title: [Determination of radioactivity by smartphones].
abstract: The interest in the detection of radioactive materials has strongly increased after the accident in the nuclear power plant Fukushima and has led to a bottleneck of suitable measuring instruments. Smartphones equipped with a commercially available software tool could be used for dose rate measurements following a calibration according to the specific camera module.
  
  
  OBJECTIVE
  We examined whether such measurements provide reliable data for typical activities and radionuclides in nuclear medicine.
  
  
  METHODS
  For the nuclides 99mTc (10 - 1000 MBq), 131I (3.7 - 1800 MBq, therapy capsule) and 68Ga (50 - 600 MBq) radioactivity with defined geometry in different distances was measured. The smartphones Milestone Droid 1 (Motorola) and HTC Desire (HTC Corporation) were compared with the standard instruments AD6 (automess) and DoseGUARD (AEA Technology).
  
  
  RESULTS
  Measurements with the smartphones and the other devices show a good agreement: linear signal increase with rising activity and dose rate. The long time measurement (131I, 729 MBq, 0.5 m, 60 min) demonstrates a considerably higher variation (by 20%) of the measured smartphone data values compared with the AD6. For low dose rates (< 1 µGy/h), the sensitivity decreases so that measurements of e. g. the natural radiation exposure do not lead to valid results. The calibration of the camera responsivity for the smartphone has a big influence on the results caused by the small detector surface of the camera semiconductor.
  
  
  CONCLUSIONS
  With commercial software the camera module of a smartphone can be used for the measurement of radioactivity. Dose rates resulting from typical nuclear medicine procedures can be measured reliably (e. g., dismissal dose after radioiodine therapy). The signal shows a high correlation to measured values of conventional dose measurement devices.
authors.affiliation: Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Carl Gustav Carus, an der Technischen Universität Dresden, Fetscherstraße 74, 01307 Dresden. holger.hartmann@uniklinikum-dresden.de
authors.forename: H
authors.initials: H
authors.lastname: Hartmann
authors.forename: R
authors.initials: R
authors.lastname: Freudenberg
authors.forename: M
authors.initials: M
authors.lastname: Andreeff
authors.forename: J
authors.initials: J
authors.lastname: Kotzerke
mesh_terms: D040421:Cell Phone; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008838:Microcomputers; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation*; D012984:Software; D012986:Software Validation