Radiation dose reduction to the eye lens in head CT using tungsten functional paper and organ-based tube current modulation. Issue 124 (March 2020)

• Record Type: Journal Article
• Authors: Kosaka, Hiroyuki; Monzen, Hajime; Amano, Morikazu; Tamura, Mikoto; Hattori, Shota; Kono, Yuki; Nishimura, Yasumasa
• Is Part Of: European journal of radiology. Issue 124(2020)
• Publication Date: 2020-03
• Subjects: Tungsten functional paper -- Dose reduction -- Organ-based tube current modulation -- Computed tomography -- Eye lens; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2020.108814
• Languages: English
• ISSNs: 0720-048X

Abstract

Highlights: Eye lens are high radiosensitive organ. We explored dose reduction rate against eye lens with TFP shield and TCM. TFP shield plus TCM with 4 cm-gap can maintain image quality in head CT. TFP shield plus TCM gives adequate reduction ability. Abstract: Purpose: We investigated whether a tungsten functional paper (TFP) shield and/or organ-based tube current modulation (TCM) can reduce the dose to the eye lens. Materials and methods: All scans were performed using our routine head examination protocol (spiral acquisition, 120 kVp, noise Index 3.5) with an anthropomorphic head phantom. The dose reduction rate was measured by the following methods with a scintillation fiber optic dosimeter: (a) without any dose reduction techniques (Original scan), (b) TFP shield, (c) TCM, and (d) TFP shield plus TCM. Image noise and CT number were obtained and compared between the three groups. In addition, image noise in method (d) was measured with varying distances between the TFP shield and eye lens. Results: The reduction rates using TFP shield, TCM, and TFP shield plus TCM compared with those for the Original scan were 17.8 %, 13.6 %, and 27.7 %, respectively. Image noise (mean ± standard deviation) in the anterior region for the Original scan, TFP shield, TCM, and TFP shield plus TCM were 4.1 ± 0.2, 4.6 ± 0.2, 4.4 ± 0.3, and 5.0 ± 0.2, while the CT numbers were 19.3 ± 0.8, 23.8 ± 0.8, 19.6 ± 0.8, and 24.1 ± 0.8, respectively. Increasing the distance between the TFP and the eye significantly decreased the CT number when using TFP shield plus TCM ( p < .05). Conclusion: TFP shield plus TCM reduced the dose to the eye lens in head CT while maintaining image quality with an air gap between the TFP and skin surface.