A facility for testing the effectiveness of high energy neutrons for the treatment of malignant tunors has been constructed at the Fermi National Accelerator Laboratory.I The first neutrons were produced by the bonbardment of 66-4MeV protons on a beryllium target in July, 1975. After physically characterizing the neutron beam and performing preliminary radiobiological experiments, patient treatment started in September, 1976. At the tine of this writing, 52 patients had been treated. A description of this facility is given below.

The Fermilab Neutron Radiotheraphy Facility

This research facility has been treating cancer patients for 2.5 years. The original physical plant, controls and treatment room planning were adequate. Improvements have been natural system evolutions to simplify operations and reduce the time to set-up patients, thus increasing patient throughput. Linac changeover from p's to H-'s nearly trebled the dose rate. During the first half of this period most patients were pilot study cases while in the second half, they were mostly protocol cases. Major problems remaining are: 1. patient accession, and 2. lack of ancillary resources normally found in hospitals. One hundred and thirty patients have been entered into a randomized clinical trial from a group of four hundred and forty entered in the study. Descriptions of system improvements and medical research activities are given.

The Fermilab Cancer Therapy Facility: Status Report after 2.5 Years of Operation

A Neutron Cancer Therapy Facility (CTF) has been installed near the Fermilab 200 MeV proton Linear Accelerator. Sixty-six MeV protons extracted from the Linac are transported to a beryllium target that produces neutrons for patient treatment. A 6800-based microcomputer system, interfaced to the Linac control system, has been used since 1975 to perform the data acquisition and control functions required to operate the facility from the Linac control console. Beginning in March of 1977, routine operation of the facilityfor patient treatment has been done from a local medical control room using a disk-based 6800 system operated from a CRT terminal. This system provides the medical technologist with a display of information and control of parameters necessary for patient treatment, including the accumulation and limits of dose delivered to the patient. A hard copy of treatment parameters is generated for the patient's record following the delivery of each fractional treatment. Because the controlroom microcomputer uses a disk operating system, alternate programs may be loaded from disk and the system used for detector calibration, radiobiology irradiations and even further software development. Details of these two microcomputer systems, the parameters and devices they control and monitor, and the operating experience gained in on-line patient treatment use is presented.

The Microprocessor-Based Control System for the Fermilab Cancer Therapy Facility

Techniques for both hardware and software development of microprocessor systems are discussed. A crossassembler, written for execution on a 16-bit control computer, is used to assemble programs and produce binary output tapes for programming read-only memories. A modular 8-bit microprocessor system has been developed that includes a bus-oriented card file and a group of analog and digital I/O interface cards. This has proved to be a flexible and inexpensive method of implementing a variety of one-of-a-kind microprocessor applications in a laboratory environment.

R. F. Kocanda

Papers

A Method for Implementing Microprocessor-Controlled Systems