A heart atlas for breast radiation therapy and the influence of delination education on both intra and interobserver variability

• Published in: Japanese journal of radiology Vol. 37; no. 5; pp. 420 - 430
• Main Authors: Kırlı, Meltem, Akçay, Doğukan, Barış, Mustafa Mahmut, Görken, İlknur Bilkay
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01-05-2019; Springer Nature B.V
• Subjects: Arteries; Atrium; Breast cancer; Consistency; Coronary artery; Dosage; Education; Heart; Imaging; Medicine; Medicine & Public Health; Nuclear Medicine; Observers; Original Article; Radiation; Radiation therapy; Radiology; Radiotherapy; Similarity; Statistical analysis; Ventricle; Breast radiotherapy; Cardiac subunit delineation; Heart atlas
• ISSN: 1867-1071; 1867-108X
• DOI: 10.1007/s11604-019-00819-1

Purpose
We developed a heart atlas for breast radiation therapy and evaluated the influence of education on intra and inter-observer similarity, and cardiac dose reporting.
Materials and methods
The data of 16 left breast cancer patients were analyzed. Eight observers delineated heart and cardiac subunits [left (LCA) and right (RCA) coronary arteries, left anterior descending artery (LAD), bilateral atrium and ventricles] before the education. A radiologist and radiation oncologist developed the atlas and delineated the gold standard (GS) volumes. Observers repeated the delineation after education. RT plans were made for pre/post-atlas contours. The similarity was assessed by Dice (DSC) and Jaccard (JSC) similarity coefficient indices. The absolute difference rate was calculated for the dose analysis.
Results
The inter-observer similarity increased in heart and all subunits. The intra-observer similarity showed a heterogeneous distribution. The absolute difference rate in dose reporting was statistically significant for the bilateral atrium, right ventricle, LAD, LCA + LAD, RCA’s maximum doses (
p
 < 0.05). The maximum dose reporting differences from the GS decreased from 16.9 to 8.9% for LAD (
p
 = 0.011); from 14.8 to 9.3% for LCA + LAD (
p
 = 0.010).
Conclusion
The cardiac atlas reduces the intra-interobserver differences and improves dose reporting consistency. The first intra-observer similarity analysis was made in our study and revealed the need for repeated education to increase the consistency.