title: Obtaining location of I-125 seed sources for the prostate brachytherapy.
abstract: Treatment planning for ultrasound-guided transperitoneal I-125 permanent prostatic implants is a time consuming task, because this treatment uses many seeds (e.g. 50-80) and there are many solutions (seed positions) for optimizing the dose distribution. In conventional treatment planning for brachytherapy the locations of sources are usually input into a computer manually with reference to two X-ray films. We use so many sources in this treatment that we can hardly obtain accurate location of each source. That is, the identification of each seed with two X-ray films is very difficult. Even though we can use X-ray CT images for deciding on the source position, there are artifacts due to the high attenuation material. This paper proposes a method for obtaining accurate locations of radioactive sources from some projection data (e.g. RPO 60, 40, 20, LPO 60, 40, 20 and 0 deg.) with a reconstruction method. In our method for obtaining actual source positions we use an iterative image reconstruction technique. The results obtained by experiments with a simple prostate phantom and the RANDO phantom showed that the locations of dummy seeds were accurately decided with a reconstructed image by six or seven projection data.
authors.affiliation: Faculty of Engineering, Hosei Univ., Koganei-shi, Tokyo, 184-8584, Japan. ogawa@k.hosei.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Ogawa
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Nyui
mesh_terms: D001918:Brachytherapy; D006801:Humans; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms; D012639:Seeds; D014057:Tomography, X-Ray Computed