Congress:
EuroSafe Imaging 2019
Keywords:
Action 4 - Dose management systems, Radioprotection / Radiation dose, CT, Dosimetry, Quality assurance
Authors:
M. Longo, V. Cannatà, P. Toma, A. Magistrelli, C. Polito, T. Insero, S. Donatiello, E. Genovese, B. Cassano
DOI:
10.26044/esi2019/ESI-0093
Conclusion and recommendations
In the present study,
a method for assessing DLPOV in helical scans has been theoretically described and experimentally validated.
It has been demonstrated that overscan is responsible from approximately 38% to 5% of the displayed DLP values for minimum and maximum planned scan lengths investigated in this study.
One advantage of the proposed methodology is its complete independence from console readings.
However,
the proposed methodology proposes a calculation based on set parameters and on measurement of scan time derived from waveform acquisitions instead of relying upon the scan time and length calculated by the console.
The only requirements to apply the proposed method are: (i) a phantom support have to be engaged,
(ii) a probe able to measure the dose-rate versus time profile with adequate sampling frequency to improve the accuracy of dose estimates.
The utility of this methodology is twofold: on one hand,
it can be used for quality assurance in helical scans and,
on the other hand,
ensures a feasible method to directly measure the overscan contribution with currently used CT dosimetric indices.
The proposed method for quantifying the DLPOV can be used to evaluate the clinical implication of overscanning and to optimize scanning protocols in order to reduce the impact of this extra-dose especially on critical organs.
It should be desirable that overscan dose should be evaluated for optimizing helical CT scan protocols with regard to the most efficient scanning in light of overscanning.