Reproducibility and geometric accuracy of the Fixster system during hypofractionated stereotactic radiotherapy.
BACKGROUND
Hypofractionated radiotherapy has been used for the treatment of AVMs and brain metastases. Hypofractionation necessitates the use of a relocatable stereotactic frame that has to be applied on several occasions. The stereotactic frame needs to have a high degree of reproducibility, and patient positioning is crucial to achieve a high accuracy of the treatment.


METHODS
In this study we have, by radiological means, evaluated the reproducibility of the isocenter in consecutive treatment sessions using the Fixster frame. Deviations in the X, Y and Z-axis were measured in 10 patients treated with hypofractionated radiotherapy.


RESULTS
The mean deviation in the X-axis was 0.4 mm (range -2.1 - 2.1, median 0.7 mm) and in the Y-axis -0.3 mm (range -1.4 - 0.7, median -0.2 mm). The mean deviation in the Z-axis was -0.6 (range -1.4 - 1.4, median 0.0 mm).


CONCLUSIONS
There is a high degree of reproducibility of the isocenter during successive treatment sessions with HCSRT using the Fixster frame for stereotactic targeting. The high reducibility enables a safe treatment using hypofractionated stereotactic radiotherapy.
Department of Neurosurgery, Umeå University Hospital, Umeå, Sweden. peter_lindvall_nkk@hotmail.com
Peter
P
Lindvall
Per
P
Bergström
Per-Olov
PO
Löfroth
Roger
R
Henriksson
A Tommy
AT
Bergenheim
D001932:Brain Neoplasms / Q000556:secondary* / Q000601:surgery*; D019583:Dose Fractionation, Radiation; D006801:Humans; D016634:Radiosurgery / Q000379:methods*; D015203:Reproducibility of Results