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. 2016 May 9;50(3):254-62.
doi: 10.1515/raon-2016-0023. eCollection 2016 Sep 1.

Uncertainties in target volume delineation in radiotherapy - are they relevant and what can we do about them?

Barbara Segedin  1 , Primoz Petric  2
Affiliations

Uncertainties in target volume delineation in radiotherapy - are they relevant and what can we do about them?

Barbara Segedin et al. Radiol Oncol. .

Abstract

Background: Modern radiotherapy techniques enable delivery of high doses to the target volume without escalating dose to organs at risk, offering the possibility of better local control while preserving good quality of life. Uncertainties in target volume delineation have been demonstrated for most tumour sites, and various studies indicate that inconsistencies in target volume delineation may be larger than errors in all other steps of the treatment planning and delivery process. The aim of this paper is to summarize the degree of delineation uncertainties for different tumour sites reported in the literature and review the effect of strategies to minimize them.

Conclusions: Our review confirmed that interobserver variability in target volume contouring represents the largest uncertainty in the process for most tumour sites, potentially resulting in a systematic error in dose delivery, which could influence local control in individual patients. For most tumour sites the optimal combination of imaging modalities for target delineation still needs to be determined. Strict use of delineation guidelines and protocols is advisable both in every day clinical practice and in clinical studies to diminish interobserver variability. Continuing medical education of radiation oncologists cannot be overemphasized, intensive formal training on interpretation of sectional imaging should be included in the program for radiation oncology residents.

Keywords: delineation uncertainties; imaging; interobserver variability; target volume; training.

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Figures

Figure 1
Figure 1
MR images showing interobserver variability between an unexperienced RO and the reference contour in IGABT of 4 cervix cancer patients (from a workshop for RO residents at the Institute of Oncology Ljubljana).
Figure 2
Figure 2
Interobserver variability in delineation of the prostate. MR and CT images in different planes of the same patient are shown. Ability to discriminate prostate apex, base and lateral borders is superior on MRI. cor = coronal; sag = sagittal; tra = transverse40
See this image and copyright information in PMC

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