Utility of 99mTc-Sestamibi Heart/Liver Uptake Ratio in Screening Nonalcoholic Fatty Liver Disease During Myocardial Perfusion Imaging.

Purpose: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic hepatic disease worldwide, with functional impairment of the mitochondria occurring from early stages. Technetium-99m methoxy-isobutyl-isonitrile (99mTc-MIBI) is a lipophilic agent trapped in the mitochondria. This study aims to evaluate the utility of 99mTc-MIBI heart/liver uptake ratio in screening for NAFLD during myocardial perfusion imaging (MPI). Methods: Seventy eligible patients underwent a 2-d rest/stress 99mTc-MIBI scan with a 2-min planar image acquired in rest phase, at 30, 60, and 120 min postradiotracer administration. Heart/liver uptake ratio was calculated by placing identical regions of interest on the heart and liver dome. All patients underwent liver ultrasound and were allocated into groups A, having NAFLD; and B, healthy individuals without NAFLD. Results: Mean count per pixel heart/liver ratios gradually increased over time in either group; nonetheless the values were significantly higher in group A, regardless of acquisition timing; with the p-value equal to 0.007, 0.014, and 0.010 at 30, 60, and 120 min, respectively. Conclusion: Determining 99mTc-MIBI heart/liver uptake ratio during rest phase in patients undergoing MPI may be a useful, noninvasive screening method for NAFLD; with no additional cost, radiation burden, or adverse effects in these patients. Trial registration number: IR.SBMU.MSP.REC.1398.308.

An automatic segmentation framework for computer-assisted renal scintigraphy procedure.

One of the techniques for achieving unique and reliable information in medicine is renal scintigraphy. A key step for quantitative renal scintigraphy is segmentation of the kidneys. Here, an automatic segmentation framework was proposed for computer-aided renal scintigraphy procedures. To extract kidney boundary in dynamic renal scintigraphic images, a multi-step approach was proposed. This technique is featured with key steps, namely, localization and segmentation. At first, the ROI of each kidney was estimated using Otsu's thresholding, anatomical constraint, and integral projection, which is done in an automatic process. Afterwards, the ROI obtained for the kidneys was used as the initial contours to create the final counter of kidneys using geometric active contours. At this step and for the segmentation, an improved variational level set was utilized through Mumford-Shah formulation. Using e.cam gamma camera system (SIEMENS), 30 data sets were used to assess the proposed method. By comparing the manually outlined borders, the performance of the proposed method was shown. Different measures were used to examine the performance. It was found that the proposed segmentation method managed to extract the kidney boundary in renal scintigraphic images. The proposed technique achieved a sensitivity of 95.15% and a specificity of 95.33%. In addition, the section under the curve in the ROC analysis was equal to 0.974. The proposed technique successfully segmented the renal contour in dynamic renal scintigraphy. Using all the data sets, a correct segmentation of the kidney was performed. In addition, the technique was successful with noisy and low-resolution images and challenging cases with close interfering activities such as liver and spleen activities.

Comparison of Accuracy in Calculation of Absorbed Dose to the Kidneys Following Radioligand Therapy with 177Lu-DKFZ-PSMA-617 by Two Different Background Correction Methods.

Background: To improve the accuracy of activity image quality, scatter correction is a critical method. The aim of this study is to compare the accuracy in calculation of absorbed dose to patients following radioligand therapy (RLT) with 177Lu-DKFZ-PSMA-617 by two different methods of background correction in the conjugate view method. Materials and Methods: This study involved 10 patients. The individualized patient dosimetry calculations were based on whole-body planar scintigraphy images acquired in 10 patients with a mean age of 71.4 ± 6.07 years (range 63-85 years) at approximately 0-2 h, 4-6 h, 18-24 h, and 36-48 h after administration of the mean 6253 ± 826.4 MBq (range 5500-7400 MBq) of 177Lu-DKFZ-PSMA-617. Organ activities were calculated using the conjugate view method by Buijs and conventional background correction. Eventually, the absorbed dose of radiation was calculated using Medical Internal Radiation Dose formalism. Results: The dose per unit of injected activity (mGy/MBq) ± standard deviation for kidney using Buijs and conventional methods was 1.05 ± 0.11 and 0.63 ± 0.14, respectively. Conclusion: The Buijs background correction method was more accurate than the conventional method.

Radiation Dose to Medical Staff from Administering 177Lu-PSMA-DKFZ-617 Therapy.

The number of radioligand therapy applications for metastatic castration-resistant prostate cancer has been continuously rising in most nuclear medicine departments in Iran, but to our knowledge, no one has studied the dose to staff who perform treatment procedures. The current study aimed to determine the external radiation dose received by staff who, using or not using a lead shield, treat patients with 177Lu-prostate-specific membrane antigen therapy. Methods: This study used a personal thermoluminescent digital survey meter to measure dose rates to staff at various distances from patients and determined the average time spent by staff at these distances. The deep-dose equivalent to staff was obtained. Results: The measured deep-dose equivalent to staff per patient was within the range of 1.8-5.2 mSv using a 2-mm lead shield and 3.3-8.1 mSv not using the shield. The shield markedly reduced the external dose to staff. Conclusion: The skill and accuracy of staff, and the speed with which they act, can directly affect their received dose.

Patient-Specific Dosimetry in Radioligand Therapy (RLT) for Metastatic Prostate Cancer Using 177Lu-DKFZ-PSMA-617.

PURPOSE: 177Lu-DKFZ-PSMA-617 is a promising treatment for patients with metastatic prostate cancer. Specific dosimetry for each patient is an important factor in planning the patient's treatment process. This study aimed to perform an image-based absorbed dose calculation for the treatment of metastatic prostate cancer with 177Lu-DKFZ-PSMA-617. METHODS: The individualized patient dosimetry calculations were based on whole-body planar scintigraphy images acquired in 10 patients with a mean age of 71.4 ± 6.07 years (range 63-85 years) at approximately 0-2 h, 4-6 h, 18-24 h, and 36-48 h after administration of the mean 6253 ± 826.4 MBq (range 5500-7400 MBq) of 177Lu-DKFZ-PSMA-617. Time-activity curves were generated for various organs. For count conversion to activities, calibration factors were calculated. Finally, the absorbed dose for an individual cycle was calculated using IDIAC-DOSE 2.1 software. RESULTS: On average, the calculated absorbed dose for the kidneys and salivary glands were 0.46 ± 0.09 mGy/MBq and 0.62 ± 0.07 mGy/MBq, respectively. CONCLUSIONS: Based on the results, the177Lu-PSMA-617 therapy is a safe method for the treatment of castration-resistant prostate cancer patients. Large inter-individual variations in organ dose were found, demonstrating the need for patient-specific dosimetry and treatment planning.

Somatostatin-receptor avidity of pancreatic neuroendocrine tumor thrombus in porto-caval venous systems on 99mTc-Octreotide and posttherapeutic 177Lu-DOTA-TATE scans.

A 62-year-old woman with a history of abdominal pain presented with multiple hepatic lesions and dilatation of portal, splenic and superior mesenteric veins on the magnetic resonance imaging referred for a 99mTc-octreotide scan. Accordingly, similar octreotide-avid lesions were found as well as an uptake in the epigastric region conforming to the anatomy of the portocaval venous system, compatible with a tumor thrombosis. Then, the patient underwent two cycles of therapy with 177Lu-DOTA-TATE, on that the same appearance was observed. The uptake in the tumor thrombus remained somewhat unchanged, but clinically, a significant improvement of the intractable ascites was achieved.

Efficacy and safety of 177Lutetium-prostate-specific membrane antigen therapy in metastatic castration-resistant prostate cancer patients: First experience in West Asia - A prospective study.

Prostate-specific membrane antigen (PSMA) is a transmembrane protein that is highly expressed on the surface of prostate cancer (PC) cells, making it an excellent radiotracer for both therapeutic and diagnostic purposes. In this prospective study, we investigated the efficacy and toxicity of 177Lutetium (Lu)-PSMA in metastatic castration-resistant PC (mCRPC) patients for the establishment and approval of this therapy in Iran. Fourteen mCRPC patients (mean age 70.57 ± 7.3 years) were treated with a single dose of 177Lu-PSMA. Complete blood count, liver function tests (aspartate aminotransferase and alanine aminotransferase), alkaline phosphatase levels, renal function tests (urea and creatinine), and prostate-specific antigen (PSA) levels were obtained for the patients at baseline and every 2 weeks. A majority of the patients (11 patients, 64.2%) experienced a decline in their PSA levels; in 5 (45.4%) of these patients, the PSA levels declined > 50%.The severity of pain decreased in 8 (57.1%) patients, and performance status was improved in 5 (45.4%) patients. The treatment was well tolerated, and no severe hematological or nonhematological side effects were observed. Our findings show that 177Lu-PSMA had a high efficacy and a low toxicity in an Iranian population and is a promising treatment option for PC patients.

Evaluation of Prognostic Factors Associated With Differentiated Thyroid Carcinoma With Pulmonary Metastasis.

BACKGROUND: Because one of the major sites for metastasis of thyroid cancers is the lung, studying the pattern of pulmonary metastasis may provide useful information for the effective treatment of these patients. In this study, by assessing the metastasis pattern, we aimed to identify the factors that may affect prognosis and response to treatment in patients with differentiated thyroid carcinoma (DTC) with pulmonary metastasis. METHODS: This retrospective study included 75 patients with DTC with pulmonary metastasis who were referred to our nuclear medicine section over a period of 10 years. The data obtained were analyzed with regard to response to treatment to assess the effects of the included factors on prognosis. RESULTS: Of the 1746 patients referred to our section, 75 (4.3%) had pulmonary metastasis. According to the pattern of pulmonary metastasis, they were divided into 4 groups: nodular, diffuse, combined, and other. The mean age of the patients was 43.8 ± 18.5 years. After the follow-up, 58 patients survived, 14 of whom responded to the treatment. The mean number of radioiodine therapy sessions that the patients received was 3.2 ± 2, and the mean cumulative dose was 554.7 ± 387.8 mCi. Statistical analysis of the data revealed that there was no significant difference in the response to treatment between patients with different patterns of pulmonary metastasis (P > 0.3). However, significant differences were reported in the response to treatment between patients with papillary thyroid carcinoma and those with follicular thyroid carcinoma (P < 0.03). The 1-, 5-, and 9-year survival rates were reported as 98%, 76%, and 51%, respectively. CONCLUSIONS: Patients with DTC with pulmonary metastasis have a relatively favorable prognosis and response rate, as well as longer survival. The type of DTC is the only factor that affects the response to treatment.

Diagnostic Efficacy of UBI Scan in Musculoskeletal Infections.

BACKGROUND: Limited recent studies have demonstrated that 99mTc-UBI scan can be a helpful method in precise diagnosis of infection. In the current study, we aimed to investigate the diagnostic efficacy of 99mTc-UBI scan in detection of musculoskeletal infections. METHODS: Fifty patients with suspected musculoskeletal infections (painful THA, TKA, implant and nonunion) were enrolled in this study. After injection of 99mTc-Ubiquicidin 29-41, up to 30 minutes, dynamic imaging was performed every 1 minute. Whole body anterior and posterior images were acquired at 60 and 120 min (5 min/frame). A polygonal region of interest (ROI) was drawn manually around the area of increased accumulation of tracer (lesion) and anatomically similar area on the contralateral side (background) and the lesion to background ratio (LBR) was calculated. Then, patients underwent surgical procedures to assess infection by tissue sampling and histopathologic studies as gold standard. The receiver operating characteristics (ROC) analysis was performed to find a cut-off value for LBR and determining the diagnostic efficacy of UBI scan in musculoskeletal infections. RESULTS: Histopathologic studies revealed infection in 38 patients. The mean LBR was significantly higher in infected patients (2.05 ± 0.41 vs. 1.52 ± 0.22; P < 0.001). ROC analysis showed that a cut-off point of 1.74 for LBR will have 94.7% sensitivity, 83.3% specificity and 92% accuracy for diagnosis of musculoskeletal infections. CONCLUSION: UBI scan is a useful diagnostic tool for evaluation of patients with suspected musculoskeletal infection. However, UBI imaging has some limitations which result in some incorrect diagnoses. It is important to interpret the results of the scan with regard to the clinical findings.

Uptake Difference by Somatostatin Receptors in a Patient with Neuroendocrine Tumor: 99mTc-Octreotide Uptake in the Lung without Uptake in Liver Lesions.

The diagnostic value of somatostatin receptor scintigraphy (SRS) in detecting tumors has been assessed in a number of studies. We present a 30-year-old female with a history of eight months cough and left shoulder pain. Radiologic evaluation showed pulmonary mass and hepatic lesions, which were pathologically diagnosed as neuroendocrine carcinoma. 99mTc-octreotide scan demonstrated that the pulmonary lesion was positive for somatostatin receptor (SSTR), while the liver metastases were SSTR negative. The present case highlights the significance of a differential uptake pattern by somatostatin receptors in SRS in patients with neuroendocrine tumors.

Technical Considerations of Phosphorous-32 Bremsstrahlung SPECT Imaging after Radioembolization of Hepatic Tumors: A Clinical Assessment with a Review of Imaging Parameters.

Background. Bremsstrahlung (BS) imaging during radioembolization (RE) confirms the deposition of radiotracer in hepatic/extrahepatic tumors. The aim of this study is to demonstrate (32)P images and to optimize the imaging parameters. Materials and Methods. Thirty-nine patients with variable types of hepatic tumors, treated with the intra-arterial injection of (32)P, were included. All patients underwent BS SPECT imaging 24-72 h after tracer administration, using low energy high resolution (LEHR) (18 patients) or medium energy general purpose (MEGP) (21 patients) collimators. A grading scale from 1 to 4 was used to express the compatibility of the (32)P images with those obtained from CT/MRI. Results. Although the image quality obtained with the MEGP collimator was visually and quantitatively better than with the LEHR (76% concordance score versus 71%, resp.), there was no statistically significant difference between them. Conclusion. The MEGP collimator is the first choice for BS SPECT imaging. However, if the collimator change is time consuming (as in a busy center) or an MEGP collimator is not available, the LEHR collimator could be practical with acceptable images, especially in a SPECT study. In addition, BS imaging is a useful method to confirm the proper distribution of radiotherapeutic agents and has good correlation with anatomical findings.

Abnormal focal 99mTc-DMSA uptake in the lung--report of two cases.

Extrarenal uptake of 99mTc-DMSA is a rare finding, which has been described in some unusual conditions as bone metastasis, aortic aneurysm and hemangioma. The purpose of this report is to present two cases of abnormal 99mTc-DMSA uptake in the lungs, which remained unexplained even after radiologic assessment.

99mTc-octreotide uptake in the uterus and a subserosal myoma mimicking tumoral masses.

The diagnostic usefulness of somatostatin receptor scintigraphy in the localization of tumors has been evaluated in several studies. Here, we present the case of a patient with a subserosal myoma diagnosed by (99m)Tc-labeled octreotide acetate scintigraphy. Oval and ring-shaped areas of hyperactivity in the pelvis were confirmed on MR imaging to be the uterus and a subserosal myoma. The presented case indicates that somatostatin receptors may be present in the uterus and in leiomyomas, especially in young women, and demonstrates that somatostatin may be a promising therapy for treatment of myoma. The case also demonstrates that subserosal myoma or dislocation of the uterus can result in a false-positive diagnosis, highlighting the importance of correlative imaging for accurate interpretation of the study.

Phase 2 study of a high dose of 186Re-HEDP for bone pain palliation in patients with widespread skeletal metastases.

UNLABELLED: (186)Re-1-hydroxyethylidene-1,1-diphosphonate (HEDP) is an attractive radiopharmaceutical for the treatment of bone pain arising from skeletal metastatic lesions. Currently, (186)Re-HEDP is most commonly used in European countries. The aim of this study was to investigate the palliative efficacy and adverse effects of (186)Re-HEDP in patients with different types of cancers and skeletal bone pain. METHODS: Nineteen (8 male, 11 female) patients with various cancers (breast, prostate, renal cell carcinoma, colon, and neuroendocrine tumors) and painful bone metastases were included in the study. A dose of 1,480-3,330 MBq (40-90 mCi) of (186)Re-HEDP was administered intravenously. The patients' level of pain relief was assessed by the Visual Analog Scale for 8 wk after treatment and by a weekly blood cell count to evaluate for hematologic toxicity. RESULTS: The overall response rate was 89.5%, and the mean pain score assessed by the Visual Analog Scale was reduced from 9.1 to 5.3 after 1 wk (P = 0.003). No adverse effects were reported by patients during intravenous administration or for up to 24 h after administration. A flare reaction was seen in 63.2% of patients, mainly during days 1-3, and lasted for 2-4 d. There was no significant correlation between the response to therapy and the flare reactions (P > 0.05). The nadir of platelet reduction occurred at the fourth or fifth week and led to platelet infusion in only 4 patients with a low baseline platelet count and diffuse skeletal metastases. Bone marrow suppression occurred in patients receiving higher doses, but no clinical problems were seen except in 2 patients who required packed cell transfusion similar to their prior transfusions. CONCLUSION: (186)Re-HEDP is an effective radiopharmaceutical for the palliative treatment of metastatic bone pain and has minimal adverse effects.

Metastasis of femoral osteosarcoma to the abdominal wall detected on 99m Tc-MDP skeletal scintigraphy.

Osteosarcoma is the most frequent primary malignancy of bone, and usually metastasizes to the lung and bones, while other sites are rare. In most reported cases, soft tissue metastasis of osteosarcoma is unusual, and only develops in the advanced stages of the disease, especially following multiple recurrences. We present a patient with recently diagnosed osteosarcoma of the right femur, showing abdominal wall metastasis diagnosed by technetium-99m-methylene diphosphonate (99m Tc-MDP) whole body bone scintigraphy and confirmed histologically. The present case highlights the importance of whole body imaging of patients with osteosarcoma for detecting unusual sites of metastasis, especially in soft tissue organs.

Short-term effectiveness of radiochemoembolization for selected hepatic metastases with a combination protocol.

AIM: To introduce the combination method of radiochemoembolization for the treatment of selected hepatic metastases. METHODS: Twenty patients with biopsy proven hepatic metastases were selected from those who underwent transarterial radiochemoembolization, a novel combination protocol, between January 2009 and July 2010. Patients had different sources of liver metastasis. The treatment included transarterial administration of three chemotherapeutic drugs (mitomycin, doxorubicin and cisplatin), followed by embolization with large (50-150 µm) radioisotope particles of chromic 32P. Multiphasic computer tomography or computer tomography studies, with and without contrast medium injections, were performed for all patients for a short-term period before and after the treatment sessions. The short-term effectiveness of this procedure was evaluated by modified response evaluation criteria in solid tumors (mRECIST), which also takes necrosis into account. The subjective percentage of necrosis was also assessed. The response evaluation methods were based on the changes in size, number, and the enhancement patterns of the lesions between the pre- and post-treatment imaging studies. RESULTS: Patients had liver metastasis from colorectal carcinomas, breast cancer, lung cancer and carcinoid tumors. The response rate based on the mRECIST criteria was 5% for complete response, 60% for partial response, 10% for stable disease, and 25% for progressive disease. Regarding the subjective necrosis percentage, 5% of patients had complete response, 50% had partial response, 25% had stable disease, and 20% had progressive disease. Based on traditional RECIST criteria, 3 patients (15%) had partial response, 13 patients (65%) had stable disease, and 4 patients (20%) had disease progression. In most patients, colorectal carcinoma was the source of metastasis (13 patients). Based on the mRECIST criteria, 8 out of these 13 patients had partial responses, while one remained stable, and 5 showed progressive disease. We also had 5 cases of breast cancer metastasis which mostly remained stable (4 cases), with only one partial response after the procedure. Six patients had bilobar involvement; three of them received two courses of radiochemoembolization. The follow up imaging study of these patients was performed after the second session. In the studied patients there was no evidence of extrahepatic occurrence, including pulmonary radioactive deposition, which was proven by Bremsstrahlung scintigraphy performed after the treatment sessions. For the short-term follow-ups for the 2 mo after the therapy, no treatment related death was reported. The mostly common side effect was post-embolization syndrome, presented as vomiting, abdominal pain, and fever. Nineteen (95%) patients experienced this syndrome in different severities. Two patient had ascites (with pleural effusion in one patient) not related to hepatic failure. Moreover, no cases of acute liver failure, hepatic infarction, hepatic abscess, biliary necrosis, tumor rupture, surgical cholecystitis, or non-targeted gut embolization were reported. Systemic toxicities such as alopecia, marrow suppression, renal toxicity, or cardiac failure did not occur in our study group. CONCLUSION: Radiochemoembolization is safe and effective for selected hepatic metastases in a short-term follow-up. Further studies are required to show the long-term effects and possible complications of this approach.

Automatic left ventricle segmentation in volumetric SPECT data set by variational level set.

INTRODUCTION: Left ventricle (LV) quantification in nuclear medicine images is a challenging task for myocardial perfusion scintigraphy. A hybrid method for left ventricle myocardial border extraction in SPECT datasets was developed and tested to automate LV ventriculography. METHODS: Automatic segmentation of the LV in volumetric SPECT data was implemented using a variational level set algorithm. The method consists of two steps: (1) initialization and (2) segmentation. Initially, we estimate the initial closed curves in SPECT images using adaptive thresholding and morphological operations. Next, we employ the initial closed curves to estimate the final contour by variational level set. The performance of the proposed approach was evaluated by comparing manually obtained boundaries with automated segmentation contours in 10 SPECT data sets obtained from adult patients. Segmented images by proposed methods were visually compared with manually outlined contours and the performance was evaluated using ROC analysis. RESULTS: The proposed method and a traditional level set method were compared by computing the sensitivity and specificity of ventricular outlines as well as ROC analysis. The results show that the proposed method can effectively segment LV regions with a sensitivity and specificity of 88.9 and 96.8%, respectively. Experimental results demonstrate the effectiveness and reasonable robustness of the automatic method. CONCLUSION: A new variational level set technique was able to automatically trace the LV contour in cardiac SPECT data sets, based on the characteristics of the overall region of LV images. Smooth and accurate LV contours were extracted using this new method, reducing the influence of nearby interfering structures including a hypertrophied right ventricle, hepatic or intestinal activity, and pulmonary or intramammary activity.

Value of sentinel lymph node biopsy in breast cancer surgery with simple pathology facilities--an Iranian local experience with a review of potential causes of false negative results.

INTRODUCTION: Sentinel lymph node biopsy (SLNB) is a precise procedure for lymphatic staging in early breast cancer. In a valid SLNB procedure, axillary lymph node dissection (ALND) can be omitted in node- negative cases without compromising patient safety. In this study, detection rate, accuracy and false negative rate of SLNB for breast cancer was evaluated in a setting with simple modified conventional pathology facilities without any serial sectioning or immunohistochemistry. MATERIAL AND METHOD: Patients with confirmed breast cancer were enrolled in the study. SLNB and ALND were performed in all cases. Lymph node metastasis was evaluated in SLN and in nodes removed by ALND to determine the false negative rate. Pathologic assessment was carried out only by modified conventional technique with only 3 sections. Detection rate was determined either by lymphoscintigraphy or during surgery. RESULTS: 78 patients with 79 breast units were evaluated. SLN was detected in 75 of 79 cases (95%) in lymphoscintigraphy and 76 of 79 cases (96%) during surgery. SLN metastases was detected in 30 of 75 (40%) cases either in SLNB and ALND groups. Accuracy of SLNB method for detecting LN metastases was 92%. False negative rate was 3 of 30 of positive cases: 10%. In 7 of 10 cases with axillary lymphadenopathy, LN metastastates was detected. CONCLUSION: SLNB is recommended for patients with various tumor sizes without palpable lymph nodes. In modified conventional pathologic examination of SLNs, at least macrometastases and some micrometastases could be detected similar to ALND. Consequently, ALND could be omitted in node-negative cases with removal of all palpable LNs. We conclude that SLNB, as one of the most important developments in breast cancer surgery, could be expanded even in areas without sophisticated pathology facilities.