TY - JOUR T1 - <strong>A systematic evaluation of potential clinical impact of improved image quality from a long axial field of view PET/CT</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 3315 LP - 3315 VL - 63 IS - supplement 2 AU - Sabrina Honoré d'Este AU - Annika Loft AU - Flemming Andersen AU - Kim Francis Andersen AU - Naja Hansen AU - Michala Reichkendler AU - Elisabeth Albrecht-Beste AU - Liselotte Højgaard AU - Barbara Fischer Y1 - 2022/06/01 UR - http://jnm.snmjournals.org/content/63/supplement_2/3315.abstract N2 - 3315 Introduction: Total Body PET (TBP) and long axial field of view (LAFOV) PET are potentially game-changing innovations at the threshold of clinical implementation. The EXPLORER (EXtreme Performance LOng axial REsearch scanneR) consortium launched a 194-cm-long PET/CT scanner (uEXPLORER) in 2018. This was followed by a 106-cm-long PET/CT scanner developed by Siemens (Biograph Vision Quadra PET/CT).&amp;nbsp; Early experience has demonstrated very high sensitivity (by a factor 10 compared to current state of art PET/CT) and signal to noise, suggesting improved image quality and/or enabling ultra-fast or low-dose scanning. A LAFOV PET/CT (Siemens Biograph Vision Quadra) was installed at Rigshospitalet, Copenhagen University Hospital in September 2021 kickstarting a systematic evaluation showing significant improvement of both image quality and noise with longer acquisition time. Whether this improved image quality translate into clinical benefit, i.e. more findings or less equivocal reports remains to be proven and early reports have failed to demonstrate any increase in the number of lesions detected. &amp;nbsp;Methods: The first 30 patients referred for clinical FDG-PET/CT on an indication of malignancy performed on the Siemens Biograph Vision Quadra was included. All patients provided written, informed consent. Following injection of 3MBq/kg 18F-FDG 60 min prior to PET scanning, a diagnostic PET/CT scan was performed with IV contrast. PET data was acquired using a standard clinical protocol of 5i4s, 2 mm Gauss filter, PSF and TOF modeling, scan length on the Quadra is fixed at 106 cm. PET acquisition time was 10 mins. For an evaluation of image quality three observers (A-C) were randomly assigned 10 different scans each with five sets of image reconstructions corresponding to 30, 90, 180, 300 and 600 sec acquisition time. All scans were blinded except for a shortened referral indication. Each observer reported total number of findings for each time point in relation to a pre-made list of organ foci and lymph nodes as well as classification of &amp;ldquo;benign&amp;rdquo;, &amp;ldquo;equivocal&amp;rdquo; or &amp;ldquo;malignant&amp;rdquo;. Observers were nuclear medicine physicians with &gt;7 years of experience. Paired comparisons were done using paired T-test. Fig. 1 illustrates the accumulated total number of findings as a function of acquisition time with 90 seconds considered equal to current clinical practice of PET/CT scans. Results: Accumulated number of findings improved significantly with increasing acquisition time (p&lt;0.0005-0.03), excluding the 180-300 sec paired comparison. The total of accumulated &amp;ldquo;benign&amp;rdquo; findings increased significantly from 30-90 sec and from 90-180 sec acquisition time (p&lt;0.015). However no significant increase in &amp;ldquo;malignant&amp;rdquo; findings (p&lt;0.11-0.25) or decrease in &amp;ldquo;equivocal&amp;rdquo; findings (p&lt;0.19-0.70) were observed. No difference was found between 300-600 sec &amp;ldquo;malignant&amp;rdquo; findings (p=1).Conclusions: Accumulated total findings improved significantly with increasing acquisition time. Further, the benign lymph nodes and organ foci findings improved significantly from 90 sec to 180 sec acquisition time indicating a potential clinical impact in the LAFOV PET/CT from current clinical practice. However, our preliminary results suggest indifference in findings with acquisition time beyond the 180-300 second acquisition. ER -