Uses of Therapeutic X-Rays in Medicine

Abstract

Treatment of diseases with x rays began within months of Roentgen's discovery, and within four years x rays were being used successfully for the treatment of skin cancers. Deep-seated cancers began to be treated successfully in the 1920's with the advent of "deep" x-ray units and, especially, once supervoltage therapy machines became available in the 1930's. The 1940's and 1950's saw significant growth of megavoltage therapy, initially with Van de Graaff generators and betatrons, and later with linear accelerators. Linear accelerators became popular during the 1960's and 1970's and, by the 1980's they began to replace 60Co units as the most common form of treatment machine. With high-energy linear accelerators, computerized treatment planning, and ingenious fractionation schemes, modern radiotherapy has become a vital component of cancer treatment.

Medical Physics: Some Recollections in Diagnostic X-ray Imaging and Therapeutic Radiology

“…The employment of physicists in radiation therapy dates back to soon after x-rays were first used for treatment of diseases in the late 1890s and early 1900s (24,25). Physicists were needed because the early x-ray machines required constant nurturing to keep them running reliably and with some consistency in dose delivery.…”

“…Physicists were needed because the early x-ray machines required constant nurturing to keep them running reliably and with some consistency in dose delivery. Many of the early developments in dose specification and measurement were made by physicists, culminating in the establishment of the first unit of "dose," the roentgen, in 1928 (24,25). During this same period, a number of hospitals began to employ physicists to deal with the handling and dosimetry associated with radium and radon brachytherapy.…”

“…Physicists pioneered the introduction into radiation therapy of the Van de Graaf generator in the 1930s, the betatron in the 1940s (Fig 3), and the linear accelerator and the cobalt 60 unit in the 1950s. All of these machines required considerable support by medical physicists (24). Of special concern in these early days was the unreliability of these treatment machines.…”

“…Calculation of only a single dose distribution typically took the entire night. The first commercial treatment planning computers were the RAD 8 and the Artronix PC-12 (Fig 4), with 8-and 12-kbytes of memory, respectively (24,35). These computers were slow and quite unreliable, often needing a "kick-start" in the morning.…”

“…Unfortunately, these were far too few programs to serve all of North America, so on-the-job training had to be sufficient for the vast majority of physicists. Gradually, however, throughout the 1970s and 1980s, graduate medical physics programs began to be established and, in the middle 1980s, the AAPM formed a commission to accredit such educational programs, to be later called the Commission on Accreditation of Medical Physics Educational Programs (CAMPEP) (2,24). CAMPEP sets the standards for good graduate programs and, to date, 10 graduate programs have achieved accreditation in North America.…”