Lactoperoxidase (LPO) inhibitors are very selective for solid tumor due to their high binding affinity to the LPO enzyme. A computational study was used to select top-ranked LPO inhibitor (alone and in complex with 99mTc) with high in silico affinity. The novel prepared 99mTc-amitrole complex demonstrated both in silico and in vivo high affinity toward solid tumors. 99mTc-amitrole was radio-synthesized with a high radiochemical yield (89.7 ± 3.25). It showed in vitro stability for up to 6 h. Its preclinical evaluation in solid tumor-bearing mice showed high retention and biological accumulation in solid tumor cells with a high Target/Non-Target (T/NT) ratio equal to 4.9 at 60 min post-injection. The data described previously could recommend 99mTc-amitrole as potential targeting scintigraphic probe for solid tumor imaging
