<Superscript>99m</Superscript>Tc-GSA SPECT/CT fusion imaging for hepatectomy candidates with extremely deteriorated ICG value

Purpose

The value of indocyanine green (ICG) test is negatively affected in patients with intrahepatic shunt, ICG excretory defect, or jaundice. This study evaluated ^99mTc-GSA SPECT/CT fusion imaging for assessing liver function in patients with severely deteriorated ICG values.

Materials and methods

Thirteen hepatectomy candidates with ICG retention rates over 40% were retrospectively analyzed. The ICG clearance rate (KICG) and estimated KICG obtained by ^99mTc-GSA scintigraphy (KGSA) were used to evaluate preoperative whole liver function. Remnant liver function was assessed using the remnant (rem) KICG (=?KICG?×?volumetric rate) and remKGSA (=?KGSA?×?functional rate) indices; hepatectomy was considered unsafe for values <?0.05. The correlations of remKICG and remKGSA with postoperative mortality and morbidity were also investigated.

Results

KGSA values were significantly greater than KICG values (median: 0.12 vs. 0.059; p?<?0.01); remKGSA values were greater than remKICG values in all patients (median: 0.107 vs. 0.0413; p?<?0.01). Hepatectomy was considered unsafe in 70% patients using remKICG, and in none of those using remKGSA; liver failure or postoperative mortality did not occur.

Conclusions

^99mTc-GSA SPECT/CT fusion imaging enables more accurate liver function assessment than the ICG test in patients with severely deteriorated ICG values.

     

<Superscript>99m</Superscript>Tc-GSA liver dynamic SPECT for the preoperative assessment of hepatectomy

OBJECTIVE: The purpose of the present study was to devise a predictive index to predict residual liver function before hepatic resection, using technetium-99m diethylenetriamine-penta-acetic acid-galactosyl human serum albumin (99mTc-GSA) liver dynamic single photon emission computed tomography (SPECT). METHODS: Fifty-seven patients with liver disease underwent liver dynamic SPECT with 99mTc-GSA. Dynamic SPECT was performed to obtain the k-value according to the accumulation curve after injection of 99mTc-GSA. The k-value is a mathematical reflection of the rate of disappearance of the circulating radiotracer as it is accumulated into the hepatocytes. We devised an original predictive residual index (PRI) by combining k-value with liver volume (V) and functional liver volume (FV). Correlation between these parameters and results of liver function tests and the grade of liver disease severity was analyzed. We investigated retrospectively the correlation between PRI and post-operative patient prognosis. RESULTS: The k-value slightly correlated with indocyanine green clearance test at 15 mins, bilirubin level and hepaplastin test. FV and V did not correlate with liver function tests. Post-operative complications were observed in 5 patients. The PRI of these patients was below 0.37. When PRI was above 0.38, no patient had hepatic failure. CONCLUSIONS: When PRI is above 0.38, there is a low probability of hepatic failure after hepatectomy. The PRI is useful in preoperative prediction of post-hepatectomy residual liver function in patients with liver disease.     

Molecular imaging in musculoskeletal infections with <Superscript>99m</Superscript>Tc-UBI 29-41 SPECT/CT

Objective

To determine the added value of CT over planar and SPECT-only imaging in the diagnosis of musculoskeletal infection using ^99mTc-UBI 29-4.

Materials and methods

184 patients with suspected musculoskeletal infection who underwent planar and SPECT/CT imaging with ^99mTc-UBI 29-41 were included. Planar, SPECT-only and SPECT/CT images were reviewed by two independent analysts for presence of bone or soft tissue infection. Final diagnosis was confirmed with tissue cultures, surgery/histology or clinical follow-up.

Results

^99mTc-UBI 29-41 was true positive in 105/184 patients and true negative in 65/184 patients. When differentiating between soft tissue and bone infection, planar?+?SPECT-only imaging had a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 95.0, 74.3, 84.8, 91.3 and 86.9%, respectively, versus 99.0, 94.5, 92.5, 98.5 and 94.5% for SPECT/CT. SPECT/CT resulted in a change in reviewers’ confidence in the final diagnosis in 91/184 patients. Inter-observer agreement was better with SPECT/CT compared with planar?+?SPECT imaging (kappa 0.87, 95% CI 0.71–0.85 versus kappa 0.81, 95% CI 0.58–0.75).

Conclusion

Addition of CT to planar and SPECT-only imaging led to an increase in diagnostic performance and an improvement in reviewers’ confidence and inter-observer agreement in differentiating bone from soft tissue infection.

     

Comparative Analysis of <Superscript>99m</Superscript>Tc-MDP Three-Phase Bone Scan with SPECT/CT and <Superscript>99m</Superscript>Tc-HMPAO-Labeled WBC SPECT/CT in the Differential Diagnosis of Clinically Suspicious Post-traumatic Osteomyelitis

Purpose

To identify differences between three-phase bone scan and SPECT/CT (TBS) and WBC SPECT/CT (WS) and compare diagnostic accuracies of each modality in patients with suspicious post-traumatic osteomyelitis (OM).

Methods

Twenty-one patients with suspicious post-traumatic OM were enrolled. All patients performed TBS and WS within 1 week. Foci of MDP and WBC accumulation were divided into three categories: bone (OM), soft tissue (soft tissue inflammation; STI), negative for inflammation (NI). Confirmative diagnosis was made upon operative pathology or long-term clinical follow-up.

Results

Of 21 patients, four OM, eight STI, nine NI were finally diagnosed. TBS diagnosis was correct in three of four positive cases and nine of 17 negative cases. Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV) of TBS were 75 %, 52.9 %, 57.1 %, 27.3 %, 90 %. WS diagnosis was correct in two of four positive cases and 17 of 17 negative cases. Sensitivity, specificity, accuracy, PPV, NPV were 50 %, 100 %, 81.0 %, 100 %, 89.5 %. Twelve of 21 cases showed agreement between TBS and WS. TBS misdiagnosed nine cases (six STI and two NI as eight OM; one OM as one STI), while WS misdiagnosed four cases (two OM as two STI; two STI as two NI). Combining results from TBS and WS led to better diagnostic accuracy (91.7 %) than either TBS or WS alone.

Conclusion

TBS and WS showed moderate agreement in assessment of clinically suspected post-traumatic OM. WS better evaluated inflammation than TBS. WS tended to underestimate inflammation whereas TBS tended to overestimate inflammation. Combining TBS and WS enhanced diagnostic accuracy.

     

<Superscript>18</Superscript>F-Fluorocholine PET/CT in the assessment of primary hyperparathyroidism compared with <Superscript>99m</Superscript>Tc-MIBI or <Superscript>99m</Superscript>Tc-tetrofosmin SPECT/CT: a prospective dual-centre study in 100 patients

Purpose

In this prospective study we compared the accuracy of ¹⁸F-fluorocholine PET/CT with that of ^99mTc-MIBI or^99mTc-tetrofosmin SPECT/CT in the preoperative detection of parathyroid adenoma in patients with primary hyperparathyroidism. We also assessed the value of semiquantitative parameters in differentiating between parathyroid hyperplasia and adenoma.

Methods

Both ¹⁸F-fluorocholine PET/CT and ^99mTc-MIBI/tetrofosmin SPECT/CT were performed in 100 consecutive patients with biochemical evidence of primary hyperparathyroidism. At least one abnormal focus on either ¹⁸F-fluorocholine or ^99mTc-MIBI/tetrofosmin corresponding to a parathyroid gland or ectopic parathyroid tissue was considered as a positive finding. In 76 patients with positive findings on at least one imaging modality, surgical exploration was performed within 6 months, and the results were related to histopathological findings and clinical and laboratory findings at 3–6 months as the standard of truth. In 24 patients, no surgery was performed: in 18 patients with positive imaging findings surgery was refused or considered risky, and in 6 patients imaging was negative. Therefore, data from 82 patients (76 undergoing surgery, 6 without surgery) in whom the standard of truth criteria were met, were used in the final analysis.

Results

All patients showed biochemical evidence of primary hyperparathyroidism with a mean serum calcium level of 2.78?±?0.34 mmol/l and parathormone (PTH) level of 196.5?±?236.4 pg/ml. The study results in 76 patients with verified histopathology and 3 patients with negative imaging findings were analysed. Three of six patients with negative imaging showed normalized serum PTH and calcium levels on laboratory follow-up at 3 and 6 months, and the results were considered true negative. In a patient-based analysis, the detection rate with ¹⁸F-fluorocholine PET/CT was 93% (76/82), but was only 61% (50/82) with ^99mTc-MIBI/tetrofosmin SPECT/CT. In a lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of ¹⁸F-fluorocholine PET/CT in the detection of parathyroid adenoma were 93.7%, 96.0%, 90.2%, 97.4% and 95.3%, respectively, and of ^99mTc-MIBI/tetrofosmin SPECT/CT were 60.8%, 98.5%, 94.1%, 86.3% and 87.7%, respectively. Although ¹⁸F-fluorocholine PET-positive adenomatous lesions showed higher SUVmax values than the hyperplastic glands (6.80?±?3.78 vs. 4.53?±?0.40) in the semiquantitative analysis, the difference was not significant (p?=?0.236). The mean size (measured as the length of the greatest dimension) and weight of adenomas were 15.9?±?7.6 mm (median 15 mm, range 1–40 mm) and 1.71?±?1.86 g (median 1 g, range: 0.25–9 g), respectively. Among the analysed parameters including serum calcium and PTH and the size and weight of parathyroid adenomas, size was significantly different between patients with negative ^99mTc-MIBI/tetrofosmin SPECT/CT and those with positive ^99mTc-MIBI/tetrofosmin SPECT/CT (mean size 13.4?±?7.6 mm vs. 16.9?±?7.4 mm, respectively; p?=?0.042).

Conclusion

In this prospective study, ¹⁸F-fluorocholine PET/CT showed promise as a functional imaging modality, being clearly superior to ^99mTc-MIBI/tetrofosmin SPECT/CT, especially in the detection and localization of small parathyroid adenomas in patients with primary hyperparathyroidism. SUVmax was higher in parathyroid adenomas than in hyperplasia. However, further evaluation of this modality is needed.

     

Use of quantitative SPECT/CT reconstruction in <Superscript>99m</Superscript>Tc-sestamibi imaging of patients with renal masses

Objective

Technetium-99m (^99mTc)-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has previously been shown to allow for the accurate differentiation of benign renal oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs) apart from other malignant renal tumor histologies, with oncocytomas/HOCTs showing high uptake and renal cell carcinoma (RCC) showing low uptake based on uptake ratios from non-quantitative single-photon emission computed tomography (SPECT) reconstructions. However, in this study, several tumors fell close to the uptake ratio cutoff, likely due to limitations in conventional SPECT/CT reconstruction methods. We hypothesized that application of quantitative SPECT/CT (QSPECT) reconstruction methods developed by our group would provide more robust separation of hot and cold lesions, serving as an imaging framework on which quantitative biomarkers can be validated for evaluation of renal masses with ^99mTc-sestamibi.

Methods

Single-photon emission computed tomography data were reconstructed using the clinical Flash 3D reconstruction and QSPECT methods. Two blinded readers then characterized each tumor as hot or cold. Semi-quantitative uptake ratios were calculated by dividing lesion activity by background renal activity for both Flash 3D and QSPECT reconstructions.

Results

The difference between median (mean) hot and cold tumor uptake ratios measured 0.655 (0.73) with the QSPECT method and 0.624 (0.67) with the conventional method, resulting in increased separation between hot and cold tumors. Sub-analysis of 7 lesions near the separation point showed a higher absolute difference (0.16) between QPSECT and Flash 3D mean uptake ratios compared to the remaining lesions.

Conclusions

Our finding of improved separation between uptake ratios of hot and cold lesions using QSPECT reconstruction lays the foundation for additional quantitative SPECT techniques such as SPECT-UV in the setting of renal ^99mTc-sestamibi and other SPECT/CT exams. With robust quantitative image reconstruction and biomarker analysis, there may be an expanded role for SPECT/CT imaging in renal masses and other pathologic conditions.

     

Single-photon agents for tumor imaging:<Superscript>201</Superscript>TI,<Superscript>99m</Superscript>Tc-MIBI,and<Superscript>99m</Superscript>Tc-tetrofosmin

This review aims at fostering comprehension and knowledge not only for expert physicians who can skillfully handle various techniques for tumor imaging but also for young practitioners in the field of nuclear medicine. As image processing software and hardware become smaller, faster and better, SPECT will adapt and incorporate these advances. A principal advantage of SPECT over PET is the more widespread availability of the equipment and lower cost for the introduction of the system in community-based facilities. Moreover, SPECT has become less dependent on a limited number of acknowledged experts for its interpretation owing to a variety of handy computer tools for imaging analyses. The increasing use of PET in tumor imaging is not necessarily proportional to the decline of SPECT. General physicians' attention to SPECT technology would also increase more by evoking their interest in "tracer imaging."     

<Superscript>99m</Superscript>Tc-ECD brain perfusion SPECT in hyperalgesic fibromyalgia

Purpose Neuro-imaging studies with ^99mTc-HMPAO SPECT in fibromyalgia (FM) patients have reported only limited subcortical hypoperfusion. ^99mTc-ECD SPECT is known to provide better evaluation of areas of high cerebral blood flow and regional metabolic rate. We evaluated a homogeneous group of hyperalgesic patients with FM using ^99mTc-ECD SPECT. The aim of this study was to investigate brain processing associated with spontaneous pain in FM patients. Methods Eighteen hyperalgesic FM women (mean age 49 years, range 25–63 years; American College of Rheumatology criteria) and ten healthy women matched for age were enrolled in the study. A voxel-by-voxel group analysis was performed using SPM2 (p<0.05, corrected for multiple comparisons). Visual Analogue Scale score for pain was 82±4 at the time of the SPECT study. Results Compared with control subjects, we observed individual brain SPECT abnormalities in FM patients, confirmed by SPM2 analysis, with hyperperfusion of the somatosensory cortex and hypoperfusion of the frontal, cingulate, medial temporal and cerebellar cortices. Conclusion In the present study, performed without noxious stimuli in hyperalgesic FM patients, we found significant hyperperfusion in regions of the brain known to be involved in the sensory dimension of pain processing and significant hypoperfusion in areas assumed to be associated with the affective-attentional dimension. As current pharmacological and non-pharmacological therapies act differently on the two components of pain, we hypothesise that SPECT could be a valuable and readily available tool to guide individual therapeutic strategy and provide objective follow-up of pain processing recovery under treatment.     

Clinical application of <Superscript>99m</Superscript>Tc-HYNIC-TOC SPECT/CT in diagnosing and monitoring of pancreatic neuroendocrine neoplasms

Objective

Our aim of this research was to determine the value of SPECT/CT with ^99mTc-HYNIC-TOC for evaluation of the pancreatic masses which were suspected as neuroendocrine neoplasms and follow-up of patients with pancreatic neuroendocrine neoplasms.

Methods

We retrospectively analyzed 184 patients who performed ^99mTc-HYNIC-TOC SPECT/CT. All the patients were divided into two groups: one for assessment of diagnostic efficiency for pancreatic suspected masses (n?=?140) and another for monitoring recurrence after surgery (n?=?44). The image findings acquired at 2 h postinjection were compared to final diagnoses from pathological results and clinical follow-up. Then, the correlation between ratios of tumor-to-background (TBR) and tumor grade was analyzed.

Results

In group 1, 95/140 (67.9%) patients were confirmed as neuroendocrine neoplasms including 85 neuroendocrine tumors and 10 neuroendocrine carcinomas. Patient-based analysis showed that the sensitivity, specificity and accuracy of diagnosing neuroendocrine neoplasms with SPECT/CT were 81.1, 84.4 and 82.1%. There was significant difference of TBRs among G1, G2 and G3 (F?=?3.175, P?=?0.048). In group 2, 22/44 (50.0%) patients occurred metastasis mainly in liver. The sensitivity, specificity and accuracy of monitoring recurrence were 87.0, 100 and 93.2%.

Conclusions

^99mTc-HYNIC-TOC SPECT/CT is a reliable method of diagnosing and monitoring of pancreatic neuroendocrine neoplasms, especially neuroendocrine tumors.

     

Relationship between <Superscript>99m</Superscript>Tc-GSA scintigraphic indices of liver function reserve and portal circulation in patients with chronic liver disease

Objectives In order to predict the prognosis or complications of portal hypertension in patients with chronic liver disease, it is important to evaluate both hepatic functional reserve and portal circulation. On ^99mTc-galactosyl human serum albumin (^99mTc-GSA) scintigraphy, the index of blood clearance (HH15) and receptor index (LHL15) have been widely used to evaluate the hepatic functional reserve. However, the relationship between these indices and portal circulation is unknown. The purpose of this study was to examine the relationship between HH15 and LHL15 and portosystemic shunts evaluated with arteriographic portography or esophagogastroduodenoscopy. Methods A total of 82 patients with chronic liver disease (mean age, 66.7 years) who underwent ^99mTc-GSA scintigraphy, arteriographic portography, and esophagogastroduodenoscopy were enrolled. HH15 and LHL15 were obtained from dynamic ^99mTc-GSA scintigraphy. The patients were divided into three groups according to the arteriographic portography findings: group 1, no portal collateral circulation; group 2, mild collateral development; and group 3, moderate to severe collateral development. They were also divided into three groups based on the esophagogastroduodenoscopic findings: group A, no varices; group B, small-caliber varices; and group C, enlarged varices. The Kruskal–Wallis test was used to compare each index among these groups. Receiver operating characteristic (ROC) analysis was used to determine whether each index was an indicator for the presence of portosystemic shunts. Results Both HH15 and LHL15 differed significantly between groups 1 and 2 and between groups 1 and 3. However, only HH15 differed significantly between groups A and B and between groups A and C. On the basis of the ROC analysis, the HH15 threshold value of 0.62 yielded both excellent sensitivity (83.9%) and specificity (84.6%) for the presence of portosystemic shunts, as evaluated with arteriographic portography. The HH15 threshold value of 0.64 yielded both good sensitivity (66.1%) and specificity (69.2%) for the presence of portosystemic shunts, as evaluated with esophagogastroduodenoscopy, whereas no adequate threshold value of LHL15 was found for the presence of portosystemic shunts. Conclusions HH15 is a potent indicator of the presence of portosystemic shunts in chronic liver disease.     

Questionnaire survey of hospitals in Saitama Prefecture regarding the shortage of <Superscript>99m</Superscript>Tc-labeled radiopharmaceuticals and <Superscript>99</Superscript>Mo/<Superscript>99m</Superscript>Tc generators

Objective and methods  

A questionnaire survey was conducted at all 32 hospitals in Saitama Prefecture to investigate the current difficult situation in terms of nuclear medicine management in the face of the ^99mTc shortage due to insufficient supply, and 29 hospitals (90.6%) replied.     

<Superscript>99m</Superscript>Tc-MAA/<Superscript>90</Superscript>Y-Bremsstrahlung SPECT/CT after simultaneous Tc-MAA/<Superscript>90</Superscript>Y-microsphere injection for immediate treatment monitoring and further therapy planning for radioembolization

Purpose  

An angiographic evaluation combined with ^99mTc-macroaggregated albumin (Tc-MAA) scanning should precede the treatment of any selected candidates for radioembolization (RE) of the liver. If the tumours in one liver lobe have not been targeted in the test angiogram, it should be repeated. However, in a few cases treatment of one liver lobe or at least some segments is safe and feasible and performing a repeated test angiogram with Tc-MAA (Re-MAA) in a separate session leads to more radiation exposure and could be time consuming. Our aim was to evaluate the feasibility of concurrent RE of a part of the liver and therapy planning for another region by simultaneous injection of the Tc-MAA and ⁹⁰Y-microspheres in two different locations in the therapy session. Tc-MAA and bremsstrahlung (BS) single photon emission computed tomography (SPECT)/CT were performed separately in an effort to distinguish between the distributions of these two different radiopharmaceuticals.     

Usefulness of SPECT/CT in Parathyroid Lesion Detection in Patients with Thyroid Parenchymal <Superscript>99m</Superscript>Tc-Sestamibi Retention

Purpose

Parathyroid adenoma detection with dual-phase ^99mTc-sestamibi (MIBI) scintigraphy depends on differential MIBI washout from thyroid. However, autoimmune thyroid disease (AITD) may cause MIBI to be retained in the thyroid gland and reduce parathyroid detection. We evaluated the impact of AITD on MIBI thyroid retention and additional benefit of SPECT/CT in these patients.

Methods

Dual phase planar MIBI and SPECT/CT was performed on 82 patients. SPECT/CT was performed immediately after delayed planar scan. Thyroid density (Hounsfield unit, CT-HU) and size were measured on CT component of SPECT/CT. MIBI uptake in early scans and retention in delayed scans were visually graded and correlated with clinical factors and CT findings. Finally, planar and SPECT/CT findings were compared for parathyroid lesion visualization according to thyroid MIBI retention.

Results

In early scan, multivariate analysis showed only thyroid size predicted early uptake. In delayed scan, multivariate analysis showed higher visual grade in early scan, lower CT-HU or AITD were significant predictors for delayed thyroid parenchymal retention. Overall, ten more parathyroid lesions were visualized on SPECT/CT compared to planar scans (57 vs. 47, p?=?0.002). SPECT/CT was especially more useful in patients with thyroidal MIBI retention, as eight out of the ten additional lesions detected were found in patients with thyroid MIBI retention.

Conclusion

AITD is an important factor for MIBI thyroid parenchymal retention on delayed scans, and may impede parathyroid lesion detection. Patients with MIBI retention in the thyroid parenchyma on delayed scans are likely to benefit from an additional SPECT/CT.

     

Evaluation of <Superscript>99m</Superscript>Tc-labeled antibiotics for infection detection

One of the fields of research in nuclear medicine is the development of new radiopharmaceuticals for imaging infection and inflammation in humans. For this development, several antimicrobial peptides, antibiotics, antibiotic peptide and chemotactic peptides, etc., have been radiolabeled with different radionuclides (⁶⁷Ga, ^99mTc, ¹¹¹In, ¹⁸F, ¹³¹I, etc.) and their imaging potentials studied. Actually, it is very important to distinguish between infection and inflammation. In this respect, radiolabeled antibiotics have advantages because many of the properties of the ideal infection-specific agent through antibiotics localizes in infection site. In this review, only ^99mTc-labeled antibiotics are evaluated and discussed.     

<Superscript>11</Superscript>C-methionine uptake in cerebrovascular disease: A comparison with<Superscript>18</Superscript>F-FDG PET and<Superscript>99m</Superscript>Tc-HMPAO SPECT

OBJECTIVES: Carbon-11-L-methyl-methionine (11C-methionine) has been reported to be useful for evaluating brain tumors, but several other brain disorders have also shown signs of high methionine uptake. We retrospectively evaluated the significance of 11C-methionine uptake in cerebrovascular diseases, and also compared our results with those for 18F-FDG PET and 99mTc-HMPAO SPECT. METHODS: Seven patients, including 3 patients with a cerebral hematoma and 4 patients with a cerebral infarction, were examined. All 7 patients underwent both 11C-methionine PET and 99mTc-HMPAO SPECT, and 6 of them underwent 18F-FDG PET. RESULTS: A high 11C-methionine uptake was observed in all 3 patients with cerebral hematoma. Increased 99mTc-HMPAO uptake was observed in 2 out of 3 patients, and all 3 patients had decreased 18F-FDG uptake. Of 4 patients with a cerebral infarction, high 11C-methionine uptake was observed in 3. Increased 99mTc-HMPAO uptake was also observed in one patient, whereas 3 patients had decreased 18F-FDG uptake. CONCLUSIONS: We should keep in mind that high 11C-methionine uptake is frequently observed in cerebrovascular diseases. CVD should therefore be included in the differential diagnosis when encounting patients with a high 11C-methionine uptake.     

Brown adipose tissue: Evaluation with<Superscript>201</Superscript>Tl and<Superscript>99m</Superscript>Tc-sestamibi dual-tracer SPECT

Brown adipose tissue is one kind of adipose tissue and regulates body temperature and balance of energy via non-shivering thermogenesis. The authors present a case that strongly suggested the presence of activated brown adipose tissue in the neck, shoulders and axillary space by increased 18F-FDG uptake. 99mTc-sestamibi and 201Tl dual-tracer SPECT study showed increased 99mTc-sestamibi uptake and non-increased 201Tl uptake in the corresponding 18F-FDG uptake sites. Brown adipose tissue has dense mitochondria in the cells, which play an important role in thermogenesis. 99mTc-sestamibi uptake and retention depend on the mitochondrial activity but 201Tl uptake does not. Therefore, the activity of mitochondria in activated brown adipose tissue may explain the discrepant uptake between 99mTc-sestamibi and 201Tl.     

Kinetic characterization of a novel cationic <Superscript>99m</Superscript>Tc(I)-tricarbonyl complex, <Superscript>99m</Superscript>Tc-15C5-PNP,for myocardial perfusion imaging

Background  

Intense liver uptake of ^99mTc-sestamibi (MIBI) often interferes with visualization of myocardial perfusion in the inferior wall of the left ventricle. To develop improved myocardial perfusion agents, crown ether-containing dithiocarbamates and bisphosphines have been introduced in recent years. This study was designed to investigate the myocardial imaging properties and in vivo kinetics of a cationic ^99mTc(I)-tricarbonyl complex, ^99mTc-15C5-PNP, in comparison with MIBI.