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Focus Area 5: Open-source medical devices (OSMD)

Project: Development of an open-source small animal imaging and therapy system

(Surendra Prajapati; prajapati@wisc.edu) Advisers: Thomas Rockwell Mackie and Robert Jeraj

Fig 1. Design of integrated micro CT/PET/RT system

It is time to work together to design and build better and affordable medical instruments to help medical research. Research labs create medical devices but often incomplete that remains within a small group. Sometimes, same ideas are reinvented again in a different lab. Moreover, some labs have ideas but have no means to bring them forward. To address such issues, an open-source medical devices (OSMD) concept was initiated by the Morgridge Institute for Research (MIR) and the University of Wisconsin-Madison with a goal to collaborate among research groups and companies to develop medical technologies that are affordable and available to research groups around the world. It is a forum for free sharing and development of ideas and existing resources in medical devices in an open-source platform. Interested groups contribute to the projects, and the technology is free to use for everybody. The open-source platform is not only for software but also for hardware and necessary management systems. The first OSMD project is to design an open-source integrated micro-CT/PET/RT system for small animals. A small animal platform is not only important for preclinical research but it provides synergies between basic and clinical sciences. In addition, the system is scalable, versatile and cheaper. It has fewer regulatory obstacles. The ultimate goal is to translate and apply the small animal imaging and therapy system design for human use.

We have developed a preliminary design of the integrated micro-CT/PET/RT system with specifications for the first prototype. A Solidworks model is shown in Fig 1. The first OSMD Conference was held on December 1st, 2011 in Wisconsin Institutes of Discovery in Madison. We have defined most of the engineering requirements for the system, and also divided the project into various sub-projects. This will facilitate to collaborate with interested groups. Details of the conference and the project specifications can be seen at the OSMD website: http://discovery.wisc.edu/osmd

Fig 2. Prototype of a binary micro MLC

I am currently working on a couple sub-projects. One of them is the design of binary micro multi-leaf collimator (bmMLC) for the micro-RT system. The latest prototype of bmMLC is shown in Fig 2. The full prototype will have 20 brass plates (0.5 mm thick) stacked in an interleaved position from each side. Cheap micro-servomotors are used to drive the system where the rotation of the motor pulls the collimator plate (via wire) to open the beam. When motor rotates the other way, the plates go back to closed position with the help of tension springs. All components are designed and fabricated at the Medical Devices lab at Morgridge Institute for Research.

At the meantime, I am updating the WiscPlan treatment planning software (TPS) which was developed in UW-Madison for MV photon and proton beams. We are revising this software to develop the TPS for kV photon beams to be used for micro-RT system. Both kV and MV treatment planning systems will be available as open source software in near future. The OSMD project can only be more exciting ahead.



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