Whole-body imaging study with 177Lu-EDTMP in patients: As a new therapeutical agent of bone metastasis

Objectives [177]Lu-EDTMP as a beta-emitting bone-seeking therapeutical agent for bone pain palliation also can emit suitable energy gamma photons of 113 keV (6.4%) and 208 keV (11%) for imaging. We describe the conditions of SPECT whole-body imaging with [177]Lu-EDTMP in patients.

Methods Subjects suffering with bone matastasis from prostate or breast cancer were included in this study. Whole-body scans were performed at three time phases of 0.5-2hr, 24hr and 48hr after injection of 177Lu-EDTMP. In each phase, scans were acquired with a multi-energy window setting of A:113KeV±10% and B:208KeV±7.5% with LEHR and MELP collimates successively. We compared these series of images including [99m]Tc-MDP scans to choose suitable imaging conditions for 177Lu-EDTMP.

Results Comparison by either femur-to-muscle uptake rate or lesion-to-normal bone uptake rate or just eye-viewing shows that image from 208keV with MELP has highest quality and those from 103keV with MELP and 103keV with LEHR are in order. 24hr and 48hr phases are suitable time slots to gain clear bone imaging. Quality of images from 208keV with LEHR collimators is too poor to be used for imaging, differing with the result of some articles on animal.

Conclusions The ideal condition of whole-body [177]Lu-EDTMP scanning is employing medium energy collimator (eg, MELP) and using 208KeV energy or using both 208 KeV and 113KeV energy windows for acquiring more counts. The best time slots for imaging is about 24-48hr after administration of the agent.

Research Support IAEA Research Contract Number 1526