PHYSICIAN SHARING AGREEMENT

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, primarily at Katin’s radiation oncology center in Martinsburg, West Virginia;

WHEREAS, Katin has agreed to share the services of Kiggundu with LLC, with Kiggundu’s primary assignment remaining Martinsburg, West Virginia and Kiggundu to also provide services at locations of LLC at 602 South Atwood Road, Suite 105, Bel Air, Maryland and 1200 Brass Mill Road, Suite E, Belcamp, Maryland;

WHEREAS, in connection with its agreement to share the services of Kiggundu with LLC, Katin desires that LLC agree to reimburse Katin for Kiggundu’s compensation directly