Table 2 Mean gross tumor volume (GTV) and active tumor region (GTV_T) for three observers delineating target volumes using PET or MRI. Dice coefficients for inter observer PET, inter observer MRI, and intra observer comparing PET with MRI

1

118

143

0.88

0.84

0.84

62

84

0.83

0.83

0.76

2

173

150

0.86

0.77

0.83

70

102

0.86

0.79

0.68

3

70

65

0.84

0.79

0.85

47

50

0.81

0.64

0.72

4

36

23

0.80

0.67

0.70

5

7

0.60

0.55

0.52

5

13

17

0.85

0.60

0.74

4

10

0.64

0.72

0.49

6

11

18

0.73

0.72

0.49

3

9

0.47

0.59

0.20

7

21

19

0.59

0.70

0.70

4

7

0.36

0.69

0.53

8

27

40

0.85

0.81

0.71

3

15

0.73

0.65

0.42

9

36

36

0.84

0.84

0.69

15

16

0.72

0.80

0.60

10

26

39

0.79

0.73

0.69

6

20

0.73

0.65

0.42

11

9

16

0.64

0.69

0.58

4

6

0.56

0.54

0.40

12

14

16

0.71

0.79

0.69

3

9

0.62

0.75

0.43

13

64

85

0.90

0.76

0.77

27

51

0.82

0.81

0.66

14

26

20

0.78

0.76

0.72

7

11

0.46

0.69

0.52

15

23

30

0.70

0.63

0.67

6

7

0.72

0.73

0.53

16

8

10

0.58

0.69

0.68

1

1

0.53

0.67

0.44

17

32

32

0.82

0.75

0.80

6

10

0.63

0.61

0.51

18

49

48

0.84

0.77

0.84

19

21

0.76

0.78

0.78

19

108

118

0.51

0.60

0.82

46

73

0.77

0.72

0.73