open access

Vol 20, No 5 (2015)
Original reearch articles
Published online: 2015-09-01
Submitted: 2014-02-18
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Influence of the type of imaging on the delineation process during the treatment planning

Weronika Jackowiak, Bartosz Bąk, Anna Kowalik, Adam Ryczkowski, Małgorzata Skórska, Małgorzata Paszek-Widzińska
DOI: 10.1016/j.rpor.2015.05.004
·
Rep Pract Oncol Radiother 2015;20(5):351-357.

open access

Vol 20, No 5 (2015)
Original reearch articles
Published online: 2015-09-01
Submitted: 2014-02-18

Abstract

Aim

The aim of this study was to compare the intra- and interobserver contouring variability for structures with density of organ at risk in two types of tomography: kilovoltage computed tomography (KVCT) versus megavoltage computed tomography (MVCT). The intra- and interobserver differences were examined on both types of tomography for structures which simulate human tissue or organs.

Materials and methods

Six structures with density of the liver, bone, trachea, lung, soft tissue and muscle were created and used. For the measurements, the special water phantom with all structures was designed. To evaluate interobserver variability, five observers delineated the structures in both types of computed tomography (CT).

Results

Intraobserver variability was in the range of 1–14% and was the largest for the liver. The observers segmented larger volumes on MVCT compared with KVCT for the trachea (79.56[[ce:hsp sp="0.25"/]]ccm vs.74.91[[ce:hsp sp="0.25"/]]ccm), lung (87.61 vs. 82.50), soft tissue (154.24 vs. 145.47) and muscle (164.01 vs. 157.89). For the liver (98.13 vs. 99.38) and bone (51.86 vs. 67.97), the volume on MVCT was smaller than KVCT. The statistically significant differences between observers were observed for structures with density of the liver, bone and soft tissue on KVCT and for the liver, lung and soft tissue on MVCT. For the structures with density of the trachea and muscles, there were no significant differences for both types of tomography.

Conclusions

During the contouring process the interobserver and intraobserver contouring uncertainty was larger on MVCT, especially for structures with HU near 80, compared with KVCT.

Abstract

Aim

The aim of this study was to compare the intra- and interobserver contouring variability for structures with density of organ at risk in two types of tomography: kilovoltage computed tomography (KVCT) versus megavoltage computed tomography (MVCT). The intra- and interobserver differences were examined on both types of tomography for structures which simulate human tissue or organs.

Materials and methods

Six structures with density of the liver, bone, trachea, lung, soft tissue and muscle were created and used. For the measurements, the special water phantom with all structures was designed. To evaluate interobserver variability, five observers delineated the structures in both types of computed tomography (CT).

Results

Intraobserver variability was in the range of 1–14% and was the largest for the liver. The observers segmented larger volumes on MVCT compared with KVCT for the trachea (79.56[[ce:hsp sp="0.25"/]]ccm vs.74.91[[ce:hsp sp="0.25"/]]ccm), lung (87.61 vs. 82.50), soft tissue (154.24 vs. 145.47) and muscle (164.01 vs. 157.89). For the liver (98.13 vs. 99.38) and bone (51.86 vs. 67.97), the volume on MVCT was smaller than KVCT. The statistically significant differences between observers were observed for structures with density of the liver, bone and soft tissue on KVCT and for the liver, lung and soft tissue on MVCT. For the structures with density of the trachea and muscles, there were no significant differences for both types of tomography.

Conclusions

During the contouring process the interobserver and intraobserver contouring uncertainty was larger on MVCT, especially for structures with HU near 80, compared with KVCT.

Get Citation

Keywords

Interobserver variability; Kilovoltage computed tomography; Megavoltage computed tomography; Delineation

About this article
Title

Influence of the type of imaging on the delineation process during the treatment planning

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 20, No 5 (2015)

Pages

351-357

Published online

2015-09-01

DOI

10.1016/j.rpor.2015.05.004

Bibliographic record

Rep Pract Oncol Radiother 2015;20(5):351-357.

Keywords

Interobserver variability
Kilovoltage computed tomography
Megavoltage computed tomography
Delineation

Authors

Weronika Jackowiak
Bartosz Bąk
Anna Kowalik
Adam Ryczkowski
Małgorzata Skórska
Małgorzata Paszek-Widzińska

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