GantryMate: A Modular MR-Compatible Assistance System for MR-Guided Needle Interventions.

Percutaneous minimally invasive interventions are difficult to perform in closed-bore high-field magnetic resonance systems owing to the limited space between magnet and patient. To enable magnetic resonance-guided needle interventions, we combine a small, patient-mounted assistance system with a real-time instrument tracking sequence based on a phase-only cross-correlation algorithm for marker detection. The assistance system uses 2 movable plates to align an external passive marker with the anatomical target structure. The targeting accuracy is measured in phantom experiments, yielding a precision of 1.7 ± 1.0 mm for target depths up to 38 ± 13 mm. In in vivo experiments, the possibility to track and target static and moving structures is demonstrated.

In-room ultrasound fusion combined with fully compatible 3D-printed holding arm - rethinking interventional MRI.

There is no real need to discuss the potential advantages - mainly the excellent soft tissue contrast, nonionizing radiation, flow, and molecular information - of magnetic resonance imaging (MRI) as an intraoperative diagnosis and therapy system particularly for neurological applications and oncological therapies. Difficult patient access in conventional horizontal-field superconductive magnets, very high investment and operational expenses, and the need for special nonferromagnetic therapy tools have however prevented the widespread use of MRI as imaging and guidance tool for therapy purposes. The interventional use of MRI systems follows for the last 20+ years the strategy to use standard diagnostic systems and add more or less complicated and expensive components (eg, MRI-compatible robotic systems, specially shielded in-room monitors, dedicated tools and devices made from low-susceptibility materials, etc) to overcome the difficulties in the therapy process. We are proposing to rethink that approach using an in-room portable ultrasound (US) system that can be safely operated till 1 m away from the opening of a 3T imaging system. The live US images can be tracked using an optical inside-out approach adding a camera to the US probe in combination with optical reference markers to allow direct fusion with the MRI images inside the MRI suite. This leads to a comfortable US-guided intervention and excellent patient access directly on the MRI patient bed. This was combined with an entirely mechanical MRI-compatible 7 degrees of freedom holding arm concept, which shows that this test environment is a different way to create a cost-efficient and effective setup that combines the advantages of MRI and US by largely avoiding the drawbacks of current interventional MRI concepts.

Semi-robotic 6 degree of freedom positioning for intracranial high precision radiotherapy; first phantom and clinical results.

BACKGROUND: To introduce a novel method of patient positioning for high precision intracranial radiotherapy. METHODS: An infrared(IR)-array, reproducibly attached to the patient via a vacuum-mouthpiece(vMP) and connected to the table via a 6 degree-of-freedom(DoF) mechanical arm serves as positioning and fixation system. After IR-based manual prepositioning to rough treatment position and fixation of the mechanical arm, a cone-beam CT(CBCT) is performed. A robotic 6 DoF treatment couch (HexaPOD) then automatically corrects all remaining translations and rotations. This absolute position of infrared markers at the first fraction acts as reference for the following fractions where patients are manually prepositioned to within +/- 2 mm and +/- 2 degrees of this IR reference position prior to final HexaPOD-based correction; consequently CBCT imaging is only required once at the first treatment fraction.The preclinical feasibility and attainable repositioning accuracy of this method was evaluated on a phantom and human volunteers as was the clinical efficacy on 7 pilot study patients. RESULTS: Phantom and volunteer manual IR-based prepositioning to within +/- 2 mm and +/- 2 degrees in 6 DoF was possible within a mean(+/- SD) of 90 +/- 31 and 56 +/- 22 seconds respectively. Mean phantom translational and rotational precision after 6 DoF corrections by the HexaPOD was 0.2 +/- 0.2 mm and 0.7 +/- 0.8 degrees respectively. For the actual patient collective, the mean 3D vector for inter-treatment repositioning accuracy (n = 102) was 1.6 +/- 0.8 mm while intra-fraction movement (n = 110) was 0.6 +/- 0.4 mm. CONCLUSIONS: This novel semi-automatic 6DoF IR-based system has been shown to compare favourably with existing non-invasive intracranial repeat fixation systems with respect to handling, reproducibility and, more importantly, intra-fraction rigidity. Some advantages are full cranial positioning flexibility for single and fractionated IGRT treatments and possibly increased patient comfort.

Surgical application of a new robotic system for paranasal sinus surgery.

The applicability of a robotic system for fully automated surgical procedures approaching the sphenoid sinus is evaluated. An integrated robotic system, A73, for computer navigation-guided, fully automated, and telemanipulation robotic performance is described. Details of the system comprising newly designed surgical instruments for robotic operations and preoperative planning protocols are provided. Experiments with an operational accuracy of less than 1 mm were followed by surgical tests, in which the results of fully automated and telemanipulation performances on 5 cadaveric heads are seen. The A73 system has been successfully used for a reproducible and accurate resection of the anterior wall of the sphenoid sinus. Therefore, we conclude that this system is suited for further testing toward approaching fully automated and more complex procedures of paranasal surgery.

The patient positioning concept for the planned MedAustron centre.

Especially for ion therapy, efficiency in form of patient throughput is becoming increasingly important, and here, patient positioning in treatment room isocenter is a key aspect. In order to ascertain high quality nonetheless, we suggest an alternative to the rigidly installed couch paradigm in form of real-time patient positioning onhand a ceiling mounted infrared photogrammetric system giving positioning information to a novel treatment couch with 6 degrees of freedom integrated on a rolling platform. All MedAustron treatment planning rooms and even the planning CT are not forseen to have a rigidly installed treatment couch.