Abstract
Recent studies suggest a high specificity of 99mTc-galactosyl neoglycoalbumin (99mTc-NGA) receptor scanning in vivo by providing both morphological and functional diagnosis of liver disease. In 22 patients with advanced breast cancer 99mTc-NGA (150 MBq; 50 nmol) was exclusively trapped by the liver, the images showing 'cold spots' in areas of liver metastases formation. A two-tailed analysis was performed: the time activity curves recorded for the liver and precordial area were subjected to a kinetic receptor-calculating model allowing an estimation of the NGA-receptor concentration of the liver (i.e. hepatic binding protein, HBP) as well as calculation of the residual functional liver volume (RFLV) via the S.P.E.C.T.-study. In breast cancer patients with liver metastases a significantly (P < 0.01) lower HBP-concentration was estimated (0.65 +/- 0.16 vs 0.82 +/- 0.17 mumol l-1) as evidenced by a lower 99mTc-NGA-accumulation in the liver resulting also in a significantly (P < 0.001) lower RFLV (739 +/- 348 vs 1336 +/- 184 ml). In four amonafide-treated patients (800 mg m-2 intravenous infusion over 3 h) approximately one week after one chemotherapy cycle a significant (P < 0.05) increase in HBP-concentration (0.56 +/- 0.10 vs 0.72 +/- 0.06 mumol l-1) of the liver was found corresponding with an increase in RVLF (546 +/- 297 vs 670 +/- 265 ml). These regulatory mechanisms at the HBP level measured in vivo provide further evidence that 99mTc-NGA should have promise as a clinically useful receptor radiopharmaceutical for both quantification of liver function and assessment of liver morphology.