Optimized Camera-based Patient Positioning in CT: Impact on Radiation Exposure.
Conditions: Radiation Dosage
Sponsor: Dr. Panagiota Manava

Optimized Camera-based Patient Positioning in CT: Impact on Radiation Exposure.  
 
 
ClinicalTrials.gov ID: NCT05135208 
29-August-2022 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Study Protocol and Statistical Analysis Plan 
 
Title: Optimized Camera-based Patient Positioning in CT: Impact on Radiation Exposure. 
Description of the study: 
To investigate different options for patient positioning. Target parameters are the achievable 
differences in radiation exposure and the deviation from isocenter.  
Design: 
Retrospective 
Status: The patients are positioned laser guided on the CT table by the trained technicians for the CT 
examinations. 
A 128-slice single-source CT scanner was used. This CT scanner system with an integrated 3D camera 
system offers a recommendation for the patient's table positioning. 
Statistical analysis  
For radiation exposure analysis: 
Power analysis was performed with a sample size of 1806 patients for each group to detect an 
effective size of 0.12 for radiation exposure analysis based on test measurements on an 
anthropomorphic phantom.  
Isocenter accuracy: 
According to previous results, a power analysis for the isocenter accuracy was performed with a 
group size of 10 patients in each group.  
A chi-squared test was used to analyze patients’ characteristics.   
Levine’s test was used for calculating the equality of variances followed by student’s t-test for 
independent samples.  A p value < 0.05 was considered indicating statistically significant differences. 
For the study, the patients are not additionally exposed to radiation or contrast media. Tests that 
require a higher radiation exposure (perfusion) are excluded. 
The evaluation of the data is carried out anonymously via a dose management system. 
The duration of the study will be approximately 12 months. 
 
 
 
 
 
 
 
 
 
 
 

 
Results:  
 
Cameramode 
H 
Mean value 
Standard- deviation 
P value 
isocenter 
off 
1557 
-10.9 
16.6 
0.000 
on 
1561 
-3.8 
10.1 
Reconstruction diameter 
off 
1557 
400.8 
40.8 
0.251 
on 
1561 
399.2 
40.1 
pitch 
off 
1557 
0.8 
0.2 
0.894 
on 
1561 
0.8 
0.2 
mAS max 
off 
1557 
219.8 
114.2 
0.042 
on 
1561 
211.2 
112.2 
kVp 
off 
1557 
94.8 
18.6 
0.796 
on 
1561 
95.0 
18.8 
Table height 
off 
1557 
170.0 
20.4 
0.000 
on 
1561 
165.6 
16.2 
age 
off 
1557 
64.1 
15.8 
0.423 
on 
1561 
63.7 
16.1 
BMI 
off 
1557 
26.1 
5.4 
0.957 
on 
1561 
26.1 
5.5 
weight 
off 
1557 
76.2 
18.4 
0.885 
on 
1561 
76.3 
18.0 
height 
off 
1557 
1704.6 
97.8 
0.506 
on 
1561 
1707.0 
96.4 
 
Legend: 
mAs = milliampere-seconds; kVp = kilovoltage peak; BMI= Body Mass Index 
 
 
 
 
 
 
 
 
 
 

 
Cameramode 
H 
Mean value 
Standard- 
deviation 
P value 
ED 
off 
1557 
3.5 
2.9 
0.053 
on 
1561 
3.3 
2.7 
DLP 
off 
1557 
342.0 
280.7 
0.033 
on 
1561 
321.1 
266.7 
CTDIvol 
off 
1557 
6.8 
4.6 
0.011 
on 
1561 
6.4 
4.3 
Organ dose of 
eye lens 
off 
1557 
0.1 
0.1 
0.21 
on 
1561 
0.1 
0.3 
Organ dose of 
heart 
off 
1557 
3.9 
3.1 
0.443 
on 
1561 
3.8 
3.0 
Organ dose of 
colon 
off 
1557 
3.5 
3.9 
0.015 
on 
1561 
3.1 
3.6 
Organ dose of 
ovaries 
off 
1557 
3.1 
3.6 
0.902 
on 
1561 
3.1 
3.5 
Organ dose of 
red bone 
marrow 
off 
1557 
2.4 
2.1 
0.049 
on 
1561 
2.3 
1.9 
Organ dose of 
thyroid gland 
off 
1557 
0.3 
0.4 
0.205 
on 
1561 
0.3 
0.8 
Organ dose of 
upper colon 
off 
1557 
3.7 
3.9 
0.012 
on 
1561 
3.3 
3.6 
Organ dose of 
salivary glands 
off 
1557 
0.0 
0.0 
0.226 
on 
1561 
0.0 
0.2 
Organ dose of 
esophagus 
off 
1557 
2.3 
1.7 
0.355 
on 
1561 
2.2 
1.7 
 
Legends: Dose Length Product (DLP) in mGy*cm, Effective Dose (ED) in mSv, CT Dose Index 
(CTDIvol) in mGy, and Organ Dose in mSv.