An on-line computer graphics terminal for radiotherapy treatment planning.

A programmed graphics terminal has been connected on-line to a large time-shared computer for calculating dose distributions in radiotherapy treatment planning and provides a viable alternative to dedicated systems and batch working. The terminal equipment is based on a mini-computer and includes a function-key devise for outline input, a large-screen refresh oscilloscope for viewing results and an X-Y plotter for hard-copy. Radiotherapy dose computation programs in standard Fortran are stored and run on a large remote computer with graphical interaction at the terminal. External beam programs can calculate dose distributions for most commonly used treatment situations and can compute in off-axis planes. Data input is fully interactive and easy to understnad. Dose distributions are displayed as isodose contours. Advantages of the system include accuracy, speed, ease of use and maintenance, and transferability of the programs between different host computers.