Zeitschrift für klinische und experimentelle Onkologie

Evaluation of Automatic and Manual Contouring of Cranial Structures

Vadim Y Kuperman, Kouskoulas TN, Battle JA, Brad A Factor, Charles D Hechtman, Oscar F Carbonell, Miles DT, Lubich LM, Mendoza AS and Page DB

Evaluation of Automatic and Manual Contouring of Cranial Structures

Objective:

This study evaluates automatic and manual segmentations of cranial structures in iPlan treatment planning system (Brainlab, Munich, Germany).

Methods:

For the analysis of the automatic segmentation algorithm in iPlan, delineations of cranial structures including brainstem, optic nerves, optic chiasm, eyes and eye lenses were analyzed for ten patients with brain metastasis. Five participating radiation oncologists contoured the same structures manually on axial slices of T1-weighted MR scans of the head. The automatic and manual delineations of the cranial structures were compared by using the following quantitative measures: Dice similarity coefficient, differences in the structures’ volumes and positions of the center of mass.

Results:

The comparison of the automatically generated contours and those produced by clinicians, and inter-comparison between clinicians’ delineations indicate relatively good agreement for the brainstem and eyes but unsatisfactory agreement for other structures.

Conclusions:

The obtained results indicate the need for careful verification of the automatically segmented structures in the iPlan treatment planning system. The observed variability between the delineations by different clinicians is of concern. One possible remedy is to utilize expansion margins for the critical cranial structures during treatment planning.