Patent Number: 039716970
Section: summary

BACKGROUND OF THE INVENTION This invention is concerned with the production of high purity radioiodine for thyroid measurements and as a general radionuclide. The invention is particularly directed to the utilization of a heat pipe in the production of radioisotopes using very intense particle accelerators. Radioactive iodine is used for medical diagnostic studies. The isotope .sup.131 I has been used for this purpose because of its availability. The radioisotope .sup.123 I is considered much superior to the .sup.131 I in studies where the amount of radiation exposure to a patient is of prime concern. Because of the shorter half-life and the decay by electron capture, the radiation exposure received by the patient from .sup.123 I is about one-fortieth that of an equal amount of .sup.131 I. .sup.123 I is also superior to .sup.131 I because the gamma ray energy of .sup.123 I is 159 KEV compared to 364 KEV of .sup.131 I. Collimators operate more effectively with this lower energy. Also the collimators used with .sup.123 I are less bulky. A method of .sup.123 I production is disclosed in U.S. Pat. No. 3,694,313. The method disclosed in this patent has been quite successful in terms of freedom from radioactive impurities. However, the method is not capable of handling the power densities involved in using high energy, high current machines. SUMMARY OF THE INVENTION According to the present invention cesium is used both as the working fluid of a heat pipe and as the target material for high energy protons. A spallation reaction produces .sup.123 Xe and many radioactive contaminants which pass from the heat pipe to low temperature traps where the undesirable contaminants are removed. The xenon is held for a period of time sufficient for it to decay to .sup.123 I. OBJECTS OF THE INVENTION It is, therefore, an object of the invention to produce the radioisotope .sup.123 I with high energy particles from very intense particle accelerators. Another object of the invention is to produce .sup.123 I using a heat pipe that is bombarded with high energy particles. These and other objects of te invention will be apparent from the specification which follows and from the drawing wherein like numerals are used throughout to identify like parts.