IXSI safety study

Radioembolisation is a clinically accepted oncological treatment for unresectable liver tumours. It involves x-ray and nuclear imaging guided injection of radioactive microspheres into the hepatic artery through a catheter. Current clinical protocol, as advised by the vendors of the microspheres, involves a pretreatment safety procedure using 99mTc-MAA particles, that are injected at the intended therapy location during an extra procedure prior to the therapy procedure. After this pretreatment procedure, but before the start of the therapy, diagnostic nuclear scintigraphy and a SPECT/CT are acquired to rule out excessive lung shunting, shunting to other organs and to assess microsphere distribution in the liver for dosimetry based therapy planning. For this nuclear imaging the patient is transferred to the nuclear medicine department. Limitations of the current workflow include length of the total treatment, and the inaccuracies introduced by replacing the catheter during treatment in the exact same location as during the pretreatment procedure. Introduction of a novel mobile hybrid C-arm (IXSI), capable of real time x-ray and nuclear imaging and of SPECT/CBCT imaging during the intervention, may shorten the treatment to a single radioembolisation procedure, and ensure the same catheter location during pretreatment and treatment injections. In addition, the availability of hybrid imaging during the intervention may help to optimise treatment by direct dosimetric feedback.

The department of radiology at UMC Utrecht initiated a diagnostic C-arm capable of acquiring simultaneous and real-time x-ray and nuclear images to be used in the intervention room. Innovative aspects include a newly developed dual modality SPECT/CBCT detector that allows for combining x-ray and nuclear imaging in a compact and simultaneous manner and the design of a mechanical mobile gantry that can circle the patient in a close body contouring orbit and that allows for integration in an existing intervention room. Using a non-clinical prototype in phantom studies, it has been demonstrated that it is feasible to acquire simultaneous and real-time nuclear and hybrid images. The desire is to demonstrate the hybrid imaging capabilities of IXSI in an explorative pilot study in the intervention room. The study aims at demonstrating that applying IXSI improves clinical practice.

The primary objective of the study is to establish a safe application of IXSI for obtaining 2D and 3D hybrid images in an interventional setting. To this end, for 12 to 15 selected subjects the 99mTc-MAA scout procedure will be extended by additional scans made by IXSI. Angiographic work-up will be identical to the standard procedure up to the point of 99mTc-MAA injection. Then, 2D imaging of the controlled injection of 99mTc-MAA using IXSI is performed, followed by the acquisition of a SPECT/CBCT of the liver by IXSI.

In addition to radioembolisation, a number of other applications for IXSI are envisioned, including the guidance of sentinel lymph node procedures, guidance of biopsies, and inclusion of functional information during cardiac interventions.

Primary Objective:
The main study parameter is to establish the safety of the use of IXSI in an interventional setting. Safety will be assessed based on the CTCAE methodology. Use of IXSI will be considered safe in the absence of Adverse Device Effects (ADE’s).

Patients will come to the clinic for their regular pretreatment procedure. Angiographic work-up will be identical to the standard procedure up to the point of 99mTc-MAA injection. For the interventions of the IXSI study the patient will spend an additional 30-90 minutes in the angio suite. The 2D and 3D images obtained using IXSI will be examined.

Angiographic work-up will be identical to the standard procedure up to the point of 99mTc-MAA injection. Then, 2D imaging of the controlled injection of 99mTc-MAA using IXSI is performed, followed by the acquisition of a SPECT/CBCT of the liver and lungs by IXSI.