Macroaggregated albumin

M.B. Use of macroaggregated albumin lung perfusion scan to diagnose hepatopulmonary syndrome a new approach. Gastroenterology 1998 114 305-310... 

Surfactants might be required to solubilize lipophilic Tc complexes (MIBI) (Berg-stein and Subramanyam 1986) and particulate preparations (macroaggregated albumin, microspheres). 

Commercial kits contain the lyophilized, sterile components in a multidose vial, sealed under a nitrogen atmosphere. Labeling is carried out by adding aseptically a volume of 2-10 ml of sterile Tc-pertechnetate to the vial with an activity up to 3.7 GBq. The manufacturer s instructions should be followed. The lyophilized material will dissolve by agitating the reaction vial. The reaction should be allowed to proceed for 5-20 min, with occasional agitation. Tc-macroaggregated albumin (MAA) is a pale-white suspension ready for intravenous injection. The pH of the suspension is 3.5-7.5. 

Heyman S (1979) Toxicity and safety factors associated with lung perfusion studies with radiolabeled particles (letter to the editor). J Nucl Med 20 1098-1099 International Commission on Radiological Protection (1987) Technetium-labelled macroaggregated albumin. In Armais of the ICRP. Radiation dose to patients from radiopharmaceuticals, bioki-netic models and data. ICRP publication 53, vol. 18, no. 1-4. Pergamon, Oxford, pp 223-224 Malone LA, Malone JF, Ennis JT (1983) Kinetics of technetium 99m-labelled macroaggregated albumin in humans. Br J Radiol 56 109-112... 

Taplin GV, Chopra SK (1978) Lung perfusion-inhalation scintigraphy in obstructive airway disease and pulmonary embolism. Radiol Clin N Am 16 491-513 Taplin GV, MacDonald NS (1971) Radiochemistry of macroaggregated albumin and newer lung scanning agents. Sem Nucl Med 1 132-152... 

Tc-macroaggregated albumin, Tc-albumin microspheres, Tc-albumin minimicrospheres, Tc- erric hydroxide aggregates, Tc-sulfur colloid, Tc-antimony colloid, Tc-phytate... 

Ho S, Lau WY, Leung TW et al (1997) Tumour-to-normal uptake ratio of 90Y microspheres in hepatic cancer assessed with 99Tcm macroaggregated albumin. Br J Radiol 70 823-828... 

Dhabuwala A, Lamerton P, Stubbs RS (2005) Relationship of 99mtechnetium labelled macroaggregated albumin (99mTc-MAA) uptake by colorectal liver metastases to response following Selective Internal Radiation Therapy (SIRT). BMC Nucl Med 5 7... 

Taking these potential risks into account, it is mandatory to simulate SIR-Spheres distribution prior to the therapy. This can be accomplished with 99mTc-iabeled macroaggregated albumin (MAA) injected into the hepatic artery similar to the application during microsphere treatment. MAA is typically injected selectively into the right and left liver arteries with a right-to-left ratio corresponding to... 

Fig. 8.1, Safety assessment prior to SIR-Spheres therapy. Scintigraphy with macroaggregated albumin (MAA) acquired after intraarterial administration of MAA during hepatic angiography shows extrahepatic deposition of particles. A therapeutic application of microspheres under the same conditions would have resulted in severe complications...

Although the average particle size of macroaggregated albumin (35 pm) is similar to that of SIR-Spheres (29-35 pm), the size range of MAA particles is broader (10-60 pm) and the shape of the MAA particles may be different from therapeutic microspheres. A clinically relevant impact of these differences in physical properties, however, has not yet been reported. 

Nuclear medicine procedures play a substantial role in patient selection, therapy planning, treatment monitoring and follow-up. F-FDG PET/CT, SPECT with macroaggregated albumin and post-therapeutic bremsstrahlung scintigraphy are the most important techniques used for this purpose. 

Leung WT, Lau WY, Ho SK et al (1994) Measuring lung shunting in hepatocellular carcinoma with intrahepatic-arterial technetium-99m macroaggregated albumin. J Nucl Med 35 70-73... 

This estimation will be supported by the results of the technetium-99m macroaggregated albumin scanning ( Tc MAA scan) necessary to assess potential pulmonary shunting (see below). 

Hung JC et al. (2000) Evaluation of macroaggregated albumin particle sizes for use in pulmonary shunt studies. J Am Pharm Assoc 40 46-51... 

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