The preparation of 99mTc-DTPA-LSA and its instant lyophilized kit for hepatic receptor imaging.

Diethylenetriaminepentaacetic acid neolactosyl human serum albumin (DTPA-LSA) was prepared and labeled with technetium-99m. The labeling conditions of (99m)Tc-DTPA-LSA were optimized, and lyophilized kit was developed for instant preparing of (99m)Tc-DTPA-LSA. (99m)Tc-DTPA-LSA showed high liver uptake in normal mice (>96% ID/g at 5min after injection), and it could be blocked significantly by pre-injecting free neogalactosylalbumin (NGA). Single photon emission computed tomography (SPECT) study was performed in normal Japanese White rabbits and SPECT images with high quality were obtained at 15, 30, 60, and 120min after injection of the radiotracer. The promising biological properties of (99m)Tc-DTPA-LSA combined with the development of reliable and instant lyophilized DTPA-LSA kit afford the opportunity of hepatic receptor imaging for routine clinical assessment of hepatic function.

On-site preparation of technetium-99m labeled human serum albumin for clinical application.

Technetium-99m labeled human serum albumin (Tc-99m HSA) is an important radiopharmaceutical for clinical applications, such as cardiac function tests or protein-losing gastroenteropathy assessment. However, because of transfusion-induced infectious diseases, the safety of serum products is a serious concern. In this context, serum products acquired from patients themselves are the most ideal tracer. However, the development of rapid separation and easy clinical labeling methods is not yet well established. Under such situation, products from the same ethnic group or country are now recommended by the World Health Organization as an alternative preparation. This article describes the on-site preparation of Tc-99m HSA from locally supplied serum products. Different formulations were prepared and the labeling efficiency and stability were examined. Radio-labeling efficiencies were more than 90% in all preparation protocols, except for one that omitted the stannous solution. The most cost-effective protocol contained HSA 0.1 mg, treated with stannous fluoride 0.2 mg, and mixed with Tc-99m pertechnetate 30 mCi. A biodistribution study was performed in rats using a gamma camera immediately after intravenous administration of radiolabeled HSA. Tissue/organ uptake was obtained by measuring the radioactivity in organs after sacrificing the rats at timed intervals. The biologic half-life was about 32 min, determined from sequential venous blood collections. These data indicate that our preparation of Tc-99m HSA is useful and potentially applicable clinically. In addition, this on-site preparation provides the possibility of labeling a patient's own serum for subsequent clinical application.

Preparation of tin-albumin nanospheres for labelling with 99mTc and application in liver scintigraphy.

A modified method is described for the preparation of albumin nanospheres for labelling with 99mTc by investigating the absorption behaviour of tin as a reducing agent on albumin nanospheres. These albumin nanospheres can be used for studying the reticuloendothelial system, especially that of the liver. The labelling method is very simple, and the efficiency of labelling with 99mTc is higher than 97 per cent.