18 g puncture needles

Gun-type ¹²⁵I seed implants (Model-6711) were supplied by Atom-Hitech Limited (HTA Co. Ltd., China). The radioactive particle implantation treatment system (KL-SIRPS-3D) was provided by the Beijing Institute of Medical Science and Technology. The 18 G puncture needles were from Cook Medical, Bloomington, IN, USA. The 16-slice CT scanner was from Siemens, Germany.
¹²⁵I seeds were tested for activity by the nuclear medicine specialist at the hospital, and then packaged into clips and sterilized by autoclaving. The Ag rod with ¹²⁵I was mounted in the titanium tube and sealed at both ends. The length of the rod was 4.50 ± 0.3 mm and the external diameter was 0.80 ± 0.03 mm. The half-life of ¹²⁵I seed was 59.6 days. Electron capture decay is accompanied by characteristic X-rays and internal conversion electrons. The electrons are absorbed by the titanium wall of the sealed ¹²⁵I seed source. The predominant Te-KX characteristic X-rays are 27.4 and 31.4 keV, and γ-rays of 35.5 keV. The tissue penetration of ¹²⁵I was only 1.7 cm.

The ¹²⁵I sealed seed source was provided by Tianjin Saide Biological Pharmaceutical Co., Ltd, China. The Ag rod with ¹²⁵I was mounted in the titanium tube and sealed at both ends. The length of the rod was 4.50 mm and the external diameter was 0.80 mm. The matched peripheral dose was 110 to 140 Gy, and the average energy was 27 to 32 KeV. With an initial activity of 0.8 mCi, a radius of 1.7 cm and a half-life of 59.6 days, when an ¹²⁵I seed was implanted in the lesion, it released continuous low-dose γ-ray and soft X-ray, and 93% to 97% of brachytherapy dose was delivered in 8–10 months. The radioactive particle implantation treatment system was provided by Zhuhai Hokai Medical Instruments Co., Ltd, China. The 18G puncture needles were from Cook Medical, Bloomington, IN, USA. The 64-slice CT scanner was from Siemens, Germany.