Room: Exhibit Hall | Forum 9
Purpose: To explore a method of automatic organ dose calculation of CT patients by obtaining scanning parameters and patient figure of each CT DICOM image.
Methods: Through cross-system communication with hospital PACS, CT image DICOM files could be read and the scanning parameters (kVp, mAs, collimation width, etc.) of each case of CT examination were collected automatically in real time, and a cross-sectional image which is was collected in the middle, and the parameter related to patient figure known as water equivalent diameter(Dw), were calculated. Based on the reference patient model, organ doses were simulated slice by slice using Monte Carlo method. The patient specific organ doses were calculated by combining the CT scan parameters obtained from DICOM files slice by slice(tube voltage, mAs and collimation width), and the dose results were revised according to patient size(Dw) using correction factors.
Results: 339 cases of thoracic CT automatic tube current modulation scanning data were read through PACS system, and the absorbed dose of lung, breast and heart in each case was calculated respectively. The results showed that the doses of lung, breast and heart were 18.30Â±2.91mGy, 15.13 Â±2.75mGy and 17.87Â±2.96mGy respectively in small size patients(Dw<22cm), and 21.89Â±4.60mGy, 18.16 Â±4.13mGy and 21.46Â±4.60mGy respectively in medium-sized patients(Dw from 22cm to25cm), 24.98Â±4.40mGy, 20.81Â±3.66mGy and 24.77Â±4.46mGy respectively in large size patients(Dw larger than 25cm).
Conclusion: An automatic method of calculation of organ dose to patients undergoing tube current modulated CT exams with DICOM files is established.The attenuation of radiation to trunk tissue in PA direction may result in the lower breast dose. The dose of each organ showed an increasing trend with the increase of body size. The reason is that the increase of body size in ATCM mode leads to the increase of scanning conditions (mAs).
Funding Support, Disclosures, and Conflict of Interest: This work was supported by the Natural Science Foundation of China (grant number 11475047)
Not Applicable / None Entered.