Radiation dosimetry was originally developed as a tool to quantify biological effects for use in setting dose limits for radiation protection and to determine accurately the irradiation needed to treat tumors or to prevent from deterministic effects and radiation risks. In this book Thermoluminescence Dosimeters (TLD) used in diagnostic, interventional radiology and radiotherapy were studied in terms of dose measurement, optimisation and radiation risk reduction for patients and staff.This book is intended to describe the measurement radiation dose for both patients and staff during diagnostic and radiation therapy using TLDs. It also describes methods of radiation dose optimization during diagnostic and interventional radiology by measuring the entrance and pripheral doses to thyroid and skin for patients during breast, head and neck and prostate treatments. The use of build up caps constructed from materials with different atomic number enable us to measure high radiation energies with acceptable accuracy. The radiation risk for both patients and staff was also evaluated. Therefore, this book provide new data and ideas for clinical medical physicists and dosimetrists.