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  -