBI SPECT. Ninety four patients with moderate pretest probability of coronary artery disease (CAD) according to "Framingham Risk Score" enrolled in the study. Myocardial perfusion imaging (MPI) with SPECT was performed on the basis of two-day protocol with stress- and rest-phase images obtained at 15, 60, 120 and 180 minutes after injection of 666-814 MBq (99m)Tc-MIBI. According to the time of image acquisition at stress/rest phases, five protocols were defined: A, 15/180 min, B, 15/15 min, C, 180/180 min, D, 180/15 min and E, 120/120 min for stress and rest images, respectively. The sensitivity of MPI for the diagnosis of angiographically proven CAD were 77.3%, 50%, 63.6%, 45.5%, 68.2% and normalcy rate were 72.1%, 72.1%, 75.5%, 70.6%, 92.6% in protocol A, B, C, D and E, respectively. A significant association between SSS and Gensini score was detected only with protocol A (p=0.038). The most sensitive and specific two-day protocols for MPI with (99m)Tc-MIBI were protocol A and E, respectively. In addition, the best relationship between scintigraphic score of ischemia and angiographic score of CAD was achieved using protocol A (i.e. early acquisition at stress phase and late acquisition at rest phase).