Interventional respiratory motion compensation by simultaneous fluoroscopic and nuclear imaging: a phantom study.

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Interventional Radiology

Background:

• Hybrid c-arm scanners acquire nuclear and fluoroscopic data simultaneously for interventional procedures.
• Patient respiratory motion can degrade nuclear image quality in SPECT/CT imaging.
• Hepatic radioembolization is an interventional procedure where radionuclide administration is guided by fluoroscopy.

Purpose of the Study:

• To develop and quantify the performance of a respiratory motion compensation technique for hybrid c-arm SPECT/CBCT systems.
• To extract motion signals from fluoroscopic projections for gating nuclear counts.
• To evaluate the impact of motion compensation on image quality and quantitative accuracy.

Main Methods:

• Simultaneous acquisition of nuclear counts and fluoroscopic projections using a hybrid c-arm scanner.
• Utilized anthropomorphic phantoms simulating hepatic radioembolization distributions and motion patterns.
• Assessed planar nuclear projections visually and SPECT reconstructions visually and quantitatively (activity recovery).

Main Results:

• Uncompensated nuclear projections were blurry due to motion; compensation yielded sharper images comparable to stationary acquisitions.
• Mean activity recovery error in uncompensated SPECT reconstructions ranged from 11.0% to 15.8%.
• Motion compensation significantly reduced mean activity recovery error to 1.8%-5.2% across different motion variations.

Conclusions:

• A hybrid c-arm scanner can effectively compensate for respiratory motion using fluoroscopic projections.
• Motion compensation enhances planar nuclear projection sharpness and improves quantitative accuracy in SPECT reconstructions.
• This technique is valuable for improving image quality in fluoroscopy-guided radionuclide interventions.