Preclinical imaging of therapy response using metabolic and apoptosis molecular imaging.
OBJECTIVE
Early after therapy, 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) imaging is not always reliable due to the influx of inflammatory cells while apoptosis imaging offers a direct and early measurement of therapy effects. This study uses an improved apoptosis probe ((99m)Tc-hAnxA5) in combination with [(18)F]FDG imaging to evaluate therapy response.


METHODS
Daudi tumor tissue was implanted in the spleen of SCID mice. Treatment was performed with adriamycin and cyclophosphamide. Sequential [(18)F]FDG-positron emission tomography (PET) was acquired over 6 days and (99m)Tc-hAnxA5-SPECT was performed before and 1 day after therapy.


RESULTS
On day 1, therapy induced apoptosis was visualized with (99m)Tc-hAnxA5 without a measurable change in [(18)F]FDG uptake. [(18)F]FDG uptake decreased significantly on day 3 and was even more pronounced on day 6.


CONCLUSIONS
In this preclinical model, (99m)Tc-hAnxA5 imaging was able to detect apoptosis before metabolic changes were measured. These results confirm the value of apoptosis imaging for therapy response and give more insight in [(18)F]FDG imaging and its parameters to evaluate response.
De Saint-Hubert
Marijke
M
Department of Nuclear Medicine, University Hospital Gasthuisberg Leuven, Leuven, Belgium.
Wang
Huijun
H
Devos
Ellen
E
Vunckx
Kathleen
K
Zhou
Lin
L
Reutelingsperger
Chris
C
Verbruggen
Alfons
A
Mortelmans
Luc
L
Ni
Yicheng
Y
Mottaghy
Felix M
FM
D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D006801:Humans; D008223:Lymphoma / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D051379:Mice; D016513:Mice, SCID; D049268:Positron-Emission Tomography; D015899:Tomography, Emission-Computed, Single-Photon