@article {Cachovan338, author = {Michal Cachovan and Alexander Hans Vija and Joachim Hornegger and Torsten Kuwert}, title = {Quantitative bone SPECT with a novel multimodal reconstruction}, volume = {54}, number = {supplement 2}, pages = {338--338}, year = {2013}, publisher = {Society of Nuclear Medicine}, abstract = {338 Objectives A new, truly hybrid multimodal reconstruction method has been developed that enables High-Definition Bone and Quantitative-SPECT imaging (HD-Bone, Q-SPECT; Siemens Healthcare). The aim of this study is to compare bone tracer activity concentration (AC) provided by Q-SPECT/HD-Bone (QHDB) with OSEM-based Flash3D (F3D), which is in clinical use. Methods Eight female patients (64.25 {\textpm} 17.94 y; injected dose 537 {\textpm} 82 MBq) underwent a SPECT/CT scan of the lumbar region 4 hours {\textpm} 30 minutes post injection of Tc-99m-diphosphonate. The Siemens Symbia SPECT/CT system used was cross calibrated against our well counter. Images were reconstructed with both F3D and QHDB. Both algorithms use 3D resolution recovery, scatter and CT-based attenuation correction. However, QHDB utilizes a more accurate system model than F3D and reports AC in units of Bq/ml in contrast to counts reported by F3D. The conversion method to convert F3D data to Bq/ml is described in [1]. AC and CT tissue density in Hounsfield Units (HU) were collected in VOIs drawn over the three lower lumbar vertebrae. In addition, standardized uptake values (SUV) were computed. Together, 21 healthy vertebrae, diagnosed free of focal SPECT and CT pathology, were selected. Results The average AC for F3D was 51.87 {\textpm} 17.38 kBq/ml (95 \% confidence interval (CI) 44.00-59.74 kBq/ml) corresponding to an average SUV of 6.41 {\textpm} 1.71 (95 \% CI 5.63-7.18 SUV). QHDB results showed an average activity of 56.70 {\textpm} 17.21 kBq/ml (95 \% CI 48.87-64.53 kBq/ml) and an average SUV of 7.02 {\textpm} 1.67 (95 \% CI 6.26-7.78 SUV). For both reconstructions SUV correlated significantly with HU (F3D: r=0.536, p\<0.05; QHDB: r=0.643, p\<0.005). Both F3D and QHDB AC values correlated significantly (r=0.967, p\<0.0001). Conclusions The results show a high correlation between Flash3D and quantitative HD-Bone with regard to the measurement of regional AC. Tracer uptake correlated with bone density which underlines the physiological significance of this variable. Our data suggest that quantitative HD-Bone can be utilized for quantitative bone SPECT.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/54/supplement_2/338}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }