Table 1.

Summary of the recent studies (all xenografts were grown in mice).

Imaging modality	Probe	Tumor Model or Clinical Trial	Major Findings	Ref.
PET	89Zr-trastuzumab	SKBR3 xenografts	Detection of the changes in HER2 expression following treatment with DMAG	22
PET	89Zr-trastuzumab	Clinical trial	Quantification of the uptake is possible, optimally 4–5 days post injection	23
PET	124I-ZHER2:342 124I-trastuzumab	NCI-N87 xenografts	Using 124I-ZHER2:342 resulted in higher tumor-to-organ ratios as compare to 124I-trastuzumab	26
PET	111In-ABY-002 68Ga-ABY-002	SKBR3 xenografts	Rapid clearance of 68Ga-ABY-002 blood and healthy tissues (except kidneys) resulted in high tumor to organ ratios as soon as 2 h after injection	27
PET SPECT	111In-ABY-002 68Ga-ABY-002	Clinical trial	High-contrast SPECT or PET images of HER2-positive tumors can be obtained in humans as soon as 2–3 h after injection	28
PET	64CU-DOTA-ZHER2:477 (64CU-DOTA-ZHER2:477)2	SKOV3 xenografts	Monomer resulted in higher tumor accumulation and tumor/blood ratio as compared to dimer	29
PET	(18F-FBEM)-ZHER2:342	SKOV3 xenografts	The readioactivity was eliminated quickly from the blood and normal tissues, including the kidneys and liver, providing high tumor/blood and tumor/muscle ratios as soon as 1 h post injection	31
PET	18F-FBEM-ZHER2:342	BT474, MD-MBA-361,MCF7,and U251 xenogrfts	HER2 expression and its changes caused by therapeutic intervention can be monitored by PET	32
PET	68Ga-DOTA-MUT-DS	SKOV3 xenografts	The probe bound to HER2 with high affinity, was stable in mouse serum, had rapid and high tumor accumulation, and was quickly cleared from normal organs	33
SPECT	111In-DTPA-trastuzumab	MDA-MB-231,MDA-MB-361, SKBR-3,Bt-20, BT474, BY474het, MCF7/HER2-18 xenografts	Tumor response to Herceptin depends on HER2 expression	34
SPECT	111In-DTPA-pertuzumab	MDA-MB-361 xenografts	Decrease of 111In-DTPA-pertuzumab uptake following treatment with trastuzumab associated eradication of HER2-positive tumor cells	35
SPECT	99mTC-ZHER2:2395-CyS	LS174T, SKOV-3 xenografts	Rapid accumulation in HER2-positive xenografts and rapid clearance from a majority of organs (except for the kidneys and liver) allowed clear visualization of HER2 expression within a few hours after injection	36
MRI	Trastuzumab-conjugated, dextran-modified iron oxide nanoparticles	BT-474, SKBR-3, MDA-MB-231, MCF-7 xenografts	The HER2-specific nanoparticles bound specially to HER2-positive cells and allowed visualization of HER2-posive xenografts by a 3-T MRI scanner using T2-weighted fast spin-echo sequence	37
MRI	Affibody-SPIO nanoparticles	SKOV-3 xenografts	The nanoparticles bound specifically to HER2, and the tumor could be clearly seen imaged on MRI using a gradient-echo sequence	38
Optical Imaging	111In and indocyanine green-labeled trastuzumab	MDA-MB-468, A431, 3T3/HER2 xenografts	Multimodality imaging following injection of dual labeled, radio-optical probes provides data on biodistribution profile of the injected antibody by nuclear imaging and allows the target specific tumor visualized by optical imaging.	45
Optical Imaging	AlexaFluor-labeled (ABD)-(ZHER2:342)2-Cys Affibody molecules	BT474, MD-MBA-361,MCF7,and U251 xenogrfts	Initial slope of the curve characterizing the temporal dependence of the fluorescence intensity detected in the tumor depends linearly on HER2 expression	47