alireza emami ardekani

  To compare the diagnostic performance of [68Ga]-Ga-FAPI-46 and [18F]-FDG PET/CT imaging for the detection of lesions and disease staging in breast cancer.

Twelve female patients with breast cancer (mean age= 49.2±13.29 years) and previous [18F]-FDG PET/CT were recruited in the study. [68Ga]Ga-FAPI-46 imaging performed in all patients within one month after [18F]-FDG PET/CT imaging. The acquired PET/CT data with both tracers were reconstructed. Tracer avid lesions with each PET tracer were identified and the semi-quantitative parameters i.e. SUVmax, lesion counts and target-to-background ratio (TBRmax) were analyzed.

Physiologic distribution of [68Ga]-Ga-FAPI-46 was observed in the liver, blood pool and kidneys, whereas no tracer uptake was noted in the brain and heart. The mean liver SUVmax for [68Ga] Ga-FAPI-46 was 1.5±0.1 which was lower than that noted for [18F]-FDG PET/CT (2.9±0.2). Likewise, the mean blood pool SUVmax value for [68Ga]-Ga-FAPI-46 was lower than [18F]-FDG PET/CT (1.7±0.1 versus 2.0±0.1). [68Ga]-Ga-FAPI-46 PET/CT demonstrated higher tracer uptake in the lesions detected in the brain, bone, internal mammary and lymph nodes in 4/12 patients. The overall lesions detections and the mean SUVmax values did not differ significantly between the two techniques. On the other hand, [68Ga]-Ga-FAPI-46 demonstrated higher mean TBRmax than [18F] FDG PET/CT particularly for lesions detected in kidneys, chest wall, mediastinum, and musculoskeletal lesions. However, both techniques offered identical TNM staging.

The findings of this preliminary study demonstrated that [68Ga]-Ga-FAPI-46 and [18F]-FDG PET/CT offered identical disease staging in the breast cancer patients. [68Ga]-Ga-FAPI-46 showed lower liver and blood pool uptake and an enhanced tumor-to-background ratio, thereby suggesting its potential for improved lesions detection. This may open opportunity for emerging FAP based radioligand for therapeutic applications in advanced stage breast cancers. However, this needs validation in a larger number of patients.

Large Vessel Vasculitis (LVV) is a chronic inflammatory process that affects the aorta and its main branches. LVV include Takayasu’s Arteritis (TA) and Giant Cell Arteritis (GCA). The diagnosis of TA is made according to clinical criteria and based on the criteria of the American College of Rheumatology (ACR). Monitoring of disease progression and response to treatment is also done using the National Institutes of Health (NIH) criteria. Despite these criteria, diagnosing and evaluating TA activity is a challenging issue and usually occurs in the advanced stages of the disease. The lack of a comprehensive and non-invasive diagnostic method for diagnosing and monitoring the course of TA is obvious. The aim of this study was to evaluate the diagnostic agreement between 2-[18F]FDG PET-CT scan and clinical criteria for assessing TA disease activity. 

Twenty-four known cases of TA, who met the inclusion criteria, were enrolled in this study. The disease-related constitutional signs and symptoms, as well as laboratory and imaging findings were recorded. Patients underwent 2-[18F]FDG PET-CT imaging with standard protocol. Fused PET-CT images were reviewed and, if necessary, images without attenuation correction were visualized as well. Also, 24 control patients of the same age and sex, among the patients who were referred to the imaging center for oncological indications were examined to compare the uptake of different vascular territories.

Out of 15 active patients (according to the NIH criteria), 2-[18F]FDG PET-CT scan was able to correctly identify 14 patients. Also, out of 9 inactive patients, PET scan was negative in eight patients showing that 2-[18F]FDG PET-CT scan could well differentiate between active and inactive status of the disease (p-value < 0.0001). Sensitivity, specificity, positive predictive value and negative predictive value of scan in this study were 93.3%, 88.9%, 93.3% and 88.9%, respectively. The study also showed that the severity of vascular lesion uptake was not affected by immunosuppressive drugs, including corticosteroids and methotrexate. Scan findings were comparable with the results of anatomical imaging in terms of disease activity and the number of vascular lesions with p-value = 0.1 and 0.304, respectively.

In this study we showed that 2-[18F]FDG PET-CT has comparable results with other imaging modalities and NIH criteria; therefore, it can play an important role in assessing the severity of TA, even when patients are on immunosuppressive drugs.

Thyroid cancer is the most common endocrine malignancy in the world; however, these patients usually experience a high survival rate if they receive appropriate and timely treatment. Meanwhile, patients classified as having differentiated thyroid cancer with high thyroglobulin and negative iodine scan [Differentiated thyroid cancer with thyroglobulin elevation and negative iodine scintigraphy (TENIS)] are always considered a diagnostic-therapeutic challenge.

We conducted a comprehensive literature search of published papers in the PubMed/MEDLINE database regarding nuclear imaging in differentiated thyroid cancer with thyroglobulin elevation and negative iodine scintigraphy. We included all human studies in this field.

In this review, we examined four major groups of imaging studies aimed at identifying GLUT, SSTR, PSMA and FAP receptors in patients with TENIS. The diagnostic rate of 2-[18F]FDG PET/CT in these patients has been reported as 63-81% based on various studies. Also, [68Ga]Ga-DOTATATE PET/CT, [68Ga]Ga-PSMA PET/CT and [68Ga]Ga-FAPI PET/CT scans have shown good results in these patients.

[68Ga]Ga-FAPI PET/CT imaging has the highest diagnostic rate among these patients. Given the theranostic capability of FAPI and the numerous complications and limited inclusion criteria for treatment with tyrosine kinase inhibitors, it has been the next step in the treatment of patients with TENIS. Therefore, more extensive studies in this field are warranted.

2-[18F]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (2-[18F]FDG-PET/CT) is implemented in papillary thyroid cancer (PTC) patients with elevated Thyroglobulin (Tg) and negative Iodine-131 whole-body scan (131I-WBS). Here, we evaluated the impact of TSH stimulation after levothyroxine withdrawal on the detection rate of 2-[18F]FDG-PET/CT. A prospective study was performed on 60 PTC patients, presented with negative 131I-WBS and elevated or unjustifiably high Tg. 2-[18F]FDG-PET/CT was performed in 30 patients while they were on levothyroxine therapy (unstimulated-TSH [uns-TSH]) and after Levothyroxine withdrawal in the other 30 patients (stimulated-TSH [s-TSH]). Results of the two groups were compared using nonparametric tests. Receiver operating characteristic curve was used to find Tg cutoff values for predicting positive scan results. Overall, 2-[18F]FDG-PET/CT was positive in 63.3% of the patients, 80% (24/30) in s-TSH and 46.7% (14/30) in uns-TSH group. The detection rate was higher in s-TSH group (p=0.007). It was still significant in multiple regression analysis (p=0.041). In uns-TSH group, 2-[18F]FDG-PET/CT was more often positive in patients with higher uns-Tg level (p=0.002). An uns-Tg level of ≥19.00 ng/mL predicted positive results with the sensitivity of 0.786 and specificity of 0.750 (area under curve=0.819). Although statistically insignificant (p=0.055), s-Tg was higher in patients with positive 2-[18F]FDG-PET/CT studies in the s-TSH group. No relation was demonstrated between TSH and anti-Tg-antibody levels and 2-[18F]FDG-PET/CT positivity. TSH-stimulation after levothyroxine withdrawal might enhance the detection rate of 2-[18F]FDG-PET/CT in PTC patients. Additionally, 2-[18F]FDG-PET/CT is more often positive in patients with higher Tg levels.

Non-cutaneous malignant melanomas (NCM) are rare malignancies. Due to their nonspecific symptoms, they present later in life. The value of FDG PET/CT in this group of patients is not clear. The aim of this study is to assess the role of FDG PET/CT in the management of NCM and its prognostic implication.

We retrospectively selected twenty-three patients with a diagnosis of NCM evaluated with FDG PET/CT in Shariati hospital between 2019 and 2021. The PET/CT data were reviewed and compared with available conventional imaging findings. Five patients died within five months. The surviving patients were followed within a time interval of 7 to 27.5 months after their PET/CT study, regarding their disease status.

Among 23 patients (8 ocular, 5 sinonasal, 3 pharyngeal, 2 anorectal, 2 vulvovaginal, and 3 unknown primaries), PET/CT was able to detect residual primary disease, assess treatment response, and reveal or exclude metastases. Additional lesions compared to conventional imaging were found in five, while in one with brain metastases PET/CT was unable to detect lesions on MRI.  Thirteen patients had negative PET/CT finding of which 11 (85%) did not have remarkable finding on follow-up. Metastatic disease was recognized in eight. Patients with extensive metastases on FDG PET/CT had a poorer outcome.

Similar to cutaneous melanoma, PET/CT is valuable in the management of NCM patients and is superior to conventional imaging modalities, with the exception of brain metastases. Patients with negative PET/CT findings have a better outcome as opposed to patients with significant positive PET/CT findings.

Here, we describe a patient with a history of colorectal cancer in whom 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT) was performed for the evaluation of response to therapy. [18F]FDG PET/CT showed a small residual disease in the rectum. In addition, multiple metabolically inactive soft tissue densities were demonstrated in the left hemithorax and the left upper abdominal region, previously interpreted as metastases on computed tomography. Furthermore, bizarre-shaped soft tissues were visualized in the anatomical location of the spleen. Hence, splenosis was suspected. Subsequently, the patient underwent [99mTc]Tc-denatured red blood cell ([99mTc]Tc-DRBC) scintigraphy, which confirmed the diagnosis of extensive thoracoabdominal splenosis.

Adrenal lesions are commonly observed during 18F-FDG PET/CT studies. Although, most of these lesions are considered benign, an important consideration in oncologic patients is metastasis. Benign lesions, such as adenomas usually present with low 18F-FDG uptake, although overlap with malignant lesions exist and clear SUV cut-off for distinguishing adrenal adenomas has not been established. Different criteria have been proposed to further characterize adrenal lesions, as benign or metastatic. Conventional imaging modalities have additional value when the degree of uptake is equivocal. In this review, we go through some of the common adrenal lesions, as well as discerning features that favor either benign or malignant etiology.

Prostate-specific membrane antigen (PSMA) ligand positron emission tomography/computed tomography (PET/CT) is an emerging modality to detect metastatic disease in patients with prostate cancer (PCa). This prospective study aimed to evaluate the role of [68Ga]-PSMA PET/CT in the initial workup of intermediate and high-risk PCa . Twenty-five patients with newly transrectal ultrasound biopsy-proven, untreated intermediate- and high-risk PCa (mean age, 68.5±6.2 years; range 55–83 years) were enrolled in this prospective study between September 2018 and June 2020 and underwent a [68Ga]-PSMA PET/CT examination. All images were analyzed both visually and semiquantitatively by measuring the maximum standardized uptake value (SUVmax) of the primary prostatic tumor and metastatic lesions. The diagnostic sensitivity of [68Ga]-PSMA PET/CT for the diagnosis of PCa was established by histopathology as the reference standard. The associations between SUVmax of the primary tumors and prostate-specific antigen (PSA) levels, Gleason scores (GSs), and metastatic extent of the disease were studied. All patients had a positive [68Ga]-PSMA PET/CT exam. Seventeen patients (58%) showed [68Ga]-PSMA avidity in both prostate lobes and 8 (32%) had unilateral uptake. SUVmax in the primary tumor significantly correlated with serum PSA values (r=0.57, P=0.003). PSMA PET/CT depicted regional lymph node metastases in 32% of patients, distant lymph node metastases in 20%, osseous metastases in 16% and pulmonary metastases in 8% of patients. Sixty percent of PSMA-positive bone metastases and 21.4% of intraprostatic tumoral lesions were missed on the contemporaneous bone scintigraphy and magnetic resonance imaging, respectively. [68Ga]-PSMA PET/CT shows promise as a valuable imaging modality with high diagnostic sensitivity in the setting of intermediate and high-risk PCa. Moreover, the SUVmax of the primary tumor has a positive correlation with PSA levels at the time of the scan.

Rosai Dorfman disease is a rare form of nonlangerhans cell histiocytosis, presenting with extensive lymphadenopathies. Treatment in most cases of nodal disease, involves close observation; however, extranodal involvement requires a more definitive treatment strategy. Herein, we report a case of extensive Rosai Dorfman disease in a 43-year-old woman presenting for evaluation of treatment response by 18F-FDG PET/CT after frequent relapses and disease progression. In addition to extensive lymphadenothapies in cervical, supraclavicular, superior mediastinum, axillary, abdominopelvic and inguinofemoral regions, the patient had metabolically active bone and subcutaneous lesions which were not previously recognized. Following this 18F-FDG PET/CT study, the patient management was changed to sirolimus and prednisolone. To choose the best treatment option for Rosai Dorfman patients, knowledge of the full extent of disease is important. Compared with conventional imaging, 18F-FDG PET/CT has the advantage of being a whole-body imaging modality and can recognize disease involvement prior to any anatomical changes.

Differentiatedthyroid carcinoma (DTC) constitute approximately 90% of all thyroid tumors with an overall excellent prognosis. However, there is a small group of patients with a more aggressive form of disease, usually associated with certain poor prognostic factors. Using our large database of patients with DTC, the current study aims at identifying some of these factors. 

This retrospective study was based on the registry of patients with non-medullary thyroid carcinoma. Data were collected on the clinical, laboratory, and outcome characteristics of 501 patients followed at our department.

On multivariate analysis, the following variables were predictive of persistent disease: less than total thyroidectomy, residual disease on the post treatment whole body radioiodine scan (WBIS), higher received radioiodine activities, and higher levels of baseline stimulated thyroglobulin (Tg) and thyroid stimulating hormone (TSH). The greatest predictive value for the persistent/recurrent disease was attributed to the presence of residual disease on the post-treatment WBIS (odds ratio (OR): 33.72, 95% confidence interval (95% CI): 18.17-62.57), followed by type of surgical procedure (OR: 8.92, 95% CI: 2.90-27.39), radioiodine ablation dose (OR: 4.03, 95% CI: 1.56-10.39), stimulated baseline Tg level (OR: 2.79, 95% CI: 1.53-5.08) and finally, the stimulated baseline TSH level (OR: 2.21, 95% CI: 1.08-4.519).

In patients with DTCs, surgical procedures other than total thyroidectomy, presence of residual disease on the post-treatment WBIS, higher received radioiodine activities, higher baseline stimulated Tg and TSH levels are associated with a higher probability of having persistent disease and can be used in conjunction with other disease characteristics to reach proper decisions with regard to treatment and follow-up.

Multiple myeloma (MM) is a clonal B-lymphocyte neoplasm of terminally differentiated plasma cells. Imaging modalities which allow the recognition of the effects of myeloma cells on the skeletal system have been utilized for a long time. Herein, we represent a patient with generalized osteoporosis and hypercalcemia, who was referred for parathyroid scan, in whom the widespread bone marrow technetium-99m-methoxy-2-isobutylisonitrile (99mTc-MIBI) uptake suggested the presence of a bone marrow involving pathology, which turned out to be multiple myeloma on bone marrow biopsy. The current case report highlights the importance of 99mTc-MIBI scintigraphy, with a relatively low cost and better accessibility compared with other high sensitivity modalities such as PET-CT, to be used to demonstrate multiple myeloma bone marrow involvement, which could incline physicians to consider 99mTc-MIBI scintigraphy as a complementary diagnostic tool for multiple myeloma.

68Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) has shown promising results in imaging of neural crest tumors (NCT). Herein, we compared the performance of 68Ga-DOTATATE PET/CT and 131I-MIBG single photon emission computed tomography (SPECT)/CT in the initial diagnosis, staging and follow-up of patients with NCTs.

Twenty-five patients (males:females=8:17; age range=2–71 years) with clinically proven or suspicious neuroblastoma, pheochromocytoma (PCC) or paraganglioma (PGL) were enrolled in this prospective study and underwent both 68Ga-DOTATATE PET/CT and 131I-MIBG SPECT/CT. A composite reference standard derived from histopathological information, together with anatomical and functional imaging findings, was used to validate the results. Imaging findings were assessed on a per-patient and on a per-lesion basis. Sensitivity and accuracy were assessed using McNemar’s test.

Referring to radiological imaging and histopathological findings as reference standard, 68Ga-DOTATATE and 131I-MIBG scans showed a sensitivity and accuracy of (100%, 96%) and (86.7%, 88%), respectively, on a per-patient basis. In PCC/PGL patients, on a per-patient basis, the sensitivity of 68Ga-DOTATATE was 100% and that of 131I-MIBG was 77.8%. In neuroblastoma patients, on a per-patient basis, the sensitivities of both 68Ga-DOTATATE and 131I-MIBG were 100%. Overall, in this patient cohort, 68Ga-DOTATATE PET/CT identified 52 lesions and 131I-MIBG SPECT/CT identified only 30 lesions. On a per-lesion analysis, 68Ga-DOTATATE was found to be superior to 131I-MIBG in detecting lesions in all anatomical locations, particularly osseous lesions. According to the McNemar test results, differences were not statistically significant.

This relatively small patient cohort suggests 68Ga-DOTATATE PET/CT be superior to 131I-MIBG SPECT/CT in providing particularly valuable information for both primary staging and follow-up in patients with NCT.

Myocardial perfusion imaging (MPI) is an important imaging modality in managing patients with cardiovascular disease. MPI has a significant role in diagnosis and management of cardiovascular disease; however it is subjected to different artifacts. Combining pharmacologic stress with submaximal exercise reduces side effects, improves image quality, and enhances the detection of ischemia, compared with suboptimal exercise or vasodilator stress alone.
97 patients (62 males and 35 females) which were randomly allocated into two groups were studied using gated single-photon emission computed tomography (SPECT) imaging. The patients were randomly allocated into two different groups: dipyridamole or dipyridamole combined with submaximal exercise group. Subsequently, they were imaged at 15, 60, 120, and 180 minutes after radiotracer injection.
97 patients with an average age of 57.1 were compared 15, 60, 120 and 180 minutes after radiotracer injection. Comparing dipyridamole and dipyridamole submaximal exercise group a significant difference in target areas (myocardium, inferior and lateral wall) count ratio to both liver and colon count ratio was observed (P A protocol that combines submaximal exercise with dipyridamole stress is highly effective in improvingthe average count ratio of myocardial walls compared to visceral activity.

The present study was aimed to assess the diagnostic performance of the two imaging methods of 131I-metaiodobenzylguanidine (131I-MIBG) and 99mTc-hydrazinonicotinyl-Tyr3-Octreotide (99mTc-HYNIC-TOC) in diagnosis and localization of pheochromocytoma and neuroblastoma.
This study was conducted on 40 consecutive patients with positive pathological results for pheochromocytoma or neuroblastoma. The patients underwent both I-131 131I-MIBG and octreotide scintigraphies. By using the findings of cytopathology, biomarkers, imaging studies, as well as the results of a six-month follow-up, a composite reference standard (CRS) was defined as the diagnostic gold standard.
Overall comparison of these two agents revealed higher sensitivity for 131I-MIBG than octreotide study both in patient-based analysis (100% vs. 80.9%, respectively), and lesion-based analysis (94.4% vs. 80.56%, respectively). In pheochromocytoma 131I-MIBG and octreotide are both highly sensitive (100%), while 131I-MIBG is more specific (100% vs. 87.5%). In neuroblastoma, 131I-MIBG is more sensitive than octreotide (100% vs. 81.25%).
Our study shows superiority of 131I-MIBG over octreotide scanning in detection of both neuroblastoma and pheochromocytoma lesions. However, a combination of these two diagnostic tools provides more complete information on the nature and the site of lesions. The first suggested study is 131I-MIBG scanning, and if it is not available, or detecting precise location of all lesions is of concern, octreotide scanning can be helpful as a complementary study. Furthermore, in case of octreotide positive lesions, follow-up can be performed with octreotide scan with less radiation burden.

In an ideal parallel-hole collimator, thickness of septal material should be sufficient to stop more than 95% of incident photons. However, some photons pass the septa without interaction or experience scattering before they reach the detector. In this study, we determined different contribution of collimator responses consist of geometrical response, septal penetration (SP) and scattering (SC) for low, medium and high energy collimators.
A point source of activity with common energies in diagnostic nuclear medicine and three different collimators were simulated using SIMIND Monte Carlo code.
For Low Energy High Resolution (LEHR) collimator, SP was increased from 7% in 140 keV to 30% in 167keV and more than 75% in energies higher than 296keV. SC also was increased from 4% in 98keV to more than 15% in energies higher than 167keV and reached to its maximum (26%) in 296keV. For Medium Energy All Purpose (MEAP) collimator, SP was suddenly increased from 6% in 186keV to 28% for 296keV and more than 50% for higher energies. SC was also increased from 4% in energies below 186keV to 15% in 296keV and about 30% for higher energies. For High Energy (HE) collimator, SP was about 20% for 364keV photons. SC was 15% for 364keV photons and only 65% of photons were geometrically collimated.
Our results showed that even by using nominally suitable collimators, there are considerable SC and SP that influence the quantitative accuracy of planar and SPECT images. The magnitude of geometrical response, SC and SP depend on collimator geometric structure and photons energy.

Because of the increasing prevalence of both ischemic heart diseases and vitamin D deficiency and also due to recent evidences on association between these two phenomena, it is vital to clarify the association of ischemic heart disease with vitamin D deficiency and low bone mass.
The aim of the present study was to assess the relationship between low serum vitamin D and low bone mass measured by dual-energy X-ray absorptiometry (DEXA) with ischemic heart disease assessed by the functional radionuclide myocardial perfusion imaging (MPI).
Patients and In this cross-sectional study, 204 consecutive patients aged older than 50 years who were candidates for MPI were included. Blood sample was extracted to measure the level of serum 25-OH vitamin D using a special kit (IDS kit). Then, the patients were assessed by MPI. Within a month of myocardial perfusion scanning, subjects underwent bone mineral density (BMD) measurements by DEXA method.
There was no significant difference in serum level of vitamin D between patients with normal and those with abnormal MPI results. In addition, no significant correlation was detected between BMD and myocardial ischemia.
Coronary atherosclerosis may not be associated with the severity of low bone mass or level of vitamin D adequacy.

High-dose radioactive iodine therapy in differentiated thyroid cancer (DTC) may adversely affect the salivary gland function. This study is aimed to evaluate the effect of radioactive iodine (RAI) with dose of 100 mCi in DTC patients compared to lower doses of less than 30 mCi in hyperthyroid cases. Fifty four patients (13 men and 41 women) age: 42.3±14.3 (21-71) years were enrolled in the study. Twenty seven hyperthyroid cases received less than 30 mCi of I-131 for the treatment, and 27 DTC patients were treated with 100 mCi of I-131. All patients underwent Tc-99m pertechnetate scintigraphy before and three months after radioiodine therapy. Salivary gland excretion fractions (EF) were compared between groups. A decrease of more than 5% in EF was considered significant. The total frequency of salivary dysfunction was 41.7%. In patients received a dosage of 100 mCi of I-131, this frequency was 49.1%, while with less than 30 mCi, it was 34.3% (p<0.01). The right parotid gland was affected more than the left following 100 mCi treatment. Risk ratio of salivary gland involvement in high-dose versus low-dose group was significant (risk ratio=1.04-1.98, CI (95%); p=0.019). However, there was no significant difference in symptom presentation, i.e. xerostomia between two groups. RAI therapy may cause salivary gland dysfunction and this effect is more frequent in DTC patients with higher dose of 100 mCi compared to hyperthyroid cases with lower doses of less than 30 mCi.

Asymptomatic diabetic patients are at increased risk of cardiovascular complications. Myocardial perfusion scan may be effective in risk evaluation in this population. 106 asymptomatic diabetic patients (age: min: 37, max: 82, mean: 57.73±8.88), including 56 females (52.8%) and 50 males (47.2%) were enrolled in the study. Myocardial perfusion scintigraphy was performed by Gated Single Photon Emission Computed Tomography (Gated-SPECT) method. Perfusion and function status was evaluated by qualitative and semi-quantitative parameters. By visual analysis totally 40 out of 106 patients (37.7%) showed abnormal scan. From which, 26(24.5%) showed involvement in one, 13(12.3%) in two, and 1(0.9%) in all three vessel territories. By semi-quantitative method, from 103 patients, 28 (27.2%) were abnormal and 75 (72.8%) were normal. From all the asymptomatic diabetic patients, 11 patients (10.4%) had dilated left ventricles. Transient Ischemic Dilation (TID) was noted in 10 patients (9.4%), and Transient Right ventricle visualization in 7 patients (6.6%). Heart failure (EF<45%) was observed in 14% of asymptomatic diabetic patients. From underlying factors, long duration of diabetes disease correlated to abnormal myocardial perfusion imaging (MPI) findings (Odds Ratio: 2.77; CI: 1.07-7.12). Severe coronary artery disease leading to the pattern of severe ischemia or infarction in MPI, was significantly higher in men than women (P=0.05). Also smoking correlated with higher involvement of LAD coronary artery (P=0.011) and as compared with RCA territory (P=0.079). In asymptomatic diabetic patients myocardial perfusion scintigraphy can be used in early diagnosis of coronary artery disease (CAD) and can be suggested as screening study in these patients.

Bone metastases are the most common cause of cancer-related pain in various primary malignant tumors, most often, breast and prostate. 188Re-hydroxyethylidene diphosphonate (188Re-HEDP) is a new and less expensive bone seeking radiopharmaceutical with favorable physical characteristics of the radionuclide such as short half life of 16.9h, maximal β energy of 2.1 MeV with a 15% γ-component of 155 keV and easily available from an in-house 188W/188Re generator. The aim of this study is to evaluate the therapeutic efficacy and safety profile of bone palliative therapy following administration of 188Re-HEDP. Twenty patients with painful metastatic bone lesions secondary to breast, prostate, multiple myeloma, ampulla of vater and lung cancers received 1 mCi/kg of 188Re-HEDP. Four hours after treatment, post-therapy scintigraphy was performed. All patients were interviewed using a standard set of questions (visual analogue scale: VAS) concerning their pain relief before, and after therapy at weekly intervals for the first month and every 2 weeks for the following 4 months. The general condition of the patients was also evaluated by Karnofsky-index and ECOG (Eastern Cooperative Oncology Group) performance status. Hematologic profiles were recorded before treatment and every two weeks up to 8 weeks after treatment. Overall pain relief was found in 68.8% of patients. Decreased from 8.37±2.12 to 5.68±2.98 at VAS was observed 4 weeks after treatment. The osteoblastic lesions (breast and prostate) showed rather similar response to the treatment. Mean platelet counts decreased in 6th week and returned to baseline level in 8th week. One patient showed grade III leukopenia without any serious complication. 188Re-HEDP is an effective radiopharmaceutical for metastatic bone pain palliation therapy. Side effects include mild and transient thrombocytopenia and leucopenia and no life threatening side effect is observed.

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.

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 99mTc-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.

Monte Carlo (MC) is the most common method for simulating virtual SPECT projections. It is useful for optimizing procedures, evaluating correction algorithms and more recently image reconstruction as a forward projector in iterative algorithms; however, the main drawback of MC is its long run time. We introduced a model based method considering the effect of body attenuation and imaging system response for fast creation of noise free SPECT projections. Collimator detector response (CDR) was modeled by layer by layer blurring of activity phantom using suitable Gaussian functions. Using the attenuation phantom, in each angle, attenuation factor (AF) was calculated for each voxel. This calculated AF is the weight for the emission voxel and states the detection probability of photons that are emitted from that voxel. Finally weighted ray sum of the blurred phantom was driven to create a projection. For the next projection, our phantom was rotated and the procedure was repeated until all projections were acquired. Root Mean Square error (RMS) between all 60 modelled projection and real MC simulated projections was decreased from 0.58 ± 0.15 using simple Radon to 0.19 ± 0.03 using our suggested model. This value was 0.56 ± 0.16 using blurred Radon without attenuation modelling, and 0.21 ± 0.03 using attenuated Radon without CDR modelling. Our suggested model that considers the effect of both attenuation and CDR simultaneously results in more accurate analytical projections compared with conventional Radon model. Creation of 60 primary SPECT projections in less than one minute may make this method as a proper alternative for MC simulation. This model can be used as a forward projector during iterative image reconstruction for correction of CDR and attenuation that is necessary for quantitative SPECT.

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 99mTc-UBI scan was performed for all the patients. 555-740 MBq of 99mTc-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 99mTc-UBI, all had positive bacterial cultures. The result of bone scan was positive for osteomyelitis in 12 patients (80%). 99mTc-UBI Scintigraphy was positive in 6 patients, but negative in nine. The sensitivity of 99mTc-UBI for detection of infection was therefore 40%. From 12 patients who had positive bone scans, only 6 had a positive 99mTc-UBI (50%) indicating the sensitivity of 50% for 99mTc-UBI in osteomyelitis cases. 99mTc-UBI was not positive in any patient who had evidence of soft tissue infection in the bone scan. Although 99mTc-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.

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.