Monitoring of a Diagnostic X-Ray Department

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Abstract
After the Department of Diagnostic Roentgenology of Montefiore Hospital was moved to new quarters, a monitoring program was set up to include that department, the dental department, the Country Sanatorium, and every x-ray machine throughout the hospital. There is as much need for the measurement of the radiation, both direct and stray in diagnostic roentgenology as in radiotherapy. The direct radiation from radiographic equipment is in a way self-limiting, for excessive output will be shown by overexposure of films. In fluoroscopic work, however, there is no obvious indication of the intensity of the radiation. The output at the table or at the surface of the patient may range from 3 r/min. to 120 r/min. (24). Since many machines do not have limiting timers, the patient may be receiving an erythema dose or more during a fluoroscopic examination. It is therefore imperative to know the output of every fluoroscope. Much attention has been given to the radiation to which the patient is exposed, but too little to the amount which is received by the radiologist and other personnel. This includes direct radiation, when the field is not correctly shuttered or centered, and stray radiation from the tube housing and from the patient. Workers with isotopes have been made aware of the danger of stray radiation and have been monitored continuously almost from the start. The radiotherapist is cognizant of the danger and has generally taken steps to be protected. The diagnostic roentgenologist, however, who may receive far more than workers of either of these types, has frequently been remiss in his protection, while other physicians have been thoroughly careless. With the advent of isotopes, instruments have been developed which permit a quick survey of the stray radiation around a given space, such as Geiger counter survey meters and ionization chamber survey meters. Small direct-reading ionization chambers are available which can be worn by the individual and from which he can read the amount of radiation received during any procedure or during any period of time. Film badges, which have been used for years in the form of pennies or clips on dental films, have been perfected so that they can be calibrated for the type of radiation under survey and the stray radiation measured in milliroentgens (mr) by their blackening. Ring films can be worn on the finger, measuring the radiation which penetrates protective gloves. An area survey of the therapy department at the Montefiore Hospital indicated that the stray radiation was less than 4 mr /wk. Film badges worn by the therapy technicians showed less than a measurable amount received in two weeks, which is less than 20 mr. In one of the isotope laboratories of the hospital, the workers received less than the measurable amount, 30 mr/wk., on this type of film. The highest amount received was 100 mr/ wk. In another hospital, where considerable isotope work is being done, the chemist who took care of the “hot” work received an average of 100 mr/wk., while the rest of the personnel received an average of 30 mr/wk. or less.

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