title: Determination of half value layers of X-ray equipment using computed radiography imaging plates.
abstract: A method for determining half value layers (HVLs) of inverter-type X-ray equipment using a computed radiography (CR) systems was developed. This method is similar to the traditional method, where the air kerma (K) is measured using an ionization based dosimeter and increasing aluminum (Al) absorber thickness, but utilized an imaging plate (IP) and the sensitivity index (S number) of the CR system as the dosimeter and the dosimeter reading, respectively. The IP and the S number were calibrated using an ionization chamber having traceability to the National Standard Ionization Chamber. A modified version of the S number definition equation K=a × S(-b) was used to translate the S number to K values for X-ray beams produced using tube voltages ranging from 50 to 120 kV and additional Al filtration up to 2.5mm. The coefficient 'a' varied depending on the beam quality, while the coefficient 'b' showed a constant value of 0.991. The HVLs in the range from 1.8 to 5.5mm Al that were obtained with this method were in good agreement with those obtained with the traditional method, as uncertainties were between -7 and 4%. This method can be used to determine the HVLs of inverter-type X-ray equipment within an acceptable accuracy.
authors.affiliation: Radiological Technology Diagnostic Imaging Center, Nagoya Daini Red Cross Hospital, Myoken-cho 2-9, 466-8650 Nagoya, Aichi, Japan. a_eiji@msn.com
authors.forename: Eiji
authors.initials: E
authors.lastname: Ariga
authors.forename: Shigeki
authors.initials: S
authors.lastname: Ito
authors.forename: Shizuhiko
authors.initials: S
authors.lastname: Deji
authors.forename: Takuya
authors.initials: T
authors.lastname: Saze
authors.forename: Kunihide
authors.initials: K
authors.lastname: Nishizawa
mesh_terms: D000042:Absorption; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*