Highlights
- Dynamic 4D SPECT imaging of ¹⁷⁷Lu-Trastuzumab from 3 to 53 min post injection
- 5-min frame duration, including 3 min of effective acquisition per frame
- Time-resolved whole-body visualization during the early post-injection period
Introduction
Time-resolved imaging during the early post-injection period provides insight into changes in whole-body radiopharmaceutical distribution over time. This application demonstrates dynamic 4D SPECT imaging of ¹⁷⁷Lu-Trastuzumab in a SKOV-3 xenograft model using sequential SPECT acquisitions from 3 to 53 min post injection.
Study design
¹⁷⁷Lu-Trastuzumab was evaluated in a SKOV-3 xenograft model using the γ-eye™ system.
For the dynamic proof-of-concept acquisition, SPECT imaging was performed from 3 to 53 min post injection, with 40.2 MBq of activity during imaging. The effective acquisition time was 3 min per frame, with a total frame duration of 5 min including detector repositioning.
Results
Dynamic SPECT imaging
Sequential SPECT frames provided time-resolved whole-body visualization throughout the early post-injection period, from 3 to 53 min post injection.
During the early frames, activity is broadly distributed across the thoracoabdominal region, together with prominent activity in the urinary bladder. As the acquisition progresses, the signal becomes more localized, while diffuse background activity decreases and bladder activity remains prominent, consistent with urinary excretion.
The dynamic sequence illustrates both the redistribution and clearance of the radiopharmaceutical during the first hour following administration.
Figure 1: Dynamic SPECT imaging of ¹⁷⁷Lu-Trastuzumab in a SKOV-3 xenograft model from 3 to 53 min post injection. Activity during imaging: 40.2 MBq. Effective acquisition time: 3 min per frame. Total frame duration: 5 min, including detector repositioning.
Conclusion
Dynamic 4D SPECT provides time-resolved visualization of ¹⁷⁷Lu-Trastuzumab distribution during the early post-injection period, allowing changes in whole-body radiopharmaceutical distribution to be followed within a single imaging session.
Sequential SPECT acquisitions with 5-min temporal frames extend conventional static imaging by adding temporal information to the spatial assessment of radiopharmaceutical behavior.