Dr. Leonard Manuel Toonkel, MD

Dr. Leonard Toonkel is the chairman of the department of Radiation Oncology at the Mount Sinai Comprehensive Cancer Center. He earned his bachelor’s degree at the University of Miami and his medical degree at the U.M. Miller School of Medicine, where he completed an internship in internal medicine and residencies in therapeutic radiology and radiotherapy. He also was an American Cancer Society clinical fellow at the M.D. Anderson Cancer Center. Dr. Toonkel’s areas of special interest include breast and prostate cancer and specifically the use of brachytherapy, the practice of placing tiny radiation sources adjacent to or within malignant tissues. Dr. Toonkel was involved in the development of radioactive seed implants for prostate cancer and interstitial implantation of brachytherapy applicators for early breast cancer. He has been an item writer and oral examiner for the American Board of Radiology.