Abstract
Objectives
The aim of the study was to analyze whether the fixation of the stereotactic frame is stable and whether the location of the treated target coincides with its anatomical location during Gamma Knife® surgery (GKS).
Materials and methods
Stereotactic MR examinations using the same high-resolution MRI protocol were performed before and after GKS in 18 consecutive patients. The stereotactic (x,y,z) coordinates for three different anatomical landmarks were independently defined three times in each study for each landmark of the images taken before and after GKS by two of the authors, resulting in a total of 648 coordinate definitions.
Results
The uncertainty in the readings of the coordinates for the anatomical landmarks was of the same magnitude as the difference in the coordinates before and after GKS in all but one patient. The differences in this one case were due to MR distortion and not to repositioning of the frame. The difference in the coordinates before and after treatment was not affected by the removal of one of the frontal fixation screws in one of the patients.
Conclusions
The stereotactic frame position is stable and does not move.
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References
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Conflicts of interest
None.
Disclosure
Bengt Karlsson has served as a consultant for Elekta Instrument AB, Stockholm, Sweden
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Comment
The issue of accuracy, precision, reproducibility and the role of stereotactic frames is frequently the object of unsubstantiated claims, but rarely addressed seriously in the literature.
Thus, Karlsson, Kalend and Martinez have to be congratulated for this important contribution to the field.
Jean Regis
Marseille, France
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Karlsson, B., Kalend, A. & Martinez, R. Frame stability and anatomical QA in radiosurgery. Acta Neurochir 153, 2265–2270 (2011). https://doi.org/10.1007/s00701-011-1067-5
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DOI: https://doi.org/10.1007/s00701-011-1067-5