technetium-tc-99m-exametazime and Neoplasms

In the past 7 years, single photon emission computed tomography (SPECT) has evolved from an interesting nuclear medicine technique rarely performed because of technical difficulties into a valuable clinical tool in the management of cancer cases. The development of stable multidetector instruments with collimators and gantries specifically designed for SPECT and the introduction of new radiopharmaceuticals recently approved by the U.S. Food and Drug Administration have rapidly moved SPECT from the field of clinical investigation to clinical practice. SPECT is a valuable addition to other tomographic modalities capable of displaying the physiology of disease as well as anatomy. In this work the authors describe the role of SPECT in a cancer center and, in particular, how they use it to solve clinical problems. They also review the published literature, when appropriate. The authors have found SPECT of particular value in evaluation of myocardial ischemia, in differentiating tumor recurrence from posttherapy changes in the lymphomas, in tumor diagnosis and surveillance, and in separating hemangioma from malignant lesions in the liver.

Topics: Abdomen; Amphetamines; Antibodies, Monoclonal; Bone Diseases; Brain Diseases; Cardiovascular Diseases; Humans; Neoplasms; Organotechnetium Compounds; Oximes; Quality Control; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Targeted delivery of radionuclides and therapeutic agents to specific biomarkers of breast cancer has important implications for the diagnosis and therapy of breast cancer. Vasoactive intestinal peptide receptors (VIP-R) are approximately five times more expressed in human breast cancer, compared to normal breast tissue. We have used VIP, a 28 amino acid mammalian neuropeptide, as a breast cancer targeting moiety for targeted imaging of breast cancer. VIP was covalently attached to the surface of sterically stabilized liposomes (SSL) that encapsulated a radionuclide, Tc99m-HMPAO. Rats with n-methyl nitrosourea (MNU)-induced in situ breast cancers were used to test this targeted liposomal imaging agent. Specifically, the pharmacokinetics and biodistribution of Tc99m-HMPAO encapsulating SSL with and without VIP were determined together with their ability to image breast cancer. The presence of VIP did not alter the size and Tc99m-HMPAO encapsulation ability of SSL. It also did not alter the pharmacokinetic profile of SSL. Long-circulating liposomes with and without VIP on their surface accumulated at significantly higher quantities in breast cancer when compared to normal breast, indicating passive targeting of these constructs to cancer tissues. Importantly, in breast cancer, Tc99m-HMPAO encapsulating SSL with VIP showed significantly more accumulation than SSL without VIP. The tumor to non-tumor ratio was also significantly higher for Tc99m-HMPAO encapsulating VIP-SSL than Tc99m-HMPAO encapsulating SSL without VIP, suggesting active targeting of VIP-SSL to breast cancer. Collectively, these data showed that Tc99m-HMPAO encapsulating VIP-SSL can be successfully used for the targeted imaging of breast cancer.

Topics: Animals; Carcinogens; Drug Carriers; Drug Compounding; Female; Image Processing, Computer-Assisted; Liposomes; Mammary Neoplasms, Experimental; Methylnitrosourea; Neoplasms; Particle Size; Radionuclide Imaging; Radiopharmaceuticals; Rats; Technetium Tc 99m Exametazime; Tissue Distribution; Vasoactive Intestinal Peptide

A number of radiopharmaceutical agents have been evaluated for the detection of malignant melanoma. Because anamine is necessary for melanin synthesis, melanotic tumors may possess numerous amine receptors. Tc-99m HMPAO consists of macrocyclic amine radicals. The purpose of this study was to evaluate Tc-99m HMPAO as an effective agent for localizing malignant melanomas on the radioisotope imaging. Six patients, with malignant melanomas were studied. Tc-99m HMPAO SPECT images were obtained in all patients. SPECT was used for the localization of the primary focus, and whole body scans were used for the evaluation of unexpected metastatic lesions. The results were compared with MRI and CT. Tc-99m HMPAO SPECT revealed a high correlation with CT and MRI for the primary focus. Abnormally increased activity at the unexpected metastatic lymph nodes in two patients were also noticed. This was confirmed by CT and MRI for those sites. Tc-99m HMPAO appears to be a useful agent for the localization of both the primary focus and unexpected metastatic lesion in patients with malignant melanoma.

Topics: Aged; Female; Humans; Magnetic Resonance Imaging; Male; Melanoma; Middle Aged; Neoplasms; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Tumor imagings have been performed in 32 tumor sites in 28 patients with a variety of malignancies by using 99mTc-HM-PAO. They have been compared with radionuclide angiography and conventional tumor imagings such as 67Ga citrate or 201TlCl scanning, and then their possible values have been evaluated for the investigation of tumor blood flow. Tumors were clearly visualized in 19 out of 32 sites, with 59% of positive rate. Good correlation was observed between the radioactivity in the tumor site on static image of 99mTc-HM-PAO and the radioactivity at arterial phase on radionuclide angiography, which represents tumor blood flow. The radioactivities in the marginal regions tended to be stronger than those in the center of large tumors. These results indicated that tumor imaging by 99mTc-HM-PAO mainly reflected tumor blood flow. On the other hand, 99MTc-HM-PAO imagings were not well correlated with 67Ga-studies, while they were coincided with all 201Tl scannings performed. It suggested that the affinity of 99mTc-HM-PAO to capillary wall also involved in its accumulation in the tumor. In conclusion, tumor imaging by 99MTc-HM-PAO was able to estimate tumor blood flow, and this examination would be helpful for the management of malignancies.

Topics: Adult; Aged; Citrates; Citric Acid; Female; Gallium Radioisotopes; Humans; Male; Middle Aged; Neoplasms; Organotechnetium Compounds; Oximes; Radionuclide Angiography; Technetium Tc 99m Exametazime; Thallium Radioisotopes

Topics: Humans; Neoplasms; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

Technetium-99m-labelled hexamethylpropylene amine oxime (HM-PAO) has been used to investigate tumour perfusion in 11 tumour sites in 8 patients with a variety of histologies. In 8 out of 11 instances single photon emission tomography clearly distinguished between tumour and normal tissues; in 7 cases due to increased HM-PAO uptake and in 1 due to reduced tumour uptake compared with hepatobiliary excretion of HM-PAO in adjacent normal liver. Heterogeneous uptake within individual tumour masses was observed in 3 cases. In 2 where a correlation between the pathology of excised tumour and the scan findings could be made, the findings were consistent with HM-PAO uptake in well-perfused tissue. These preliminary observations suggest that Technetium-99m-HM-PAO may be a valuable clinical technique for displaying patterns of tumour perfusion.

Topics: Humans; Neoplasms; Organometallic Compounds; Oximes; Perfusion; Regional Blood Flow; Technetium; Technetium Tc 99m Exametazime; Tomography, Emission-Computed