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Exposure contribution from Ti K x rays produced in the titanium capsule of the clinical I‐125 seed
Author(s) -
Kubo Hideo
Publication year - 1985
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.595776
Subject(s) - titanium , materials science , capsule , nuclear medicine , radiochemistry , medicine , chemistry , metallurgy , biology , botany
The iodine‐125 radioactive nuclide produces three intrinsic photons, i.e., the 27.4‐keV tellurium (Te) K α and 31.0‐keV K β x rays, and 35.5‐keV gamma rays. In addition, a silver‐wire‐type seed is known to have silver (Ag) K α and K β x rays as a result of interactions between silver atoms and the intrinsic photons. Since the radioactive iodine‐125 is completely sealed with a 0.05‐mm‐thick titanium capsule, fluorescence x rays from titanium atoms are also expected. This study reports (1) abundance of Ti K x rays at 4.5 keV, (2) contribution to exposure from these photons amounting to approximtely 19% of the total exposure at 1‐cm source‐to‐detector distance (SDD), (3) exposure uncertainties of 23% at 1‐cm SDD when Ti K x rays are excluded, and (4) negligible dose contribution to tissue from these photons.