1""!!Stereotactic Radiosurgery Head Frame Holder 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 Linear Accelerators……………………………………………………………………5 Head Frame Attachment………………………………………………………………5 Problem Statement…………………………………………………………………….5 Problem Overview…………………………………………………………………….5 Problem Motivation…………………………………………………………………...6 Design Constraints……………………………………………………………………6 Current Devices……………………………………………………………………….7 Competition…………………………………………………………...………………7 Potential Designs…………………………………………………………………...…………7 Dental Light Arm……………………………………………………………………..7 Sliding Wall Arm……………………………………………………………………..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 Future Work and conclusions……………………………………………………………….12 Appendices References…………………………………………………………………………...A Product Design Specifications………………………………………………………B3"" 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 cause harm to the patient. 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 height scale and will translate horizontally, vertically and rotate to adjust for any angle of recline. The mechanism will lock into place at the location where the physician will secure the halo. The halo will be attached to the device via clamps. This device will allow the halo to be safely attached to the 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. Straightforward use and patient safety can be better handled with a rigid device that has locking joints. We propose a Figure 1: Brain scan as used to map the brain in stereotactic radiosurgery. http://www.physics.ubc.ca/research/images/RadTherapy.jpg4""universal device, capable of fitting any patient, which can be used in conjunction with a reclined wheelchair. 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 eventually ceases to exist. These procedures are generally given in a single session, as one dose of highly localized radiation is 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 conical, t-bolt screws to the patients head. The patient is locally anesthetized while the four 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 relative to the head frame can be plotted. The third stage, computerized dose planning, involves the physicians devising a plan to attack the tumor using the patient’s past MRI scans and the CT scan that was taken in phase 2. The fourth and final stage is radiation delivery. There are many machines that are capable of administering this type of radiation, but our client uses a linear particle accelerator, Linac. The patient is conscious and able to communicate with the oncologist during the entire procedure to alert the physician to any pain they may be feeling. Stereotactic radiosurgery and the use of the Linac is not a painful procedure, but at times may feel uncomfortable. This Figure 2. Linear Accelerator used in Stereotactic Radiosurgery
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