Objective
Between 60% and 84% of cancer patients with solid tumors develop bone metastases. Several radiopharmaceuticals for treating painful bone metastases have been developed. Worldwide 177Lu-labeled compounds are under investigation for various clinical applications in the field of nuclear medicine.Bio-evaluation studies with three potential therapeutic radioapharmaceuticals (177Lu-MDP, 177Lu-PYP and 177Lu-HA) may result in generating information about their usefulness for the treatment of bone cancer and Rheumatoid Arthritis.
Materials and Method
In this study, kit vials of MDP and Na-PYP were formulated and HA (Hydroxyapatite) particles were synthesized locally.
177Lu was produced by irradiating natural Lu2O3(10mg) target at a thermal flux ~8.0×1013n /cm2/s for 12h in the swimming pool type reactor.177Lu was labeled with all the three chemicals. Animals were anesthetized and injected with 177Lu-MDP, 177Lu-PYP and 177Lu-HA. Bio evaluation studies with gamma-camera were carried out to acquire the sequential planner images.
Results
Gamma camera images recorded at 22h p.i of 177Lu- MDP complex and 24h p.i of 177Lu- PYP complex with dual head camera showed significant activity in the skeleton. Images acquired at 722 hours p.i of 177Lu-HA particles in the knee joints of two rabbits showed no activity in any organ other than knee joints.
Conclusions:
Biodistribution studies in Sprague Dawley rats injected with 177Lu- MDP indicated selective bone accumulation, suggesting that it may be useful as a bone- pain palliation agent for the treatment of bone metastases.Gamma camera images of a rabbit injected with 177Lu- PYP tooindicated higher skeletal uptake suggesting that it may also be useful as a bone- pain palliation agent for the treatment of bone metastases. On the basis of good retention of activity shown by the injected177Lu-HA particulates in animal model, the use of 177Lu-HA particles in human beings for the treatment of arthritis of small joints could safely be suggested.