A novel respiratory gating method for oncologic positron emission tomography based on bioimpedance approach

Respiratory motion causes loss of image quality and inaccuracy of quantification in oncologic positron emission tomography (PET) imaging. This study introduces a bioimpedance-based gating method for compensation of respiratory motion artefacts.

The bioimpedance-based respiratory gating method was studied parallel to a clinically used respiratory gating method [Real-time Position Management by Varian Medical Systems] in 4D PET/CT acquisition of 9 oncologic patients. The quantitative analysis consisted of the evaluation of tumour SUVpeak, SUVmax and volume. Additionally, target-to-background ratios as well as motion in cranial-caudal and anterior-posterior directions were measured. The evaluation was performed with amplitude- and time-based gating using averaged attenuation correction maps.

Bioimpedance gating resulted in 17.7-18.9 % increase in mean SUVpeak and 20.0-21.4 % decrease in mean volume compared to non-gated images. The maximum motion measured from the bioimpedance-gated images was 19 mm in cranial-caudal direction and 9 mm in anterior-posterior direction.

Bioimpedance-based respiratory gating compensates the adverse effects of motion in oncologic PET imaging.