The quality assurance program at K ampersand S

K ampersand S operates the largest and one of the most comprehensive Accredited Dosimetry Calibration Laboratories (ADCLs) in the American Association of Physicists in Medicine (AAPM) secondary laboratory system. It offers calibrations covering energies from Grenz-Ray (0.03-mm Al) to cesium-137 and cobalt-60, brachytherapy source and well chamber calibrations for low-activity sources, and, recently, high-dose-rate iridium-192. The present Quality Assurance (QA) program at K ampersand S began with the AAPM Guidelines for Accreditation (Task Group No. 22 and No. 3, 1989) and grew over the past 10 years to include all aspects of providing a private, self-supporting calibration service from a free-standing independent facility. Some aspects of the QA program were prompted by the requirements of the nuclear power industry while other parts were from national consensus standards or the experiences of staff. Redundancy and teamwork are the most important characteristics of this QA program. K ampersand S has participated in a National Institute of Standards and Technology (NIST) measurement quality assurance (MQA) program since 1982, and, in recent years, an ADCL intralaboratory intercomparison was conducted by Task Group 3 of the Radiation Therapy Committee of the AAPM. One measure of the credibility of a QA program is consistent performance on the MQA program and the ADCL intercomparisons over the past 10 years. An equally important measure of the ability of a program to assure quality results is the frequency of reported errors