title: Using a Motion Sensor-Equipped Smartphone to Facilitate CT-Guided Puncture.
abstract: OBJECTIVE
  To demonstrate the use of "Smart Puncture," a smartphone application to assist conventional CT-guided puncture without CT fluoroscopy, and to describe the advantages of this application.
  
  
  METHODS
  A puncture guideline is displayed by entering the angle into the application. Regardless of the angle at which the device is being held, the motion sensor ensures that the guideline is displayed at the appropriate angle with respect to gravity. The angle of the smartphone's liquid crystal display (LCD) is also detected, preventing needle deflection from the CT slice image. Physicians can perform the puncture procedure by advancing the needle using the guideline while the smartphone is placed adjacent to the patient. In an experimental puncture test using a sponge as a target, the target was punctured at 30°, 50°, and 70° when the device was tilted to 0°, 15°, 30°, and 45°, respectively. The punctured target was then imaged with a CT scan, and the puncture error was measured.
  
  
  RESULTS
  The mean puncture error in the plane parallel to the LCD was less than 2°, irrespective of device tilt. The mean puncture error in the sagittal plane was less than 3° with no device tilt. However, the mean puncture error tended to increase when the tilt was increased.
  
  
  CONCLUSIONS
  This application can transform a smartphone into a valuable tool that is capable of objectively and accurately assisting CT-guided puncture procedures.
authors.affiliation: Department of Radiology, Matsuyama Shimin Hospital, 2-6-5 Ootemachi, Matsuyama, Ehime, 790-0067, Japan. masaaki314@gmail.com.
authors.forename: Masaaki
authors.identifier: http://orcid.org/0000-0002-9017-6282
authors.initials: M
authors.lastname: Hirata
authors.affiliation: Department of Surgery, Matsuyama Shimin Hospital, Matsuyama, Ehime, Japan.
authors.forename: Ryouhei
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: Department of Surgery, Matsuyama Shimin Hospital, Matsuyama, Ehime, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Koyano
authors.affiliation: Department of Radiology, Ehime Prefectural Imabari Hospital, Imabari, Ehime, Japan.
authors.forename: Shigenori
authors.initials: S
authors.lastname: Sugata
authors.affiliation: Department of Radiology, Ehime Prefectural Imabari Hospital, Imabari, Ehime, Japan.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Takeda
authors.affiliation: Department of Radiology, Matsuyama Shimin Hospital, 2-6-5 Ootemachi, Matsuyama, Ehime, 790-0067, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Radiology, Matsuyama Shimin Hospital, 2-6-5 Ootemachi, Matsuyama, Ehime, 790-0067, Japan.
authors.forename: Akihisa
authors.initials: A
authors.lastname: Akamune
authors.affiliation: Department of Radiology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.
authors.forename: Takaharu
authors.initials: T
authors.lastname: Tsuda
authors.affiliation: Department of Radiology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.
authors.forename: Teruhito
authors.initials: T
authors.lastname: Mochizuki
mesh_terms: D000038:Abscess / Q000000981:diagnostic imaging* / Q000628:therapy*; D000328:Adult; D004322:Drainage / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D009038:Motion; D009339:Needles; D011677:Punctures / Q000379:methods; D015641:Radiography, Interventional / Q000379:methods*; D000068997:Smartphone; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: CT-guided puncture; Motion sensor; Smartphone application