The effect of CT-MR image registration on target volume delineation and dose distribution in radiotherapy planning of brain tumors

METHODS

First, calibration data of the CT was reviewed. Following
image registration, done using four anatomic landmarks,
deliniation of eyeballs and target volume took place.

RESULTS

The registration score was 9.51±0.11 out of 10 and mean distance
was 1.92±0.51 mm. Center coordinates of the eyeballs,
contoured using MRI and CT images were compared. Maximum
difference was 2.25 mm for the right eye and 2.11 mm
for the left eye. Volumes of tumor contours produced from
registered images were bigger (75.37 cm³ vs. 44.81 cm³). But
in the treatment plans without image registration, the tumor
volume received 95-107% of presicribed dose.

CONCLUSION

Image registration process found to be applicable and reproducable
for our clinic. It has seen that image registration improves
target volume delineation.

Keywords: Computed tomography; image registration; magnetic resonance imaging; radiotherapy