Cerebral arteriovenous malformation (AVM) is one of the most complex, especially life-threatening, vascular pathologies of the patient, occurring in both children and adults. If AVM is formed near functionally important areas of the brain or has a large spread cross-section, the tactic of intravascular AVM embolization with endovascular adhesives may be used in the hope of reducing the risk of bleeding and achieving complete occlusion (success rate 30-62%). Higher treatment efficacy can be achieved applying stereotactic radiosurgery treatment of AVM nidus with a Gamma knife (success rate 68-90%), but the final occlusion occurs only after 1–3 years. The promising complex application of both methods – Gamma knife radiosurgery after vascular embolization – does not give the required result yet, because for an unknown reason the success rate of occlusion becomes lower after this treatment. It was made a hypothesis that the reduced occlusion rate is a result of possible gamma radiation dose redistribution in the target due to the fact that heavy metal Ta compounds are used for imaging during embolization, but there is a lack of experimental data.
In this project, the effects of gamma knife radiation on an “embolized object” will be investigated using innovative in vitro dosimetry methods (3D gel dosimetry, GafChromic films). Experimental studies will be performed using 3D printed vascular models (phantoms) recalling patient‘s anatomical structures that are reconstructed from diagnostic images. These innovative phantoms will be produced from new materials of special composition that meet the principles of the circular economy and are formed using extruder technology, whose physical properties (bioequivalence, gamma photon absorption, elasticity) are close to those of blood vessels. Application of individualized phantoms, innovative dosimetry techniques, and gamma knife technology to perform radiosurgery on complex morphology targets, will allow for evaluation of endovascular embolization-induced changes in gamma radiation distribution in the AVM target, foresee tendencies for these changes and develop knowledge-based recommendations that will contribute increasing the efficacy of the method (embolization + radiosurgery) in the treatment of AVM pathology.
Project funding:
KTU Research and Innovation Fund
Project results:
A model simulating arteriovenous malformation for 3D printing has been reconstructed from real patient computed tomography images (90% compliance factor). A thermoplastic polymer enriched with recycled high-density polyethylene additives for 3D printing of imitation blood vessels, has been created . A new material indicated tissue equivalency and corresponding elasticity as of blood vessels. 3D printed blood vessel models have been used for studying the influence of vascular embolization. Dose gel of modified content has been created for treatment dose measurements. Gel dosimetry method has been developed to evaluate the effect of vascular embolization on the deviations from the planned radiosurgery (Gamma knife technique) doses for a patient.
Project results were published in the journal GELS (Q1) and in the Conf. Proc. of the Int. Conf. ‘Medical Physics in the Baltic States”
Period of project implementation: 2021-04-01 - 2021-12-31
Project partners: Lithuanian University of Health Sciences
