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Table 4 Available reference data for PTV margin definition

From: The potential failure risk of the cone-beam computed tomography-based planning target volume margin definition for prostate image-guided radiotherapy based on a prospective single-institutional hybrid analysis

Author

Year

Pts

Image data sets

Contouring error (Intra-observer error)

  

Contouring error (Intra-observer error)

  

Matching error (Intra-observer error)

  

Matching error (Intra-observer error)

  

Intrafractional error

  

Observation method

∑

σ

Observation method

∑

σ

Observation method

∑

σ

Observation method

∑

σ

Observation method

∑

σ

Rasch (21)

1999

18

CT and MRI images

vrt

Intraobserver variability evaluated by 3 ROs CT volumes were larger than the axial MR volumes in 52 of 54 delineations.

            

lng

–

  

–

  

–

  

–

  

lat

            

Moseley (13)

2007

15

547 MV-and kV-CBCT data sets

vrt

    

ST in kV CBCT compared with FM in kV CBCT

1.97

2.15

5 Observer over 5 Pts. in ST matching with kV CBCT

1.61

2.86

   

lng

–

–

  

2.07

2.29

2.21

2.85

–

  

lat

    

0.57

0.85

0.61

1.5

   

Beltran (39)

2008

40

images from 1532 fractions

vrt

       

2 individuals over 40 frs. of 10pts. in FM matching with kV OBI

0.3

0.4

 

0.90

1.80

lng

–

–

  

–

  

0.5

0.3

FM in kV OBI

1.00

1.20

lat

       

0.3

0.2

 

0.60

1.30

Bylund (27)

2008

24

MV CBCT

vrt

    

20 MV CBCT images from 10 pts. evaluated by 3 experienced radiation oncologists 2 times per each pts. with 1-month interval variations were 1.6 mm, 1.6 mm, and 1.8 mm in the dimensions of AP, LR, and SI

   

lng

–

–

  

–

  

lat

       

Graf (10)

2009

23

images from 184 fractions

vrt

           

2.30

2.70

lng

–

–

  

–

  

–

  

FM in kV OBI

1.90

2.30

lat

           

1.10

1.40

Lutgendorf (34)

2011

8

CT, MR, and CBCT

vrt

Evalulated by ROs. For MR and CT images r (xCOM) and r (yCOM) did not exceeded 0.8 mm, whereas r (zCOM) was 0.8 mm and 1.3 mm, respectively

Evaluated by 7 ROs. The RMS of inter-observer standard deviations (r) for all patients was largest on CBCT for all three axes. RMS of the COM displacement on CBCT images was 0.4 mm, 1.1 mm, 1.7 mm in left-right, anterior-posterior and cranio-caudal directions, respectively.

   

lng

–

  

lat

   

Morrow (26)

2012

34

kV CBCT

vrt

             

lng

–

–

  

20 users

  

20 users

  

–

  

lat

             

Oehler (35)

2014

20

172 and 52 CBCTs before and after RT and 507 kV/kV images

vrt

 

3 experienced ROs contoured without MR images

1.52

 

ST in CBCT compared with FM in CBCT (NA due to with endrectal balloon)

0.77

1.09

   

FM in CBCT (NA due to with endrectal balloon)

1.39

1.62

lng

–

2.03

 

0.36

0.17

–

  

1.36

1.39

lat

 

1.68

 

0.49

0.93

   

0.92

0.97

Hirose This study

2018

25

Each 1177 kV OBI and kB CBCT image datasets before RT, and 1177 kV

vrt

           

0.85

1.47

lng

–

–

  

–

  

–

  

FM in kV OBI

1.00

1.66

lat

           

0.43

0.75

OBI and 206 kV CBCT image datasets after RT

vrt

    

ST in kV CBCT compared with FM in kV OBI

0.69

1.23

   

ST in CBCT (NA due to bias and less reliability)

0.68

1.08

lng

–

–

  

0.85

1.41

–

  

0.66

1.21

lat

    

0.39

0.76

   

0.25

0.50

  1. PTV planning target volume, RO radiation oncologist, CT computed tomography, MR magnetic resonance, ST soft tissue matching, FM fiducial marker matching, kV kilo voltage, MV mega voltage, CBCT cone-beam computed tomography, OBI on-board imaging, Pts patients, AP anterior to posterior, LR left to right, SI superior to inferior, COM center-of-mass, RMS root mean square, NA not applicable, vrt vertical, lng longitudinal, lat lateral
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Radiation Oncology

ISSN: 1748-717X

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