Exhibit 10.84

PHYSICIAN SHARING AGREEMENT

THIS PHYSICIAN SHARING AGREEMENT (this “ Agreement ”) is dated effective as of October 1, 2006 by and between Katin Radiation Therapy, P.A., a Maryland professional corporation (“Katin”), and 21st Century Oncology of Harford County, Maryland LLC, a Maryland limited liability corporation (“LLC”)

WITNESSETH:

WHEREAS, Katin and Edward Kiggundu, M.D. (“Kiggundu”) are parties to a physician employment agreement (the “ Katin Employment Agreement ”), pursuant to which Kiggundu is employed by Katin to perform professional medical services as a radiation oncologist and Katin compensates Kiggundu for such services;

WHEREAS, the compensation paid by Katin to Kiggundu includes an annual Salary and Production Bonus;

WHEREAS, the compensation paid by Katin to Kiggundu is amended effective October 1, 2006 to compensate Kiggundu for services provided at the additional practice locations of LLC (the “Amendment”);

WHEREAS , the Katin Employment Agreement provides that Kiggundu shall provide medical services, on a full-time basis, prim