This book was produced to answer the need expressed by trainee medical physicists and radiotherapy technologists for clear and detailed description of the verification of light and radiation field in Radiotherapy machines. The importance of this book is to highlight the Sufficiency of the application of image processing methods in the field of radiotherapy machines (Telecobalt and Linear acceralator). In addition to its role to objectively score the alignment of the photon field that is unable to detect by naked eye special in megavoltage machines. Details of the techniques used vary in the image processing programs such as (e.g. Matlab, IDL .etc.) from center to another. Any trainee medical physicists and Radiotherapy technologists will soon learn those variation, but I hope that, using my book and work, sometimes unavoidably, unsupervised, they would be able to produce adequate results of test.