방사선의학 웹진

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Abstract

PURPOSE:

To determine inter-observer variability in target volume definition of cervical cancer in radical and adjuvant radiotherapy (RT) settings.

METHODS:

Eight physicians contoured CTVs of 2 patients underwent definitive and postoperative RT. Each volume was analyzed using the individual/median volume ratio and generalized conformity index (CIgen). And center of mass (COM) of each contour was calculated. Expert agreement was quantified using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE).

RESULTS:

For definitive RT, the individual/median volume ratio ranged from 0.51 to 1.41, and CIgen was 0.531. Mean 3-dimensional distances of average to each COM were 7.8 mm. For postoperative RT setting, corresponding values were 0.65-1.38, 0.563, and 5.3 mm. Kappa value of expert agreement was 0.65 and 0.67, respectively. STAPLE estimates of the sensitivity, specificity, and kappa measures of inter-physician agreement were 0.73, 0.98, and 0.65 for the definitive and 0.75, 0.98, and 0.67 for the adjuvant radiotherapy setting. The largest difference was observed in the superior-inferior direction, particularly in the upper vagina and the common iliac area.

CONCLUSION:

As there was still some variability in target delineation, more detailed guidelines for target volume delineation and continuing education would help to reduce this uncertainty.

Author information

Joo JH1, Kim YS1, Cho BC1, Jeong CY1, Park W2, Kim HJ3, Yoon WS4, Yoon MS5, Kim JY6, Choi JH7, Choi Y8, Kim JY9.

1 Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, Republic of Korea.

2 Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.

3 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.

4 Department of Radiation Oncology, Korea University Ansan Hospital, Ansan, Gyeonggi-do, Republic of Korea.

5 Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Hwasun, Jeollanam-do, Republic of Korea.

6 Department of Radiation Oncology, the Catholic University of Korea, College of Medicine, Seoul, Republic of Korea.

7 Department of Radiation Oncology, Chung-Ang University Hospital, Seoul, Republic of Korea.

8 Department of Radiation Oncology, Dong-A University Hospital, Busan, Republic of Korea.

9 Center for Uterine Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi-do, Republic of Korea.