Basics of Planning and Management of Patients during Radiation Therapy by Ashutosh Mukherji

Author:Ashutosh Mukherji
Language: eng
Format: epub, pdf
Publisher: Springer Singapore, Singapore

The inverse planning process can now identify many more dose distribution patterns that could achieve required distribution than was possible by manual optimization process.

14.7 Plan Evaluation from DVH

The shape and area under the DVH curve are used to ensure that the target volume is adequately covered with a homogeneous dose and that dose to critical structures is within acceptable limits. From this, the percentage of the volume of an organ receiving a given dose (d) can be read as V d (volume of tissue receiving dose “d”) or as D v (dose received by volume “v” of tissue). From the x-axis, the mean, median doses, etc. can be calculated. If DVHs are obtained from a series of patients in whom acute or late effects are recorded, points on the DVH can be correlated with the probability of these effects occurring.

Figure 14.21 shows a typical cumulative DVH. In this DVH, the main questions asked would be whether PTV coverage is adequate and whether the OARs are being adequately spared. Basically the area under a curve is the volume of tissue getting a dose, and the smaller this area, the better for an OAR . Also the tail of the curve should not ideally taper too much to the right as this will mean a smaller volume getting a higher dose. This is true even for the target volumes, i.e. the more the dose line tails towards right bottom (x-axis), the more is the maximum point dose to the target volume. This can be clinically significant if this maximal dose to OAR is in a serial organ like the spinal cord where even a small volume getting a very high dose can have catastrophic results.

Fig. 14.21 DVH of a typical case of brachytherapy

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.