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Anatomical contouring variability in thoracic organs at risk
Ross McCall1, Grayden MacLennan1, Matthew Taylor1
1Medical Dosimetry Program, University of Wisconsin, La Crosse, WI.
Summary
Medical dosimetrists showed consistent thoracic organ contouring for lungs and spinal cord. However, accuracy for the heart and esophagus varied, with less experienced dosimetrists demonstrating inconsistent techniques.
Area of Science:
- Radiation Oncology
- Medical Physics
- Radiotherapy Planning
Background:
- Accurate delineation of organs at risk (OARs) is crucial for effective radiotherapy.
- Variability in OAR contouring can impact treatment efficacy and toxicity.
- Understanding factors influencing contouring consistency is essential for improving radiotherapy practices.
Purpose of the Study:
- To assess the consistency of thoracic organ at risk contouring among medical dosimetrists.
- To investigate the influence of education and experience on dosimetrist contouring accuracy.
- To identify potential areas for standardization in radiotherapy planning.
Main Methods:
- Three computed tomography (CT) datasets were used for contouring thoracic OARs (lungs, heart, spinal cord, esophagus).
- Thirteen medical dosimetrists from five institutions contoured OARs according to institutional standards.
- Dosimetrist contours were evaluated against physician-drawn gold standards using Dice coefficient and a penalty-based metric.
Main Results:
- No significant variation was found in the contouring consistency for the lungs and spinal cord.
- Intra-observer consistency for the esophagus and heart was observed in correctly contoured cases.
- Medical dosimetrists with lower metric scores exhibited inconsistent contouring methods for the heart and esophagus.
Conclusions:
- Thoracic OAR contouring consistency varies among medical dosimetrists, particularly for the heart and esophagus.
- Experience and adherence to established metrics may influence contouring accuracy.
- Further standardization of contouring guidelines and training could improve consistency in radiotherapy planning.
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