An improved method of implanting cells in the body of a patient includes positioning viable cells on a support structure. One or more blood vessels may be connected with the support structure to provide a flow of blood through the support structure. A support structure may be positioned at any desired location in a patient's body. The support structure may be configured to replace an entire organ or a portion of an organ. An organ or portion of an organ may be removed from a body cells and/or other tissue is removed to leave a collagen matrix support structure having a configuration corresponding to the configuration of the organ or portion of an organ. Alternatively, a synthetic support structure may be formed. The synthetic support structure may have a configuration corresponding to a configuration of an entire organ or only a portion of an organ.