Cone beam CT dose reduction in prostate radiotherapy using Likert scale methods.
Br J Radiol
; 89(1059): 20150460, 2016.
Article
in En
| MEDLINE
| ID: mdl-26689092
ABSTRACT
OBJECTIVE:
To use a Likert scale method to optimize image quality (IQ) for cone beam CT (CBCT) soft-tissue matching for image-guided radiotherapy of the prostate.METHODS:
23 males with local/locally advanced prostate cancer had the CBCT IQ assessed using a 4-point Likert scale (4 = excellent, no artefacts; 3 = good, few artefacts; 2 = poor, just able to match; 1 = unsatisfactory, not able to match) at three levels of exposure. The lateral separations of the subjects were also measured. The Friedman test and Wilcoxon signed-rank tests were used to determine if the IQ was associated with the exposure level. We used the point-biserial correlation and a χ(2) test to investigate the relationship between the separation and IQ.RESULTS:
The Friedman test showed that the IQ was related to exposure (p = 2 × 10(-7)) and the Wilcoxon signed-rank test demonstrated that the IQ decreased as exposure decreased (all p-values <0.005). We did not find a correlation between the IQ and the separation (correlation coefficient 0.045), but for separations <35 cm, it was possible to use the lowest exposure parameters studied.CONCLUSION:
We can reduce exposure factors to 80% of those supplied with the system without hindering the matching process for all patients. For patients with lateral separations <35 cm, the exposure factors can be reduced further to 64% of the original values. ADVANCES IN KNOWLEDGE Likert scales are a useful tool for measuring IQ in the optimization of CBCT IQ for soft-tissue matching in radiotherapy image guidance applications.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Prostate
/
Prostatic Neoplasms
/
Radiotherapy Planning, Computer-Assisted
/
Cone-Beam Computed Tomography
Limits:
Humans
/
Male
Language:
En
Journal:
Br J Radiol
Year:
2016
Document type:
Article