Respiratory liver motion simulator for validating image-guided systems ex-vivo

Abstract

Objective: A clinically realistic phantom incorporating respiratory motion was developed for validating image-guided systems for the liver. Materials and methods: The respiratory liver motion simulator consists of a physical human torso model which allows for an explanted human or porcine liver to be mounted adjacent to an artificial diaphragm. The apparatus can be connected to a lung ventilator for simulation of respiratory motion and is compatible with computed tomography (CT) and magnetic resonance imaging (MRI). To analyze the liver movement generated by the simulator, we examined three porcine livers mounted to the phantom and monitored their movement with a set of optically tracked fiducial needles. Results: Mean displacement between expiration and inspiration was 15.0 ± 4.7 mm, with craniocaudal movement making up the main part (14.2 ± 4.9 mm). In addition, the livers showed movement due to tissue deformation. Conclusion: The liver movement generated by the motion simulator is comparable to that of a human liver in vivo. The phantom thus provides a low-cost alternative to animal experiments for validating image-guided systems.

Dynamic phantom with heart, lung, and blood motion for initial validation of MRI techniques

“…Chang et al (9) constructed a lung phantom that incorporates respiratory motion; however, in this case the phantom consists only of a lung—the heart and circulatory system were absent. Other phantoms (10) have also simulated the effects of respiratory motion; however, the effects of cardiac motion were not modeled. The closest commercially available phantom is a dynamic multimodality heart phantom (Shelley Medical, London, ON, Canada).…”

IJCARS special issue: BVM 2007 German conference on medical image processing

“…Therefore, the contributions in this issue can reflect only some of them. Nevertheless, a number of core areas are addressed: acquisition [1], registration and fusion [3,5], visualization and simulation [6], validation [4], and segmentation [2]. Primary application areas for the new or enhanced methods range from general improvements for an entire class of imaging devices or tasks [1,3], to the support of either the diagnosis and treatment planning [2,6], or the intervention [4,5], for different medical specialties (vascular diseases, abdominal and cardiac surgery, neurology and neurosurgery).…”

“…With their exactly defined and known geometry they provide the assessment baseline within the validation procedures. In Maier-Hein et al [4] a new radiologic phantom for the simulation of respiratory liver motion is presented which can be used for the validation of image-guided liver surgery systems.…”

Real-time movement compensation for synchronous robotic HIFU surgery

“…Anthropomorphic simulation of the liver and diaphragm has been done ex-vivo [6] to simulate the respiration induced movement. This approach uses a ventilator to provide the respiratory movement.…”

“…Due to the subject specific nature and large variation in organ movement, generic movement models are not common. However simplified one dimensional movement models have been used for the liver during radiation therapy [6].…”