TY  - JOUR
A1  - Lückerath, Katharina
A1  - Lapa, Constantin
A1  - Albert, Christa
A1  - Herrmann, Ken
A1  - Jörg, Gerhard
A1  - Samnick, Samuel
A1  - Einsele, Herrmann
A1  - Knop, Stefan
A1  - Buck, Andreas K.
T1  - \(^{11}\)C-Methionine-PET: a novel and sensitive tool for monitoring of early response to treatment in multiple myeloma
JF  - Oncotarget
N2  - Multiple myeloma (MM) remains an essentially incurable hematologic malignancy. However, new treatment modalities and novel drugs have been introduced and thus additional tools for therapy monitoring are increasingly needed. Therefore, we evaluated the radiotracers \(^{11}\)C-Methionine (paraprotein-biosynthesis) and \(^{18}\)F-FDG (glucose-utilization) for monitoring response to anti-myeloma-therapy and outcome prediction. Influence of proteasome-inhibition on radiotracer-uptake of different MM cell-lines and patient-derived CD138\(^{+}\) plasma cells was analyzed and related to tumor-biology. Mice xenotransplanted with MM. 1S tumors underwent MET- and FDG-\(\mu\)PET. Tumor-to-background ratios before and after 24 h, 8 and 15 days treatment with bortezomib were correlated to survival. Treatment reduced both MET and FDG uptake; changes in tracer-retention correlated with a switch from high to low CD138-expression. In xenotransplanted mice, MET-uptake significantly decreased by 30-79% as early as 24 h after bortezomib injection. No significant differences were detected thus early with FDG. This finding was confirmed in patient-derived MM cells. Importantly, early reduction of MET-but not FDG-uptake correlated with improved survival and reduced tumor burden in mice. Our results suggest that MET is superior to FDG in very early assessment of response to anti-myeloma-therapy. Early changes in MET-uptake have predictive potential regarding response and survival. MET-PET holds promise to individualize therapies in MM in future.
KW  - positron emission tomography
KW  - imaging techniques
KW  - experience
KW  - \(^{11}\)C-Methionine-PET
KW  - treatment response
KW  - molecular imaging
KW  - multiple myeloma
KW  - management
KW  - \(^{18}\)F-FDG PET/CT
KW  - bone disease
KW  - stem-cell transplantation
KW  - esophagogastric junction
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148688
VL  - 6
IS  - 10
ER  - 
TY  - JOUR
A1  - Lassmann, Michael
A1  - Preylowski, Veronika
A1  - Schlögl, Susanne
A1  - Schoenahl, Frédéric
A1  - Jörg, Gerhard
A1  - Samnick, Samuel
A1  - Buck, Andreas K.
T1  - Is the Image Quality of I-124-PET Impaired by an Automatic Correction of Prompt Gammas?
JF  - PLoS ONE
N2  - Objectives

The aim of this study is to evaluate the quality of I-124 PET images with and without prompt gamma compensation (PGC) by comparing the recovery coefficients (RC), the signal to noise ratios (SNR) and the contrast to F-18 and Ga-68. Furthermore, the influence of the PGC on the quantification and image quality is evaluated.

Methods

For measuring the image quality the NEMA NU2-2001 PET/SPECT-Phantom was used containing 6 spheres with a diameter between 10 mm and 37 mm placed in water with different levels of background activity. Each sphere was filled with the same activity concentration measured by an independently cross-calibrated dose calibrator. The “hot” sources were acquired with a full 3D PET/CT (Biograph mCT®, Siemens Medical USA). Acquisition times were 2 min for F-18 and Ga-68, and 10 min for I-124. For reconstruction an OSEM algorithm was applied. For I-124 the images were reconstructed with and without PGC. For the calculation of the RCs the activity concentrations in each sphere were determined; in addition, the influence of the background correction was studied.

Results

The RCs of Ga-68 are the smallest (79%). I-124 reaches similar RCs (87% with PGC, 84% without PGC) as F-18 (84%). showing that the quantification of I-124 images is similar to F-18 and slightly better than Ga-68. With background activity the contrast of the I-124 PGC images is similar to Ga-68 and F-18 scans. There was lower background activity in the I-124 images without PGC, which probably originates from an overcorrection of the scatter contribution. Consequently, the contrast without PGC was much higher than with PGC. As a consequence PGC should be used for I-124.

Conclusions

For I-124 there is only a slight influence on the quantification depending on the use of the PGC. However, there are considerable differences with respect to I-124 image quality.
KW  - cancer treatment
KW  - health care
KW  - isotopes
KW  - photons
KW  - positron emission tomography
KW  - signal to noise ratio
KW  - super ultraviolet
KW  - thyroid carcinomas
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-96863
ER  -