Abstract

Film dosimeters provide two-dimensional measurement with high spatial resolution over a large area. There are, in general, two types of films used as dosimeters: radiographic and radiochromic. Radiographic films have been phased out of most of radiotherapy clinics; radiochromic films are now widely used in radiation therapy dosimetry and particularly in quality assurance (QA), especially for planar dose distribution comparisons. This chapter provides a summary of film-based dosimetry and their basic principles and applications in radiation dosimetry. Furthermore, the history of film, origin and mechanism of response to radiation, factors influencing the film response, applications, and practical examples are also discussed in more details for radiochromic films.