English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Purpose  Maximum (MIP) and average intensity projection (AIP) CTs allow rapid definition of internal target volumes in a 4D-CT. The purpose of this study was to assess the accuracy of these techniques in a large patient cohort in combination with simulations on a lung phantom.    Methods  4DCT data from a self-developed 3D lung phantom and from 50 patients with lung tumors were analyzed. ITVs were contoured in maximum (ITV MIP ) and average intensity projection (ITV AIP ) and subsequently compared to ITVs contoured in 10 phases of a 4D-CT (ITV 10 ). In the phantom study additionally a theoretical target volume was calculated for each motion and compared to the contoured volumes.    Results  ITV 10  overestimated the actual target volume by 9.5% whereas ITV MIP  and ITV AIP  lead to an underestimation of − 1.8% and − 11.4% in the phantom study. The ITV MIP  (ITV AIP ) was in average − 10.0% (− 18.7%) smaller compared to the ITV 10 . In the patient CTs deviations between ITV 10  and MIP/AIP were significantly larger (MIP: – 20.2% AIP: -33.7%) compared to this. Tumors adjacent to the chestwall, the mediastinum or the diaphragm showed lower conformity between ITV 10  and ITV MIP  (ITV AIP ) compared to tumors solely surrounded by lung tissue. Large tumor diameters (> 3.5 cm) and large motion amplitudes (> 1 cm) were associated with lower conformity between intensity projection CTs and ITV 10− .    Conclusion  The application of MIP and AIP in the clinical practice should not be a standard procedure for every patient, since relevant underestimation of tumor volumes may occur. This is especially true if the tumor borders the mediastinum, the chest wall or the diaphragm and if tumors show a large motion amplitude.

Moving targets in 4D-CTs versus MIP and AIP: comparison of patients data to phantom data