Unified dosimetry index (UDI): a figure of merit for ranking treatment plans

Abstract

We have formulated a unified dosimetry index (UDI) that computes, for any given treatment plan, its deviations in terms of dose coverage, conformity, homogeneity, and dose gradient vis‐à‐vis an ideal plan (which we define as a dosimetry plan of perfect dose coverage, conformity, homogeneity, and step‐wise fall‐off to zero dose outside the planning target volume). In order to validate the UDI scoring system, 21 stereotactic cranial radiosurgery cases were evaluated retrospectively. The cases were planned on the BrainSCAN treatment planning system (BrainLAB, Feldkirchen, Germany) using 6 to 8 non‐coplanar static beams collimated with the micro multi‐leaf collimator (mMLC). We suggest a technique for creating a ranking system that can be utilized for plan evaluation and comparison between multiple plans. Under this system treatment plans are classified as “excellent”, “good”, “average”, or “poor”. The proposed ranking system can be utilized as a general guide for generating an optimal dosimetry plan for external beam radiation therapy.

Comparison of treatment plans: a retrospective study by the method of radiobiological evaluation

“…The dosevolume-based indices sum up complex dose distributions to a single index, which can be used to choose the optimal plan. Another study performed by Akpati et al [28] formulated a Unified Dosimetry Index (UDI) that reckons the deviations between treatment plans. This method uses an equation which is developed by combining different dosimetric objectives such as dose coverage, conformity, homogeneity and dose gradient.…”

A comparative study of RapidArc and intensity-modulated radiotherapy plan quality for cervical cancer treatment

“…By comparing the dosimetric components, it is observed that HI score good plans in opposite sense as CI and GI. [16] UDI scoring is essential method for determining which plan is better in cases where multiple dosimetry plans are generated. Good dosimetry plan is indicated by low UDI score.…”

“…Akapati et al [16] proposed UDI integrating contribution from all four above-mentioned dosimetric components. It is considered as an efficient tool to define ideal plan.…”

“…Therefore, the fourth objective can be indirectly achieved by quantifying the dose gradient. [16] Integral dose (ID) is the measure of total dose deposited in the whole body and This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms.…”

Evaluation of Gantry Angle Optimization for Imrt Treatment Planning Systems Using the Pareto Front Appro1ach

“…In another more clinical oriented study a comparison between conformal radiotherapy and IMRT was accomplished, again by scoring the data from the DVHs with the addition of using a biological model [14]. Other studies have made even more exhaustive attempts to evaluate treatment plans as for example Akpati et al [29] that introduced a unified dosimetry index in trying to rank the treatment plans.…”