vamg6792@uxa.cso.uiuc.edu (Vincent A Mazzarella) (04/26/91)
I saw something about the following potential neurosurgical technology in a magazine article recently. Does anyone know anything more about it? A patient with a cerebral cancer has an MRI done to image the tumour. A neurosurgeon would then drill a dime-sized hole in the skull and implant a BB-sized neodynium-boron-iron pellet in the dura. (Neodynium-boron-iron is the strongest usable, permanent magnetic material.) The patient would then put his or her head into a helmet made of non-magnetic stainless steel which would house six superconducting magnetic manipulation coils cooled by liquid helium. Two biplanar fluroscopes would be attached to the sides of the helmet for visualization during the procedure. The coils would apply a 0.04 N magnetic force to pull the metal pellet through the brain folds and around critical structures to the tumour bed at a speed of 1 mm/sec. The neurosurgeon would control the direction of the pellet's movement using a joystick connected to the workstation controlling the magnetic coils. The progress of the movement would be monitored by two magnet-resistant, biplanar fluoroscopes taking an image 4 /second. Their output would be superimposed upon sagittal, coronal, and transverse images from the original MRI and displayed on three monitors. When the pellet is in place, e.g. at the site of the tumour, radio waves (microwaves) would be directed at the pellet, causing it to heat to 140 - 150 degrees F, killing surrounding cells within a few mm radius. A potential problem seems to be hemorrhage, from manouevering the pellet's progress through the brain. The rounded shape of the pellet might minimize this possibility. A second problem is the problem of how to assure the margins of the tumour have actually been killed by the hyperthermia from the pellet. Research on this technique is being carried out at the University of Virginia, Charlottesville, and the University of Washington, Seattle. I am interested in knowing the successes of these procedures and how often they have been tried. -- Vincent Mazzarella College of Medicine, Neuroscience Program University of Illinois, Urbana-Champaign e-mail: mazz@vmd.cso.uiuc.edu