Measurement of radiation absorbed dose in endovascular Ho-166 brachytherapy using a balloon angio-catheter.
The purpose of this study was to estimate the absorbed dose distribution of Ho-166 endovascular beta irradiation using an angio-catheter. The liquid form of Ho-166 was produced at the Korea Atomic Energy Research Institute (KAERI) by an (n,gamma) reaction. Ho-166 has a half-life of 26.8 h and emits a high-energy beta particle with a maximum energy of 1.85 MeV. GafChromic film was used for the estimation of the absorbed dose of beta particles. A Co-60 teletherapy source and a 6 MV photon beam from a linear accelerator were used to generate dose-optical density calibration curves. The exposed films were read using a videodensitometer. With a modified micrometer, the film was positioned accurately on the surface of the balloon in water. The balloon was filled with Ho-166 solution to a pressure of 4 atm. Several film exposures were made with varying irradiation times and activities. The radiation absorbed dose rates were 1.02, 0.51 and 0.35 Gy x min(-1) x GBq(-1) x ml(-1) at the balloon surface, 0.5 and 1 mm from the balloon surface, respectively. The absorbed dose distribution revealed that Ho-166 is a good source for endovascular irradiation as the beta range is very short, avoiding unnecessary irradiation of normal tissue. A clinically applicable irradiation and duration of exposure were achievable utilizing our system.
Joh
C W
CW
Department of Nuclear Medicine, Ajou University School of Medicine, Suwon, South Korea.
Park
C H
CH
Kang
H J
HJ
Oh
Y T
YT
Chun
Kim
H S
HS
Choi
B I
BI
Park
K B
KB
Kim
Y M
YM
Kim
K H
KH
Vahc
Y W
YW
Jang
J S
JS
Lee
B K
BK
D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D001918:Brachytherapy / Q000379:methods*; D003327:Coronary Disease / Q000532:radiotherapy / Q000628:therapy; D006695:Holmium / Q000627:therapeutic use*; D006801:Humans; D019047:Phantoms, Imaging; D011868:Radioisotopes / Q000627:therapeutic use*; D019275:Radiopharmaceuticals / Q000627:therapeutic use*; D011879:Radiotherapy Dosage
D011868:Radioisotopes; D019275:Radiopharmaceuticals; D006695:Holmium