title: Strength estimation of a moving 125Iodine source during implantation in brachytherapy: application to linked sources.
abstract: This study sought to demonstrate the feasibility of estimating the source strength during implantation in brachytherapy. The requirement for measuring the strengths of the linked sources was investigated. The utilized sources were (125)I with air kerma strengths of 8.38-8.63 U (μGy m(2) h(-1)). Measurements were performed with a plastic scintillator (80 mm × 50 mm × 20 mm in thickness). For a source-to-source distance of 10.5 mm and at source speeds of up to 200 mm s(-1), a counting time of 10 ms and a detector-to-needle distance of 5 mm were found to be the appropriate measurement conditions. The combined standard uncertainty (CSU) with the coverage factor of 1 (k = 1) was ∼15% when using a grid to decrease the interference by the neighboring sources. Without the grid, the CSU (k = 1) was ∼5%, and an 8% overestimation due to the neighboring sources was found to potentially cause additional uncertainty. In order to improve the accuracy in estimating source strength, it is recommended that the measurment conditions should be optimized by considering the tradeoff between the overestimation due to the neighboring sources and the intensity of the measured value, which influences the random error.
authors.affiliation: Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 16, Chuo-ward, Sapporo Hokkaido 060-8543, Japan tanakaken@sapmed.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Endo
authors.affiliation: Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 16, Chuo-ward, Sapporo Hokkaido 060-8543, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tateoka
authors.affiliation: Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, South 1, West 17, Chuo-ward, Sapporo Hokkaido 060-8556, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Asanuma
authors.affiliation: Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 16, Chuo-ward, Sapporo Hokkaido 060-8543, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Hori
authors.affiliation: Hyogo Ion Beam Medical Center, 1-2-1, Kouto, Shingu, Tatsuno, Hyogo 679-5165, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Takagi
authors.affiliation: Auckland City Hospital, Park Road, Grafton, Auckland 1142, New Zealand.
authors.forename: Gerard
authors.initials: G
authors.lastname: Bengua
authors.affiliation: Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 16, Chuo-ward, Sapporo Hokkaido 060-8543, Japan.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kamo
authors.affiliation: Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, South 1, West 17, Chuo-ward, Sapporo Hokkaido 060-8556, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Sato
authors.affiliation: Division of Radiology and Nuclear Medicine, Sapporo Medical University Hospital, South 1, West 17, Chuo-ward, Sapporo Hokkaido 060-8556, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Takeda
authors.affiliation: Teishin-kai Radiation Therapy Institute, 1-6, North 44, East 8, Higashi-ward, Sapporo, Hokkaido 007-0844, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Hareyama
authors.affiliation: Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 16, Chuo-ward, Sapporo Hokkaido 060-8543, Japan.
authors.forename: Koh-Ichi
authors.initials: K
authors.lastname: Sakata
authors.affiliation: Department of Medicine, Graduate School of Sapporo Medical University, South 1, West 16, Chuo-ward, Sapporo Hokkaido 060-8543, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Takada
mesh_terms: D001918:Brachytherapy / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000706:statistics & numerical data; D012588:Scintillation Counting; D035501:Uncertainty
chemical_list: D007457:Iodine Radioisotopes
keywords: 125I, source strength; brachytherapy; linked source; moving source