A beam alignment device for matching fields.

When radiation treatment is delivered to adjacent or contiguous tumor volumes with multiple fields, the geometric alignment of the beams is particularly critical. A beam alignment device has been developed that enables precise matching of such fields.

Three-field technique for breast irradiation using tangential field corner blocks.

A further modification of the three-field technique for the radiotherapy of the breast has been developed. Two isocentric opposing tangential fields encompass the breast, chest wall, and may include the internal mammary lymph nodes. The third, an anterior field, encompasses the axilla and supraclavicular areas. As with our previously reported techniques, the objectives of the present modification is to make the posterior edges of the tangential fields coplanar and to match the cephalad geometric edges of the tangential fields to the caudad geometric edge of the supraclavicular field. A half-beam block is used to shield the caudad half of the anterior field, thus producing a vertical transverse plane to which the tangential fields are matched. Small corner blocks are used on the cephalad edges of the tangential fields to produce the vertical edge necessary for matching to the anterior field. It is essential that the match between the tangential fields and the anterior field be geometrically correct to ensure both local control of disease and good cosmetic results. Two advantages of the present technique are the ease with which it can be carried out and the precision of the match plane without the use of cumbersome mechanical accessories.

Quality assurance in stereotactic radiosurgery using a standard linear accelerator.

Methods have recently been developed for using standard linear accelerators to perform stereotactic radiosurgery. The accuracy necessary to perform this procedure requires an intensive quality assurance program to encompass all aspects of dose calibration and mechanical integrity of the treatment unit, the treatment planning process, and treatment delivery. The programs developed at the Joint Center for Radiation Therapy (JCRT) include testing of the linear accelerator and the stereotactic system, cross checking of the treatment planning process, and a quality assurance check list of the treatment delivery procedure. This report outlines in detail the quality assurance program currently in use at the JCRT.

Radiation therapy technologists: a profile.

The shortage of radiation therapy technologists continues to be a national problem. Data regarding the population who enter the profession, as well as the professional expectations and factors leading to job satisfaction of therapy technologists, need to be determined before effective recruitment and retention strategies can be developed. This article details a survey that was conducted to gather this data.

Ethical issues of randomized clinical trials.

Randomized clinical trials are an accepted form of experimentation on human subjects to determine the effectiveness of new treatment regimens or drugs. The Declaration of Helsinki, adopted by the World Medical Association, has established guidelines to safeguard humans used as subjects in medical experimentation. The ethical issues of informed consent, the physician-patient relationship and the potential for abuses in research must be considered prior to agreeing to participate in human experimentation.

Technical consideration of intact breast irradiation.

The "hanging block technique" is an exacting and demanding technique that meets the requirements for dose homogeneity in the treatment volume with maximal sparing of normal tissues. We have found the technique to be reproducible and it appears to avoid the matchline problems associated with the traditional three-field technique.

Ancient technology in contemporary surgery.

Archaeologists have shown that ancient man developed the ability to produce cutting blades of an extreme degree of sharpness from volcanic glass. The finest of these prismatic blades were produced in Mesoamerica about 2,500 years ago. The technique of production of these blades was rediscovered 12 years ago by Dr. Don Crabtree, who suggested possible uses for the blades in modern surgery. Blades produced by Dr. Crabtree have been used in experimental microsurgery with excellent results. Animal experiments have shown the tensile strength of obsidian produced wounds to be equal to or greater than that of wounds produced by steel scalpels after 14 days of healing. We have been able to demonstrate neither flaking of glass blades into the wounds nor any foreign body reaction in healed wounds. Skin incisions in human patients have likewise healed well without complications. The prismatic glass blade is infinitely sharper than a honed steel edge, and these blades can be produced in a wide variety of shapes and sizes. It is therefore suggested that this type of blade may find an appropriate use in special areas of modern surgery.