The expansion of a single point CTV.

<p>The expansion of a single point CTV.</p

The values for spherical and cylindrical concave regions of CTVs.

<p>The values for spherical and cylindrical concave regions of CTVs.</p

The method for calculating the margins for random errors adds up the probability that point O is at any position of the PTV to obtain the probability that point O is inside the PTV.

<p>When point O is at position B, C, or D, part (position B and D) or even all (position C) of the CTV is outside the PTV.</p

To ensure that “95% of the systematic displacements of the CTVs for a population of patients are completely inside the PTVs”, we should only add up the probability that point O is at any position inside the small sphere.

<p>When point O is at any position (A, B, C, or D etc.) inside this small sphere, the CTV is completely inside the PTV.</p

The values for spherical and cylindrical CTVs of different radii.

<p>The values for spherical and cylindrical CTVs of different radii.</p