PET/CT Imaging Techniques, Considerations, and Artifacts

Abstract

In the past few years, positron emission tomography/computed tomography (PET/CT) imaging has increasingly been used for the diagnosis, staging, and restaging of malignant diseases. The success of this emerging modality has primarily been due to its ability to combine the advantages of both PET and CT imaging while minimizing their separate weaknesses. The aim of this paper is to provide an overview of the basis behind PET/CT imaging, its advantages, and discuss its imaging artifacts with special emphasis on proposed correction techniques. A brief discussion regarding the use of PET/CT imaging for radiation treatment planning is also presented.

Simultaneous PET–MRI in oncology: a solution looking for a problem?

“…Additionally, PET-CT is not without its limitations. These include radiation exposure associated with the CT component of the examination, artifacts due to CT-based attenuation correction (which are extrapolated from lower energy data) [15], motion in the time interval between the PET and CT acquisitions [16-18], and the not insignificant effects of iodine-based CT contrast agents on the quantification of PET data (summarized in [15]). Finally, MRI also offers a range of relevant, quantitative information on tumor biology related to, for example, blood flow, vascular and tissue spaces, pH and hypoxia, cellularity, and ( via magnetic resonance spectroscopy) metabolite concentrations—all without exposing the patient to ionizing radiation.…”

PET/CT image fusion error due to urinary bladder filling changes: consequence and correction

“…Mismatching of breathing patterns in PET/CT examinations has been previously described as a source of image fusion artifacts [3]. This well-recognized artifact may frequently introduce an image discrepancy in the chest, diaphragm and upper abdominal structures position between the CT and PET images [6,7]. Previous investigators also found pelvic assessment in PET/CT to be challenging due to variable degrees of change in pelvic organs position between PET and CT images [1]; yet, this is the first study that attempts to quantify and address this particular problem.…”

“…Although PET/CT offers many advantages, this dualmodality imaging also poses some challenges, as image registration artifacts may be generated, of which respiratory motion artifact has been well acknowledged in the literature [1][2][3][4][5][6][7][8][9]. We have frequently observed considerable variation in the urinary bladder (UB) shape between CT and PET in the integrated PET/CT images, which can potentially affect the location of pelvic structures in the fused images.…”

Rationale, Instrumental Accuracy, and Challenges of PET Quantification for Tumor Segmentation in Radiation Treatment Planning

“…The attenuation correction (AC) (Zaidi & Hasegawa, 2003) may cause inaccuracies (Mawlawi et al, 2006) due to:…”