title: [Resolution and sensitivity of a two-dimensional ionisation chamber array (PTW type 10024)].
abstract: The two-dimensional verification of intensity-modulated radiation plans is one of the major requirements for the safe application of this technique. The present study examines the resolution and sensitivity of a two-dimensional ionisation-chamber array (PTW2D-Array, type 10024), which can be used for plan verification instead of films. According to the Shannon-Nyquist theorem, the resolution of the 2D-Array is sufficient for dose distributions with a minimal field size of 2 cm x 2 cm. The minimal field size can be reduced to 1 cm x 1 cm by shifting the array 5 mm in the direction of the MLC movement and by repeating the measurements. The high sensitivity against a monitor decalibration for a single field of a sequence is demonstrated on the basis of an individual case. The minimal threshold for MLC misalignment detected by a chamber of the array is less than 1 mm. Therefore, the resolution capabilities of the 2D-Array are sufficient for most intensity-modulated radiation therapy (IMRT)fields.
authors.affiliation: Pius-Hospital und Carl von Ossietzky Universität, AG Medizinische Strahlenphysik, Oldenburg. bjoern.poppe@uni-oldenburg.de
authors.forename: Björn
authors.initials: B
authors.lastname: Poppe
authors.forename: Zanzem
authors.initials: Z
authors.lastname: Atung
authors.forename: George
authors.initials: G
authors.lastname: Chofor
authors.forename: Arne
authors.initials: A
authors.lastname: Blechschmidt
authors.forename: Armand
authors.initials: A
authors.lastname: Djouguela
authors.forename: Ralf
authors.initials: R
authors.lastname: Kollhoff
authors.forename: Antje
authors.initials: A
authors.lastname: Rubach
authors.forename: Dietrich
authors.initials: D
authors.lastname: Harder
mesh_terms: D006801:Humans; D019047:Phantoms, Imaging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards; D012680:Sensitivity and Specificity