ELSEVIER New Technology HOLOGRAPHIC IMAGING OF HUMAN BRAIN PREPARATIONS-A STEP TOWARD VIRTUAL MEDICINE Kathryn Ko, M.D. and John M. Webster, Ph.D. Division of Neurosurgery, Cornell Uniuersity Medical College New York, New York (IX), Dept. of Physics, University of Portsmouth, UK (JMW); and Holographics, Inc., New York, New York (JMW) Ko K, Webster JM. Holographic imaging of human brain prepa- rations-a step toward virtual medicine. Surg Neural 1995;44: 428-32. BACKGROUND Holography is the only technique that can record the full tri-dimensional quality of an object, and allow the ob- server to easily seethis as an imagethat is truly 3-D. The pulsed laser can capture even a moving object’s three dimensional form as a hologram because of its short wavelength. METHODS Using a modification of the Klinger processing sequence, formalin-fixed human brains were subjected to periods of freezing and thawing. This assisted the visual demarca- tion between white and gray matter during neuroana- tomical dissection. Holographic methodology with the Lumonic HLS2pulsed ruby laser was employed to create three dimensional imagesfrom brain preparations. RESULTS Master holograms of the human brain preparations dem- onstrating the various pathways such as vision, cortico- spinal, etc. are made using the ruby laser at wavelength 694.3 nanometers. From this master an infinite number of holograms can be copied. CONCLUSION By providing immediate three dimensional information, holograms uniquely facilitate the spontaneous under- standing of human neuroanatomical relationships which cannot be as efficiently learned with photographs or di- agrams. This points the way toward future educational and biomedical applications of this emerging technology. KEY WORDS Holography, three dimensions, pulsed ruby laser, human brain preparations. Address reprint requests to: Kathryn Ko, M.D., 1300 York Ave., LC-807, Division of Neurosurgery, Cornell University Medical College New York, New York 10021. Received June 17, 1994; accepted June 27, 1995. 009~3019/95/$15.00 SSDI 0090-3019(95)00304-M D ifferent technologies including computer en- hanced MRI or CT images as well as virtual reality are evolving in the use of three dimensional displays. These current imaging techniques are on the verge of capturing objects as they exist in three dimensions. This eliminates the difficult cognitive translation that is required to transform two dimen- sional information into the full three dimensional reality. One other significant area of development in three dimensionality is holography. Although holo- graphic principles were introduced in 1947 [2,6], and extensive research has ensued since the inven- tion of the laser in 1960 [8], truly practical applica- tions within medicine have yet to be realized. A reliable coherent optical wave derived from the laser is essential to holography and therefore tech- nological progress in this field has been tied to the laser’s evolution [2,6]. With the continuous wave (CW) laser only inanimate structures can be used for holography because even microscopic move- ment, including the heart beat and respiration, ne- gates the image, as do normal environmental dis- turbances such as building vibrations and air currents. Examples of holograms made from a CW laser can be found on credit cards, popular maga- zines and novelty trinkets. Recent refinements in the original 1960s concept of the pulsed wave (PW) laser [8] make it now possible to holographically image previously inap- plicable objects such as humans, in spite of physi- ologic movement. Unlike CW lasers, the PW laser permits the recording of entities under less restric- tive laboratory conditions. For the first time holo- graphic images of human anatomical structures can be made with little more preparation and in com- parable time as the taking of a photograph. Mass produced CW holograms such as those embossed on credit cards are limited in volume 0 1995 by Elsevler Science Inc. 655 Avenue of the Americas, New York, NY 10010