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Table 1 Dosimetric variations for the HRCTV, bladder, rectum, sigmoid and intestine between planning CT and pre-delivery CBCT

From: Intra-fractional dosimetric analysis of image-guided intracavitary brachytherapy of cervical cancer

 

CT

CBCT

Variation

Range of difference

P

HRCTV

Volume (cc)

54.1 ± 17.2

53.1 ± 16.9

 − 2.0 ± 3.3%

0.02–6.8

 < 0.001

D90 (cGy)

606.4 ± 39.3

599.1 ± 45.8

1.2 ± 4.5%

0.1–79.1

0.120

D90 (EQD2, cGy)

813.0 ± 72.6

800.1 ± 83.6

1.2 ± 6.1%

0.1–156.0

0.139

Bladder

     

Volume (cc)

81.4 ± 53.5

81.7 ± 48.0

7.9 ± 36.7%

0.3–146.1

0.957

D2cc (cGy)

391.6 ± 74.8

389.2 ± 71.9

 − 0.6 ± 17.1%

1.8–167.8

0.810

D2cc (EQD2, cGy)

552.5 ± 151.1

542.6 ± 151.2

2.7 ± 26.6%

4.2–355.2

0.772

Rectum

Volume (cc)

46.2 ± 13.9

41.9 ± 15.5

 − 6.9% ± 34.1%

0.02–22.5

0.001*

D2cc (cGy)

302.9 ± 84.4

327.0 ± 86.9

9.3 ± 14.6%

0.6–168.0

0.001*

D2cc (EQD2, cGy)

379.1 ± 157.1

425.7 ± 169.3

15.0 ± 24.0%

0.7–336.2

0.001*

Sigmoid

Volume (cc)

24.8 ± 15.72

24.28 ± 11.1

19.9 ± 68.2%

0.2–48.9

0.763

D2cc (cGy)

301.5 ± 85.8

312.5 ± 74.6

7.2 ± 20.5%

1.7–130.3

0.127

D2cc (EQD2, cGy)

376.9 ± 146.6

393.7 ± 130.4

11.4 ± 31.9%

2.8–210.4

0.192

Small intestine

Volume (cc)

401.0 ± 115.0

394.0 ± 145.7

 − 0.5 ± 26.7%

2.3–360.7

0.705

D2cc (cGy)

411.2 ± 60.3

418.2 ± 83.4

1.5 ± 12.6%

0.8–138.8

0.422

D2cc (EQD2, cGy)

591.9 ± 130.9

614.2 ± 190.0

3.4 ± 20.7%

2.0–353.6

0.293

  1. Relative differences between parameters (volume, D90 and D2cc) from two images sets were calculated as Difference = (Valuepre − Valueplan)/Valueplan. A positive value means that the volume/dose obtained for pre-delivery image was higher than that on the plan image
  2. *P < 0.05