A manual Multileaf Collimator for use in Cobalt-60 teletherapy

Multileaf Collimators (MLC) for conforming radiation fields to a target shape have been in use for more than 20 years. [1,2] Due to the dominance of linear accelerators (LINAC) in radiation therapy in the western world over Cobalt-60 (Co-60) teletherapy devices these MLC have always been developed for use in a LINAC or dedicated machines.[3,4,5] Despite the undisputed benefits and predominance of linear accelerators in radiation therapy, currently a total of 2344 Co-60 teletherapy machines [6] are still in use worldwide mostly due to their relatively lower costs, simplicity of design and ease of operation. [3] Special infrastructural requirement such as limited access to electric power and servicing personnel remain present in many institutions in the non-western world. The quest for the application of modern technological advances in Co-60 radiotherapy that are standard in Linac radiotherapy as, for instance, a MLC has been mentioned frequently. [3,4,7,8]. Recent studies of a motorized MLC have been reported [9,10] but not been commercially available to this date.