Dose verification to cochlea during gamma knife radiosurgery of the internal auditory canal using ionization chamber and diode and mirco diamond detectors.

Warsaw Medical Physics Meeting 2015

Our aim in this study was to verify the absorbed dose to cochlea of the treatment planning system (TPS) during gamma knife radiosurgery of acoustic schwannoma using ionization chamber, diode measurements and a micro diamont detector. The cochlea is a high risk organ which will be saved by treatments of acustic schwannomas by the Gamma Knife radiosurgery unit. Materials and Methods: A human cadaver head and an Alderson phantom were prepared by drilling a hole of 8 mm diameter to the cochlea to place a small-sized detectors to measure the absorbed dose to cochela during gamma knife radiosurgery. CT and Angiography scans of the head phantom were used to check the correct placement of the reference point of the detectors to the cochlea in comparison to the sensitive volume of the different detector types. Treatment plans for earlier internal acoustic schwannoma were transferred to the phantom. Dose points inside the cochlea were derived by TPS. The internal auditory canal with the inserted detector was irradiated to measure the absorbed dose to cochlea. Result: We found a maximum deviation of 30% between TPS calculated and measured dose to cochlea. Conclusion: By the measured dose values were found a wide variation with the dose values calculated using the TPS.
Adolf Ertl, MAS,
Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria
Christian Hranitzky, MAS,
Radiation Protection Dosimetry, 2444 Seibersdorf Laboratories GmbH, Austria
Wolfgang J. Weninger, M.D.,
Centre for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
Brigitte Gatterbauer, M.D.,
Department of Neurosurgery, Medical University of Vienna, 1090 Vienna, Austria

Ertl Adolf

Practical Info

Date
15-05-2015 09:40
Duration
25 minutes 12 seconds
Location