Intense and prolonged Tl-201 accumulation in a slow growing bronchioloalveolar carcinoma

Thallium-201 SPECT was performed to evaluate a pulmonary lesion in a 73-year-old male which had been considered to be an inflammatory lesion for two years. The lesion has slowly increased in size on x-CT. Tl-201 was intensely taken up and retained in the lesion, suggesting a malignant lesion. Histological examination revealed that the lesion was bronchioloalveolar carcinoma. This case suggested that Tl-201 uptake of pulmonary carcinoma would not be necessarily related to cell growth rate.     

Comparative biodistribution of indium- and yttrium-labeled B3 monoclonal antibody conjugated to either 2-(p-SCN-Bz)-6-methyl-DTPA (1 B4M-DTPA) or 2-(p-SCN-Bz)-1,4,7,10-tetraazacyclododecane tetraacetic acid (2B-DOTA)

The biodistribution of indium-111/yttrium-88-labeled B3 monoclonal antibody, a murine IgG1k, was evaluated in non-tumor-bearing mice. B3 was conjugated to either 2-(p-SCN-Bz)-6-methyl-DTPA (1B4M) or 2-(p-SCN-Bz)-1,4,7,10 tetraazacyclododecane tetra-acetic acid (2B-DOTA) and labeled with ¹¹¹In at 1.4–2.4 mCi/mg and ⁸⁸Y at 0.1–0.3 mCi/mg. Non-tumor-bearing nude mice were co-injected i.v. with 5–10 Ci/4–10 g of ¹¹¹In/⁸⁸Y-labeled B3 conjugates and sacrificed at 6 h and daily up to 168 h post-injection. Mice injected with ¹¹¹In/⁸⁸Y (IB4M)-B3 showed a similar biodistribution of the two radiolabels in all tissues except the bones, where significantly higher accretion of ⁸⁸Y than ¹¹¹In was observed, with 2.8% ± 0.2% vs 1.3% ± 0.16% ID/g in the femur at 168 h, respectively (P<0.0001). In contrast, mice receiving the ¹¹¹In/⁸⁸Y-(DOTA)-B3 conjugate showed significantly higher accumulation of ¹¹¹In than ⁸⁸Y in most tissues, including the bones, with 2.0% ± 0.1% vs 1.2% ± 0.09% ID/g in the femur at 168 h, respectively (P<0.0001). Whereas the ratios of the areas underneath the curve (%ID × h/g) in the blood, liver, kidney and bone were 0.96, 1.12, 1.13, and 0.74 for ¹¹¹In/⁸⁸Y-(IB4M)-B3 and 0.84, 1.23, 1.56, and 1.31 for ¹¹¹In/⁸⁸Y (DOTA)-B3, respectively, ratios 1 were observed between ¹¹¹In-(IB4M)-B3 and ⁸⁸Y-(DOTA)-B3. In summary, while neither IB4M nor DOTA was equally stable for ¹¹¹In and ⁸⁸Y, the fate of ⁸⁸Y- (DOTA)-B3 could be closely traced by that of ¹¹¹ In-(IB4M)-B3.     

Simple scintigraphic parameters with Tc-99m galactosyl human serum albumin for clinical staging of chronic hepatocellular dysfunction

Technetium-99m labeled diethylenetriaminepentaacetic acid (DTPA)-galactosyl human serum albumin (GSA) has been used for hepatocellular functional evaluation. This study proposed new and simple parameters to overcome the limitations of conventional parameters, and they were applied to the clinical staging of chronic liver dysfunction. The study group consisted of 93 patients including 81 with liver dysfunction and 12 control patients. In addition to the two conventional parameters, namely, receptor index (LHL15 = liver count divided by the sum of liver and heart counts at 15 minutes) and clearance index (HH15 = heart count at 15 minutes divided by the heart count at 3 minutes), 6 new parameters for Tc-99m GSA uptake and clearance were generated. The conventional receptor index of LHL15 showed a large variation depending on the size of region of interest (ROI) over the heart. The LHL15 normalized by the ROI size (nLHL15) showed more stable data and a better separation of mild liver dysfunction. A hyperbolic relationship between the LHL15 and HH 15 changed to a linear relationship by using the nLHL15 index. The combination of the liver to heart average count ratio at 15 minutes (LH 15) and T-half (minute) of the heart count also could differentiate each stage well. In conclusion, the use of the ROI-area normalized nLHL is recommended instead of the conventional LHL15. The indices of LH15 and T-half could be alternatively used as practical parameters for clinical staging in liver function.     

Thallium-201 SPECT with triple-headed gamma camera for differential diagnosis of small pulmonary nodular lesion 20 mm in diameter or smaller

AIM: Although thallium-201 (201Tl) has been used for the diagnosis of lung cancer, its detectability of small pulmonary nodules is not known. The aim of this study was to evaluate the ability of 201Tl SPECT for the differential diagnosis for the pulmonary nodules 20 mm in diameter or smaller. METHODS: 201Tl SPECT was performed in 31 patients suspected of having primary lung cancer. The final diagnosis was established by histology, and tumor size was 10 to 20 mm in diameter. Twenty of 31 patients had malignant tumors, including squamous cell lung cancer (n = 5), adenocarcinoma (n = 14) and small cell lung cancer (n = 1), but in none of them was there mediastinal lymphnode involvement. RESULTS: Ten of 20 malignant tumors and 1 of 11 benign lesions demonstrated significant 201Tl uptake, so that the positive predictive value, negative predictive value, sensitivity and specificity for the diagnosis of lung cancer were 90.9% (10/11), 50.0% (10/20), 50.0% (10/20) and 90.9% (10/11), respectively. CONCLUSION: These data suggest that sensitivity for detecting lung cancer 20 mm or less in diameter may be insufficient, but even in patients with small pulmonary nodules, a positive 201Tl result is highly predictive of lung cancer.     

Quantification of Myocardial Perfusion Defect Size in Rats: Comparison between Quantitative Perfusion SPECT and Autoradiography

Purpose

Ultra-high resolution single-photon emission computed tomography (SPECT) system, using multiple pinhole collimators, has been applied to the imaging of small rodents. We aimed to compare the myocardial infarction (MI) area on quantitative perfusion single-photon emission computed tomography (QPS; Cedars-Sinai Medical Center, USA) with that on high-resolution autoradiography in rat model to determine the accuracy of perfusion defect measurement by QPS.

Procedures

After thoracotomy, rats (n?=?9) had their left coronary arteries occluded and reperfused before injection with 185 MBq [^99mTc] methoxyisobutylisonitrile ([^99mTc]MIBI) for SPECT and autoradiography. Healthy rats (n?=?28) were similarly scanned to create a normal database on which to base QPS. The MI area on SPECT images was analysed automatically by QPS software. For the autoradiography images, regions of interest for MI were set at 1 mm intervals.

Results

In normal rats, [^99mTc]MIBI accumulated throughout the left ventricles, and a polar map of ventricular perfusion showed the lowest and highest uptakes in the inferior (68 %?±?4 %) and anterior (92 %?±?5 %) walls, respectively. In the rat MI model, the percentage of polar map with reduced [^99mTc]MIBI uptake correlated strongly with the percentage of left ventricle with MI on autoradiography (r²?=?0.90).

Conclusions

QPS can quantitatively evaluate MI severity on myocardial perfusion images in rats, with comparable results to autoradiography. This widely available software could promote the development of new techniques for analysing cardiac images in small animals.

     

Fundamental study of radiogallium-labeled aspartic acid peptides introducing octreotate derivatives

Annals of Nuclear Medicine - Somatostatin receptors are highly expressed in neuroendocrine tumors, and many radiolabeled somatostatin analogs for diagnosis and treatment have been developed. To...     

Introduction of the targeted alpha therapy (with Radium-223) into clinical practice in Japan: learnings and implementation

Annals of Nuclear Medicine - Radium-223 dichloride (Ra-223) is the first targeted alpha therapy approved for the treatment of patients with castration-resistant prostate cancer (CRPC) with bone...     

High-dose 131I-metaiodobenzylguanidine therapy in patients with high-risk neuroblastoma in Japan

Annals of Nuclear Medicine - The aim of the study was to investigate the outcomes and prognostic factors of high-dose 131I-metaiodobenzylguanidine (131I-MIBG) therapy in patients with refractory or...     

Thyroid calcifications: sonographic patterns and incidence of cancer

We investigated the incidence of cancer in surgically resected 151 thyroid nodules in 101 patients according to their calcification patterns on preoperative ultrasonography (US). Calcification was detected in 57 (38%) nodules, 31 (54%) of which was histologically diagnosed as cancer. According to the calcification types, 9 of 11 nodules with microcalcifications, 15 of 29 nodules with intranodular coarse calcification, 6 of 14 nodules with peripheral calcification and 1 of 3 calcified spots without surrounding tumor were diagnosed as cancer.     

Intense 201 Tl uptake in giant-cell tumour of bone

The aim of this study was to determine the characteristics and clinical usefulness of 201Tl scintigraphy in giant-cell tumour of bone (GCT). Twenty-one patients with histopathologically proven benign GCT (22 lesions; 18 primary and four recurrent) underwent 201Tl scintigraphy. We also studied conventional osteosarcoma (10 lesions), a very common primary malignant bone tumour; and chordoma in the sacrum (four lesions), an entity requiring differential diagnosis from GCT of the sacrum. Early and delayed planar imaging was performed at 15 min (early) and 3 h (delayed) after the intravenous injection of 201Tl chloride (111 MBq). The Tl uptake ratio was calculated by dividing the count density of the tumour region of interest (ROI) by that of the background ROI. All GCT lesions showed increased Tl uptake in both early and delayed images. The mean Tl uptake ratios of primary GCT were 4.7 (range, 2.0-11.1) in the early images and 2.2 (range, 1.4-3.6) in the delayed images, and those of recurrent lesions were 5.8 (range, 2.4-11.5) in the early images and 2.7 (range, 2.0-4.3) in the delayed images. There were no significant differences between the uptake ratios in GCT and osteosarcoma, but the values of GCT tended to be higher than those of osteosarcoma, 3.1 (range, 1.7-4.4) in the early images and 1.8 (range, 1.3-2.3) in the delayed images. Chordoma did not show appreciable Tl uptake: the uptake ratio was 1.19 (range, 0.98-1.5) in the early images and 1.1 (range, 1.0-1.3) in the delayed images. In GCT, a benign lesion, Tl scintigraphy demonstrated marked uptake in both primary and recurrent lesions with no exceptions, precluding the use of Tl scintigraphy for the differential diagnosis of GCT from malignant tumours. However, the Tl scintigraphy can be used for excluding GCT when no lesional Tl uptake is observed, and diagnosing recurrent lesions on post-operative follow-up.