Measurement of lung tumor volumes using three-dimensional computer planning software
Autor: | Gillian M. Duchesne, Patrick Bowden, Andrew Wirth, Judy Andrews, Allan F. McKenzie, Michael P. Mac Manus, Michael J. Millward, David Ball, Richard Fisher |
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Rok vydání: | 2002 |
Předmět: |
Observer Variation
Analysis of Variance Cancer Research Contouring Lung Neoplasms Radiation business.industry medicine.medical_treatment Planning target volume Atelectasis medicine.disease Radiation therapy Imaging Three-Dimensional Oncology Carcinoma Non-Small-Cell Lung medicine Humans Radiology Nuclear Medicine and imaging Lung tumor In patient Tomography X-Ray Computed Nuclear medicine business Lung cancer Radiation treatment planning |
Zdroj: | International Journal of Radiation Oncology*Biology*Physics. 53:566-573 |
ISSN: | 0360-3016 |
Popis: | Purpose: To examine the interclinician variation in the definition of gross tumor volume (GTV) in patients undergoing radiotherapy for non-small-cell lung cancer (NSCLC), develop methods to minimize this variation, and test these methods. Methods and Materials: The radiotherapy planning computed tomography (CT) scans of 6 consecutive patients with NSCLC in which the radiologist was able to define and outline the GTV were used. Six oncologists independently contoured the tumors with the radiologist's markings as a guide using a three-dimensional treatment planning system. Separate contours were prepared using only mediastinal window settings and using both mediastinal and lung window settings. The volumes were calculated using the planning system software (series 1). Factors that resulted in interclinician variation were determined, and, after a 3-year interval, 5 of the 6 clinicians redefined the GTVs using a revised protocol aimed at minimizing variation (series 2). Results: For series 1, the interclinician variation in the measurement of volumes ranged from 5%, in the most tightly measured tumor, to 42%, in the most variable, but was, on average, 20%. Statistically significant differences were noted among the clinicians ( p = 0.002), that is, some clinicians tended to record relatively small and some relatively large volumes. The reasons for the variation among the oncologists included a tendency to include regions with a low probability of containing tumor, as if the oncologist were contouring a target volume; inclusion of adjacent atelectasis (ignoring the radiologist's outline); and variable treatment of spicules. When the exercise was repeated using the revised protocol (series 2), the degree of interclinician variation was reduced, with a range of 7–22% (average 13%). In series 2, the differences among the clinicians were not statistically significant ( p = 0.25). Conclusion: Despite major radiologic input, significant variation occurred in the delineation of the three-dimensional GTVs of NSCLC among oncologists. Standardization of the approach with guidelines resulted in a reduction in this variation. |
Databáze: | OpenAIRE |
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