EFFICACY OF IODINE URINALYSIS FOR DEMONSTRATING THYROID BURDENS

The loss of radioiodine into the atmosphere during a nuclear accident is one of the major pathways by which the general public may receive a radiation dose. Radioiodine is also widely used in the research and medical communities and presents a chronic problem to the radiation worker. Urinalysis is one of the monitoring techniques recommended for identifying potential thyroid uptakes by most of the organizations involved with radiation protection. However, little exists in the literature outlining the methodology to be used or the efficacy of this monitoring technique.; The research upon which this dissertation was based was designed to assess the efficacy of urinalysis. A review of the applicable kinetic models was done to determine their appropriateness. Computer modeling and graphics were used to assess the variances between the two most appropriate models. A study was done using normal subjects to acquire data to be used to; evaluate the parameters associated with the two models, assess the agreement between the computer predicted outputs and the subject urinary outputs, and evaluate the overall efficacy of iodine urinalysis.; The results of the study indicate that an integral sampling technique is the most accurate for back-calculating thyroid activities. Large errors were noted when urinary outputs were estimated using the standard man technique. An anomaly was noted in the nighttime iodine outputs of three female subjects. The present standard man parameters did not fit the data well. A new set of parameters called adjusted man are proposed.; The study concludes that iodine urinalysis can be efficaciously used to identify thyroid uptakes. The use of a three compartment model and an integral sampling technique appear to produce the smallest error. It is recommended that the present standard man parameters be reviewed in view of apparent changes in dietary iodine intake.