Microfocus X-ray imaging of the internal geometry of brachytherapy seeds

• The internal geometry of brachytherapy seeds was evaluated nondestructively.
• A novel microfocus X-ray imaging method was used for the first time for this purpose.
• The two 125I seed models commercially available in Japan were evaluated.
• The microfocus X-ray imaging method was found to be useful for this purpose.
• Geometrical size parameters were obtained for the two seed models.

Precise and reliable geometrical data on the internal structure of seeds are indispensable for dosimetric calculation in brachytherapy. We used a novel microfocus X-ray imaging technique for observing the internal structure of brachytherapy seeds. Two popular 125I seed models were evaluated. Obtained high precision images enabled us to observe the internal structure of seeds qualitatively. Geometrical size parameters were evaluated quantitatively with uncertainty of 0.01–0.04 mm (k=2).