PT  - JOURNAL ARTICLE
AU  - Einat Even-Sapir
AU  - Bella Yuzefovich
AU  - Elka Miller
AU  - Jean-Paul Bouhnik
AU  - Osnat Zak
AU  - Hedva Lerman
AU  - Genady Lievshitz
AU  - Charles Levin
TI  - Coincidence Imaging Using 2 Dual-Head γ-Camera Systems, With and Without Attenuation Correction
DP  - 2004 Dec 01
TA  - Journal of Nuclear Medicine Technology
PG  - 190--197
VI  - 32
IP  - 4
4099  - http://tech.snmjournals.org/content/32/4/190.short
4100  - http://tech.snmjournals.org/content/32/4/190.full
SO  - J. Nucl. Med. Technol.2004 Dec 01; 32
AB  - Objective: Coincidence imaging enhances the potential for imaging a greater number of patients with 18F-FDG in centers that do not have dedicated PET systems. The purpose of this study was to compare, in a clinical setting, coincidence imaging for tumor detection using 2 dual-head γ-camera systems, one equipped with a 5/8-in. (16 mm) detector (CoDe5) and the other equipped with a newly designed 1-in. (25.4 mm) detector (CoDe8) with an x-ray tube installed in its gantry. Methods: Thirty consecutive patients were studied by both systems during the same visit and had 4 image sets for comparison: CoDe5 without attenuation correction (CoDe5NC), CoDe8 with (CoDe8AC) and without (CoDe8NC) attenuation correction, and fused coincidence-CT images. The target-to-background ratio (T/Bg ratio) and target-to-nontarget ratio (T/NT ratio) were calculated for each tumor site. Results: On visual assessment, 61 tumor sites were detected on CoDe8AC images. Of these, 59 (97%) were detected on CoDe8NC and 54 (88%) were detected on CoDe5NC images. Fused images improved image interpretation in 10 patients (33%) compared with coincidence images alone. Data added by fusion were of clinical relevance in 6 patients (20%). On quantitative assessment, the number of accepted events by the CoDe8 was significantly higher than that by CoDe5 (5.21 ± 1.46 million vs. 1.27 ± 0.36 million, P < 0.001). When comparing CoDe5 with CoDe8 images without attenuation correction, the T/Bg and T/NT ratios were significantly higher on the CoDe8 images (P < 0.0005 and P < 0.0005, respectively). When comparing CoDe8 images with and without attenuation correction, the T/Bg ratio was better on the attenuation-corrected images (P < 0.0005). Conclusion: Coincidence imaging with 1-in. detectors and attenuation correction improve image quality and, to a lesser extent, the tumor detection rate compared with the 5/8-in. detectors and noncorrected images. The data added by fusion of coincidence images to CT findings were clinically relevant in 20% of the patients.