RT Journal Article
SR Electronic
T1 Improved reconstruction algorithm resolved low sensitivity of the semiconductor detector in FMISO imaging
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1383
OP 1383
VO 51
IS supplement 2
A1 Kenji Hirata
A1 Wataru Takeuchi
A1 Takuhito Narita
A1 Naoya Hattori
A1 Tohru Shiga
A1 Reiko Usui
A1 Yuichi Morimoto
A1 Yuji Kuge
A1 Nagara Tamaki
YR 2010
UL http://jnm.snmjournals.org/content/51/supplement_2/1383.abstract
AB 1383 Objectives One of the major disadvantages of semiconductor detector is lower sensitivity than conventional scintillators, which may degrade image quality particularly with the tracer showing low accumulation in a target such as F-18 fluoromisonidazole (FMISO), a tracer for hypoxia imaging. Our new semiconductor PET system tried to overcome the limitation by improving a reconstruction algorism and optimizing acquisition time. The purpose of this study was to elucidate whether the new reconstruction software and the scanning protocol can compensate low sensitivity of the detector and produce clinically comparable images to those of conventional scanners. Methods Four hours after injection of 400 MBq of FMISO, 9 glioma patients underwent brain PET scanning using the following two different kinds of scanners in random order in a single day; 1) Siemens HR+, 10 min 3D acquisition with FWHM of 6.4 mm using a Fourier rebinning algorithm, and 2) Hitachi semiconductor PET, 30 min 3D acquisition with FWHM of 2.5 mm using a new reconstruction algorithm by application of the median root prior (MRP) which integrated with a resolution recovery program in the maximum a posteriori (MAP) iterative process. In addition to visual assessment, tumor-to-background ratio (TBR) and uptake volume of the target were compared between the two scanners. Results Six of 9 patients showed positive FMISO uptake in the tumor. Visual assessment of intratumoral tracer accumulation was consistent for both scanners. TBR showed no significant difference between the two scanners (3.36±0.52 vs 3.27±0.67, R2=0.871). Volumetry of FMISO avid lesions showed no significant difference between the 2 scanners (23.8±14.2 ml vs 25.0±16.1 ml, R2=0.969). Conclusions The semiconductor PET provided appreciable images of FMISO avid tumors with no significant difference in TBR or in uptake volume from a conventional scanner. In conclusion, improved reconstruction software and optimized acquisition time successfully resolved low sensitivity of the semiconductor detector