Application of organ dose modulation technology in CT plain scanning of head / 中国介入影像与治疗学

ABSTRACT

Objective: To investigate the effectiveness of organ dose modulation (ODM) on dose reduction and image quality in CT plain scanning of head. Methods: A total of 100 patients who underwent head CT plain scanning were continuously collected. The patients were randomly divided into experimental group and control group with 50 cases in each group. ODM was applied in orbital region during CT plain scanning in experimental group, while CT plain scanning of head was performed in control group, and the parameters of scanning remained unchanged in both groups. Tube currents on different directions (anterior, posterior, left and right) of the orbital region were recorded, and volume CT dose index (CTDIvol) and dose length product (DLP) were recorded to calculate effective dosage (ED). ROI of the pons and bilateral cerebellar hemispheres were selected for measurement and calculation of objective noise and SNR. The imaging quality was subjectively graded as 1-5 points. Results: In experimental group, the tube current on anterior direction of head CT scanning area was significantly lower than that in control group (t=9.72, P=0.01). There was no statistical difference of CTDIvol, DLP, ED (all P>0.05), nor of objective noise in the pons and bilateral cerebellar hemispheres on posterior cranial fossa level and SNR between the two groups (all P>0.05). Subjective assessment showed all the image quality scores were ≥3 and could meet diagnostic needs in the two groups. No statistical difference of image quality score was found between the two groups (Z=0.25, P=0.31). Conclusion: During CT plain scanning of head, the application of ODM can reduce the tube current in the direct direction (anterior), thereby reduce the radiation dose in the orbital region and obtain image quality that can meet diagnostic requirements, meanwhile protect the sensitive organs.