1""!!Stereotactic Radiosurgery Head Frame Holder December 9, 2009 Client: Lori Hayes, MS RN Advisor: Professor Wally Block Leader: Rebecca Clayman Communicator: Katie Pollock BWIG: Justin Cacciatore BSAC: Bret Olson2""Table of Contents Abstract………………………………………………………………………………………...3 Introduction…………………………………………………………………………………….3 Background………………………………………………………………………………….....4 Stereotactic Radiosurgery……………………………………………………………...4 Linear Accelerators…………………………………………………………………….5 Problem Statement……………………………………………………………………..5 Problem Overview……………………………………………………………………..5 Project Motivation……………………………………………………………………..6 Design Constraints……………………………………………………………………..6 Current Devices………………………………………………………………………..7 Competition…………………………………………………………...……………….7 Potential Designs…………………………………………………………………...………….7 Dental Light Arm……………………………………………………………………...7 Sliding Wall Track…………………………………………………………………….8 A-Frame Wheelchair Attachment……………………………………………………..9 Frame Holder Design Matrix………………………………………………………….9 Attachment of Head Frame…………………………………………………………………...10 Clamps………………………………………………………………………………..10 Magnets……………………………………………………………………………….10 Screws………………………………………………………………………………...11 Final Design…………………………………………………………………………………..12 Testing………………………………………………………………………………………..13 Translation……………………………………………………………………………13 Positioning……………………………………………………………………………14 Physician Testing……………………………………………………………………..14 Future Work…………………………………………………………………………………..15 Head Rest……………………………………………………………………………..15 Incorporation………………………………………………………………………….15 Ethical Considerations………………………………………………………………………..15 Appendices A - References………………………………………………………………………...17 B - Product Design Specifications……………………………………………………193"" Abstract Stereotactic radiosurgery is a precise method of delivering radiation therapy to a patient with a malformation in the brain. At the University of Wisconsin Madison hospital, a linear accelerator is used to focus beams of radiation onto the tumor to damage the DNA so that cells within the tumor are not able to further replicate and metastasize. To map the location of the tumor, the patient wears a head frame known as a halo that is secured by tightening four precision screws into the patient’s head. This procedure currently requires two medical personnel. Our team plans to fabricate a device that holds the halo while a single physician secures it into place. This device will mimic a human set of arms and will translate horizontally, vertically and rotate to adjust for any angle of recline. The mechanism will stabilize at the location where the physician secures the halo. The halo will be attached to the device via clamps. This device will allow the halo to be safely attached to a patient in preparation for stereotactic radiosurgery. Introduction Stereotactic radiosurgery is a non-invasive procedure in which radiation must be precisely delivered to particular areas of the brain (Figure 1). During the procedure, a patient must wear a titanium head frame which is attached by four precision screws to their skull. Currently, our client uses a Velcro strap to stabilize the head frame while local anesthesia is administered and the screws are fastened. The main concern with this method is that it requires the attention of at least two medical personnel. A simpler method of attachment, while maintaining patient safety, can be delivered with a rigid device that has locking joints. We propose a universal device, capable of fitting any patient, which can be used in conjunction with a reclined wheelchair. Figure 1: Brain scan as used to map the brain in stereotactic radiosurgery. http://www.physics.ubc.ca/research/images/RadTherapy.jpg4"" Background Stereotactic Radiosurgery Stereotactic radiosurgery is a non-invasive procedure primarily performed on patients with benign tumors, malignant tumors, or arteriovenous malformations. The objective of this procedure is to precisely deliver high doses of radiation to abnormalities without damaging surrounding brain tissue. The radiation does not destroy the tumor or malformation, but rather damages its DNA so that it can no longer reproduce. A period of months after the treatment, the abnormality shrinks and recedes. These procedures are generally given in a single session, as one dose of highly localized radiation is normally enough to damage the DNA of the malformation. The procedure is a day long process for the patient and involves four phases. Initially, a titanium halo is attached by four conical, t-bolt screws to the patients head. The patient is locally anesthetized while the screws are drilled into the skull. The next phase in the process is imaging. The patient undergoes a CT scan so that the location of the aberration
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