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. 2011 Oct;36(4):192-7.
doi: 10.4103/0971-6203.89965.

A simple plan evaluation index based on the dose to critical structures in radiotherapy

Ramachandran Prabhakar  1 , Goura K Rath
Affiliations

A simple plan evaluation index based on the dose to critical structures in radiotherapy

Ramachandran Prabhakar et al. J Med Phys. 2011 Oct.

Abstract

The dose to critical structures plays a very important role in treatment plan evaluation and forms a major challenging parameter in radiotherapy treatment planning. In this study, a simple index, Plan Normal tissue complication Index (PNI) has been proposed for treatment plan evaluation based on the dose to surrounding critical structures. To demonstrate the proposed index, four different critical treatment sites that include the prostate, upper abdominal cancer, lung, and head and neck were selected for this study. A software progam (PNIcalc) has been developed to compute the PNI from the exported dose-volume histogram data and from the tissue tolerance data published by Emami et al. and Kehwar et al. The software also shows the parameters that exceed the threshold limits of dose-volume parameters presented in the QUANTEC recommendations (2010). In all the studied cases, PNI gave an overall picture of the dose received by the critical structures and also indicate the fractional volume exceeding the tolerance limit. The proposed index, PNI gives a quick comparison and selection of treatment plans that result in reduced dose to the critical structures. It can be used as an additional tool for routine treatment plan evaluation in external beam radiotherapy.

Keywords: Critical structures; plan evaluation; radiation oncology; tolerance dose; treatment planning system.

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Conflict of interest statement

Conflict of Interest: None declared.

Figures

Figure 1
Figure 1
Software module for comparing two rival plans based on PNI
Figure 2
Figure 2
Comparison of prescription isodose color wash for 3-F MLC plan (3D-CRT) and IMRT for UAC
Figure 3
Figure 3
Comparison of dose-volume histograms for 3-F MLC and IMRT treatment plans
Figure 4
Figure 4
Comparison of 3-F MLC plan and IMRT for lung cancer
See this image and copyright information in PMC

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