An Empirical Model for Describing the Small Field Penumbra in Radiation Therapy

<div>(a) The right-side penumbra dose profiles vary with the gantry angles of the second exposure. The curvature of the right-side penumbra region can be fitted using the LSRE model by adjusting the (<i>n</i>) <i>T</i> and (<i>t</i>). (b) The left-side penumbra dose profiles vary with the gantry angles of the second exposure. The curvature of the left-side penumbra region can be fitted using the LSRE model by adjusting the (<i>n</i>) <i>T</i> and (<i>t</i>). The “90° measured curve” and “90° model estimated” curve denote the dose profile measured at the gantry angle of 90° in the ball phantom and the predicted curve at the same. They overlap each other completely.</div>

BioMed Research International

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Figure 5

Figure 5: An Empirical Model for Describing the Small Field Penumbra in Radiation Therapy 