Osseous metastases imaging with 177Lutetium
labeled with prostate-specific membrane antigen (J591). Corresponding bone-scan
images are used for comparison.
Whole body bone-scan showing increased radiopharmaceutical uptake in the
left scapula, and bilateral iliac bones. 177Lutetium-J591 imaging
shows corresponding osseous uptake at sites of osseous metastases with hepatic
clearance. Single photon emission computed tomography/computed tomography (SPECT/CT)
images confirm sites of increased osseous uptake.
Targeted molecular therapy techniques provide a new avenue for cancer imaging
and therapy. Monoclonal antibodies (mAbs) are developed to specific cancer
antigens and conjugated to radionuclides to produce cancer-specific
radiopharmaceuticals. Imaging agents such as 111Indium can be
followed by therapy agents such as 90Yttrium to map and treat
metastatic cancer deposits. Other radiopharmaceuticals can be produced with
agents such as 177Lutetium and 131Iodine for both
diagnosis and therapy in a single administration.
J591 is the first mAb targeting the extracellular domain of prostate-specific
membrane antigen (PSMA), which is expressed by all prostate cancers. There is
further evidence that PSMA is more highly expressed in cancers that are poorly
differentiated, metastastic, and hormone refractory. Currently in phase II
trials, this agent may provide a molecule specific therapy for hormone refractory
disease. The antibody is non-immunogenic and can be administered multiple times
to the same patient with persistent accurate targeting.
1. Bouchelouche K, Tagawa ST, Goldsmith SJ, et al. PET/CT imaging and radioimmunotherapy
of prostate cancer. Semin Nucl Med.
2. Bander NH, Trabulsi EJ, Kostakoglu L, et al. Targeting metastatic
prostate cancer with radiolabeled monoclonal antibody J591 to the extracellular
domain of prostate specific membrane antigen. J Urol. 2003;170:1717-1721.