Aug. 2, 2011 — The accurate determination of dose in very small fields poses great challenges for high-precision radiation therapy. With Octavius Detector 1000, which was developed for the dosimetric verification of very small fields, PTW has developed a technology to aid stereotactic body radiation therapy (SBRT) and stereotactic radio surgery (SRS) quality assurance (QA).
The new liquid-filled 2-D ion chamber array combines the advantages of ion chambers and solid state detectors, offering a spatial resolution and field coverage as only known from film measurement. It will be on showcase at the Joint AAPM/COMP Meeting in Vancouver, Canada, July 31 – Aug. 4 2011.
??The Octavius Detector is the first commercially available 2-D flat-panel detector array to employ liquid-filled ionization chambers.
Liquid-filled ionization chambers show an excellent signal-to-noise ratio even for very small volumes. They are thus capable of providing high spatial resolution, which is particularly useful for dose determination in very small radiation fields and high dose gradients as encountered in stereotaxy and radiosurgery. Other than solid state detectors, however, liquid-filled ion chambers have a density very close to water and a superior surface coverage. These particular characteristics put them in the same line with dosimetric films. ??
With 977 liquid-filled ionization chambers, each as small as 2 x 2 x 0.4 mm, and a spatial resolution of only 2.5 mm, the array delivers highly accurate dose measurements for field sizes of less than 1 cm x 1 cm up to 10 cm x 10 cm. It will be available by the end of 2011.??
For more information: www.ptwny.com
October 01, 2026 
