In SPECT images truncation artefacts may occur when the object does not remain in the field of view (FOV). This truncation may lead to distortions in the transmission map (μ map), which would affect the attenuation correction (AC) and possibly the final image. Our aim was to investigate this distortion on our dedicated small FOV cardiac camera and evaluate the efficacy of the truncation correction.
Using a phantom, transmission data were acquired with our cardiac camera using arrays of 153Gd sources. The width of the phantom was varied by adding attenuating material. AC and non-AC images were analysed.
The results showed that distorted µ maps were produced, which remained distorted even after the application of correction algorithms for chest width measurements greater than 43±1 cm. This distortion was observed to worsen with increasing chest width measurements. Artefacts were not seen for chest width measurements smaller than 43 cm, even when significant anterior attenuation was modelled.
Our findings demonstrate that AC-corrected images acquired with our dedicated small FOV cardiac camera are not suitable for patients with chest width measurements greater than 43 cm.
aDepartment of Medical Physics, Northampton General Hospital NHS Trust, Northampton
bDepartment of Medical Physics, University Hospitals of Leicester NHS Trust, Leicester
cDepartment of Oncology, University of Cambridge, Cambridge, UK
Data were presented previously at the BNMS annual meeting 2011 and published as an abstract in Nucl Med Commum 32(5):426–455, May 2011
Correspondence to Stacey McGowan, BSc, MSc, Department of Medical Physics, Box 152, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ UK Tel: +44 1223 216 472; fax: +44 1223 257 137; e-mail: email@example.com
Received May 21, 2012
Accepted August 29, 2012