title: Developing high-frequency ultrasound tomography for testicular tumor imaging in rats: an in vitro study.
abstract: OBJECTIVE
  This paper describes a feasibility study for developing a 35-MHz high-frequency ultrasound computed-tomography (HFUCT) system for imaging rat testicles.
  
  
  METHODS
  The performances of two kinds of HFUCT-attenuation and sound-speed UCT-based on transmission and pulse-echo modes were investigated in this study. Experiments were carried out using phantoms and actual rat testicles in vitro. HFUCT images were reconstructed using a filtered backprojection algorithm.
  
  
  RESULTS
  The phantom experimental results indicated that all types of HFUCT can determine the dimensions of a plastic cylinder with a diameter of 500 μm. Compared to sound-speed HFUCT, attenuation HFUCT exhibited a better performance in recognizing a tiny sclerosed region in a gelatin phantom. Therefore, the in vitro testicular experiments were performed using attenuation HFUCT based on transmission and pulse-echo modes. The experimentally measured attenuation coefficient and sound speed for healthy rat testicles were 2.92 ± 0.25 dB/mm and 1537 ± 25 m/s, respectively.
  
  
  CONCLUSIONS
  A homogeneous texture was evident for healthy testicles using both modes. An artificial sclerosed tumor could also be clearly observed using two- and three-dimensional attenuation HFUCT in both modes. However, an object artifact was apparent in pulse-echo mode because of ultrasound beam refraction. All of the obtained experimental results indicate the potential of using HFUCT as a novel tool for monitoring the preclinical responses of testicular tumors in small animals.
authors.affiliation: Department of Biomedical Engineering, National Cheng Kung University, Tainan 701, Taiwan.
authors.forename: Chih-Chung
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Electrical Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan.
authors.forename: Wei-Tsen
authors.initials: WT
authors.lastname: Chen
mesh_terms: D000818:Animals; D007091:Image Processing, Computer-Assisted; D008297:Male; D019047:Phantoms, Imaging; D051381:Rats; D013736:Testicular Neoplasms / Q000000981:diagnostic imaging*; D014054:Tomography / Q000379:methods*; D014463:Ultrasonography