TY  - JOUR
A1  - Janssen, Jan P.
A1  - Hoffmann, Jan V.
A1  - Kanno, Takayuki
A1  - Nose, Naoko
A1  - Grunz, Jan-Peter
A1  - Onoguchi, Masahisa
A1  - Chen, Xinyu
A1  - Lapa, Constantin
A1  - Buck, Andreas K.
A1  - Higuchi, Takahiro
T1  - Capabilities of multi-pinhole SPECT with two stationary detectors for in vivo rat imaging
JF  - Scientific Reports
N2  - We aimed to investigate the image quality of the U-SPECT5/CT E-Class a micro single-photon emission computed tomography (SPECT) system with two large stationary detectors for visualization of rat hearts and bones using clinically available \(^{99m}\)Tc-labelled tracers. Sensitivity, spatial resolution, uniformity and contrast-to-noise ratio (CNR) of the small-animal SPECT scanner were investigated in phantom studies using an ultra-high-resolution rat and mouse multi-pinhole collimator (UHR-RM). Point source, hot-rod, and uniform phantoms with \(^{99m}\)Tc-solution were scanned for high-count performance assessment and count levels equal to animal scans, respectively. Reconstruction was performed using the similarity-regulated ordered-subsets expectation maximization (SROSEM) algorithm with Gaussian smoothing. Rats were injected with similar to 100 MBq [\(^{99m}\)TcTc-MIBI or similar to 150 MBq [\(^{99m}\)Tc]Tc-HMDP and received multi-frame micro-SPECT imaging after tracer distribution. Animal scans were reconstructed for three different acquisition times and post-processed with different sized Gaussian filters. Following reconstruction, CNR was calculated and image quality evaluated by three independent readers on a five-point scale from 1="very poor" to 5="very good". Point source sensitivity was 567 cps/MBq and radioactive rods as small as 1.2 mm were resolved with the UHR-RM collimator. Collimator-dependent uniformity was 55.5%. Phantom CNR improved with increasing rod size, filter size and activity concentration. Left ventricle and bone structures were successfully visualized in rat experiments. Image quality was strongly affected by the extent of post-filtering, whereas scan time did not have substantial influence on visual assessment. Good image quality was achieved for resolution range greater than 1.8 mm in bone and 2.8 mm in heart. The recently introduced small animal SPECT system with two stationary detectors and UHR-RM collimator is capable to provide excellent image quality in heart and bone scans in a rat using standardized reconstruction parameters and appropriate post-filtering. However, there are still challenges in achieving maximum system resolution in the sub-millimeter range with in vivo settings under limited injection dose and acquisition time.
KW  - small animal SPECT
KW  - HMDP hydroxymethylene diphosphonate
KW  - skeletal
KW  - quality
KW  - scanner
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-230616
VL  - 10
ER  - 
TY  - JOUR
A1  - Israel, Ina
A1  - Riehl, Gabriele
A1  - Butt, Elke
A1  - Buck, Andreas K.
A1  - Samnick, Samuel
T1  - Gallium-68-labeled KISS1-54 peptide for mapping KISS1 receptor via PET: initial evaluation in human tumor cell lines and in tumor-bearing mice
JF  - Pharmaceuticals
N2  - Kisspeptins (KPs, KISS1) and their receptor (KISS1R) play a pivotal role as metastasis suppressor for many cancers. Low or lost KP expression is associated with higher tumor grade, increased metastatic potential, and poor prognosis. Therefore, KP expression has prognostic relevance and correlates with invasiveness in cancers. Furthermore, KISS1R represents a very promising target for molecular imaging and therapy for KISS1R-expressing tumors. The goal of this study was to evaluate the developed KISS1-54 derivative, [\(^{68}\)Ga]KISS1-54, as a PET-imaging probe for KISS1R-expressing tumors. The NODAGA-KISS1-54 peptide was labeled by Gallium-68, and the stability of the resulting [\(^{68}\)Ga]KISS1-54 evaluated in injection solution and human serum, followed by an examination in different KISS1R-expressing tumor cell lines, including HepG2, HeLa, MDA-MB-231, MCF7, LNCap, SK-BR-3, and HCT116. Finally, [\(^{68}\)Ga]KISS1-54 was tested in LNCap- and MDA-MB-231-bearing mice, using µ-PET, assessing its potential as an imaging probe for PET. [\(^{68}\)Ga]KISS1-54 was obtained in a 77 ± 7% radiochemical yield and at a >99% purity. The [\(^{68}\)Ga]KISS1-54 cell uptake amounted to 0.6–4.4% per 100,000 cells. Moreover, the accumulation of [\(^{68}\)Ga]KISS1-54 was effectively inhibited by nonradioactive KISS1-54. In [\(^{68}\)Ga]KISS1-54-PET, KISS1R-positive LNCap-tumors were clearly visualized as compared to MDA-MB-231-tumor implant with predominantly intracellular KISS1R expression. Our first results suggest that [\(^{68}\)Ga]KISS1-54 is a promising candidate for a radiotracer for targeting KISS1R-expressing tumors via PET.
KW  - [\(^{68}\)]KISS1-54
KW  - KISS1 receptor
KW  - GPR54
KW  - kisspeptin
KW  - human tumor cell lines
KW  - positron emission tomography
KW  - PET
KW  - KISS1-54
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-355898
SN  - 1424-8247
VL  - 17
IS  - 1
ER  -