The most significant effort applying RP to medical modeling, both in number of programs and scope of effort, is in Europe. The major focus is in the BRITE EuRAM PHIDIAS project administered by Materialise, NV (Belgium), an RP service bureau set up in the technology park on the campus of the Catholic University of Leuven. Materialise is developing the CT/MR-to-RP interface software and building the RP models. The project team includes Zeneca Specialties (UK), which is developing new stereolithography resins, and many clinics, hospitals, and university medical research groups.
Other centers focused on surgical applications of RP include: the Institute of Medical Physics at the University of Erlangen-Nürnberg in Erlangen, Germany, where Professor Willi Kalender (developer of the spiral-scan CT) is focused on data interpretation and presentation; the University of Zurich, Switzerland, where Professor Stucki is also studying image analysis and presentation; and the University of Leeds, UK. In addition, there is a significant number of locally funded application evaluations underway throughout Europe, including in France, Austria, Denmark, Italy, and Germany. The major advances in technology have been made in the PHIDIAS project. These include the development of the software that interprets the CT scan data and generates the files needed to build the models by stereolithography; the development of a two-color resin for stereolithography that permits marking the patient's identification into the model and designating the regions of interest; and a survey quantifying the impact of the model when compared with traditional images.
There is also an RP medical work area specialization that is funded through the European Action on RP (EARP). There is some overlap between the work funded through EARP and PHIDIAS. One project in the EARP program that could have a major impact on the acceptance of RP medical models is the EARP Database Project, which is attempting to quantify the cost-benefit of using RP models in terms of dollars saved, surgical hours saved, enhanced patient service, and speeded recovery. One goal is to be able to justify insurance coverage of the model-making procedure. Another database measuring the effectiveness of RP models has been constructed by Smet (1995) as part of the PHIDIAS project. The European projects are sufficiently mature to lead to regular conferences focused on the medical applications areas. These include the biannual International Workshop on Rapid Prototyping in Medicine and the annual PHIDIAS Workshop on Stereolithographic Modelling.
The major program in Japan is focused through INCS, Inc., a Tokyo-based service bureau, and a consortium of six university medical programs. Their main focus is on the creation of models for surgical planning. In addition, INCS is developing software that will provide smoother, more accurate models from the scan data. Its results are not as well publicized as those of the European programs. In addition, there is at least one other project underway, at Hokkaido University, focused on dental implants and tooth repair. INCS has made a cranial implant in ceramic apatite on a multiaxis milling machine. The data was developed using symmetry in the CT-scan data to cover the defect in the skull. The prosthetic was verified by placing it on the RP model of the patient. It was surgically implanted, verifying the accuracy of the procedure. This was done in conjunction with Keio University. Some of the results have been published (Lightman et al. 1995).
The Australian program is directed by a neurosurgeon, Paul D'Urso, MD, PhD (University of Queensland Department of Surgery, Brisbane), who also has expertise in the engineering and computer aspects of RP. The impressive results illustrate the importance of having surgeons pulling the technology rather than engineers pushing it. Dr. D'Urso's surgical team has used RP models in more than 70 surgeries, and they now rely almost exclusively on the RP models, rather than on the CT scan data, for surgeries where RP models apply. D'Urso uses the Materialise software to convert the scan data for stereolithography model fabrication. His focus has been on the use of the models for both surgical planning (Fig. 12.4) and fabrication of surgical tools.
The major effort in the U.S. programs has been the fabrication of hip and knee replacements. By and large, these units are produced in standard configurations and sizes and stocked as commodity items. There has been limited application of the unique RP models needed for reconstruction surgery and similar applications. There are activities ongoing at centers of research such as the University of Dayton (Ohio); Laserform, Inc. (Michigan), which is working in association with Materialise; Bowling Green State University (Ohio); UCLA; and the Prosthodontics Department of the USAF Medical Center, Lackland AFB. Recently, Materialise opened a U.S. office in Michigan. The U.S. effort is small and there is no central coordination at this time, reflective of the federal government funding being focused almost exclusively on telemedicine and CAS.