Measurement of the dose components of fast and thermal neutrons and photons from a 0.1 mg 252Cf source in water for brachytherapy treatment planning.

The use of 252Cf in brachytherapy is expected to be more effective with the therapy of bulky tumors than the conventional therapy with photons. For treatment planning a code developed for calculation of gamma dose was used to generate the dose distributions of fast and 10B enhanced thermal neutrons and photons. Dose distributions of these components measured with ionization chambers and a GM counter were fitted to analytical functions as required by the modified treatment planning program. A comparison of these experimental results and the treatment planning output indicate good agreement. Therefore, the program may be used to optimize the brachytherapy procedure considering all three dose components. A realistic case of a patient being treated with conventional brachytherapy has been used to calculate the dose distribution that would be obtained by use of the 252Cf source.