Subject(s)
Brain Neoplasms/etiology , Electromagnetic Fields/adverse effects , Herbicides/adverse effects , Leukemia, Radiation-Induced/etiology , Leukemia/chemically induced , Phenoxyacetates/adverse effects , Brain Neoplasms/chemically induced , Female , Humans , Male , Neoplasms, Radiation-Induced/etiology , Power Plants , Risk Factors , SwedenABSTRACT
Following the legislation for radiation protection in Europe, increasing interest has been given to patient dosimetry in diagnostic radiology. Dose comparisons between groups of patients have demonstrated considerable discrepancies. The equipment, as well as the procedures used, have been scrutinized in order to find the reasons for the variation and to reduce it. In this work, patient size and shape are considered in patient dose evaluations in diagnostic radiology. The size, shape and constitution of the patients are shown to relate exponentially to the energy imparted during examination of the trunk. The equivalent cylindrical diameter of the patient body is used as the independent variable. Exponential functions are created by linear regression. The ICRP Reference Man with an equivalent diameter of 22.9 cm is used as a body-size standard. A method is suggested by which coordinate transformations reduce data to a base line defined by the Reference Man. It is shown that the method reduces the range of energy imparted by between 30% and 60% for six common X-ray examinations of the trunk. Resulting data constitute a finer instrument for intercomparisons between hospitals for the same examination. Further, it is suggested that adipose tissues should not be included when detrimental effects of radiologic exposure are determined. The Reference Man, stripped of 10 kg subcutaneous adipose tissue, is used as the non-fat standard dimension corresponding to the equivalent cylindrical diameter 21.2 cm. The suggested method is used to estimate the fraction of energy imparted to vital organs only. The results show that the energy imparted is reduced by between 30% and 60% according to this model. Consequently, predicted deaths are reduced by the same amount.
Subject(s)
Anthropometry , Radiation Dosage , Radiology , Adipose Tissue , Body Height , Body Weight , Humans , Radiometry , Reference ValuesABSTRACT
The clinical applications of continuous cylindrical TL dosemeters, readout by linear motion through a heated oven, are presented in this work. The applications extend over high energy electron and photon therapy as well as diagnostic X-ray radiology.
Subject(s)
Radiation Protection/methods , Radiography/instrumentation , Radiotherapy Dosage/instrumentation , Thermoluminescent Dosimetry/instrumentation , Brachytherapy/adverse effects , Brachytherapy/instrumentation , Calibration , Fast Neutrons/adverse effects , Humans , Neoplasms/radiotherapy , Radiation Dosage , Radiography/methods , Radiotherapy Dosage/methodsABSTRACT
A method has been developed for the design of flattening filters on the basis of in-vivo oesophagus measurements of absorbed dose distribution in patients given external radiation therapy. The measurements were made by means of LiF-Teflon thermoluminescent dosimeters, read out by an automatic TL-system. A single filter was designed from the resultant dose distribution of parallel opposing fields. The method was checked clinically and was found to be convenient and reliable. The filters reduced the dose variation along the midline of the patients undergoing upper mantle treatments from about +/- 20% to about +/- 5%. The same limits of variation are believed to exist through the entire mid-plane of the body, though it was not possible to prove this by direct measurements.
