Calculations of total activity and relative radiolysis product yields for selected photonuclear reaction target systems used for production of clinically useful, short-lived, positron-emitting radionuclides.

The potential performance of certain photonuclear target systems designed to produce short-lived positron emitters for nuclear medicine applications was evaluated. Included were calculations of photonuclear target activity yields, relative radiolysis product yields and relative specific activities of products as a function of photonuclear target shapes, dimensions, spacing from the bremsstrahlung photon source, and the energy of the electron beam using the reactions 12C(gamma,n)11C, 14N(gamma,n)13N, and 16O(gamma,n)15O. Results indicate that substantial activity yields can be achieved in these photonuclear target systems and that specific activity of the product varies widely as a function of the energy of the electron beam used to produce the bremsstrahlung and the included angle from the central beam axis that the photonuclear target occupies. Results indicate that several commercial radiotherapy accelerators appear to have electron beam energy and current capabilities suitable for producing multiple mCi (1 mCi = 3.7 X 10(7) Bq) amounts of the above radionuclides.