Chiron P, Demoulin L, Wytrykowski K, Cavaignac E, Reina N, Murgier J. Radiation dose and magnification in pelvic X-ray: EOS™ imaging system versus plain radiographs.
Orthop Traumatol Surg Res 2017;
103:1155-1159. [PMID:
28942025 DOI:
10.1016/j.otsr.2017.07.018]
[Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/29/2017] [Accepted: 07/24/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND
In plain pelvic X-ray, magnification makes measurement unreliable. The EOS™ (EOS Imaging, Paris France) imaging system is reputed to reproduce patient anatomy exactly, with a lower radiation dose. This, however, has not been assessed according to patient weight, although both magnification and irradiation are known to vary with weight. We therefore conducted a prospective comparative study, to compare: (1) image magnification and (2) radiation dose between the EOS imaging system and plain X-ray.
HYPOTHESIS
The EOS imaging system reproduces patient anatomy exactly, regardless of weight, unlike plain X-ray.
MATERIAL AND METHOD
A single-center comparative study of plain pelvic X-ray and 2D EOS radiography was performed in 183 patients: 186 arthroplasties; 104 male, 81 female; mean age 61.3±13.7years (range, 24-87years). Magnification and radiation dose (dose-area product [DAP]) were compared between the two systems in 186 hips in patients with a mean body-mass index (BMI) of 27.1±5.3kg/m2 (range, 17.6-42.3kg/m2), including 7 with morbid obesity.
RESULTS
Mean magnification was zero using the EOS system, regardless of patient weight, compared to 1.15±0.05 (range, 1-1.32) on plain X-ray (P<10-5). In patients with BMI<25, mean magnification on plain X-ray was 1.15±0.05 (range, 1-1.25) and, in patients with morbid obesity, 1.22±0.06 (range, 1.18-1.32). The mean radiation dose was 8.19±2.63dGy/cm2 (range, 1.77-14.24) with the EOS system, versus 19.38±12.37dGy/cm2 (range, 4.77-81.75) with plain X-ray (P<10-4). For BMI >40, mean radiation dose was 9.36±2.57dGy/cm2 (range, 7.4-14.2) with the EOS system, versus 44.76±22.21 (range, 25.2-81.7) with plain X-ray. Radiation dose increased by 0.20dGy with each extra BMI point for the EOS system, versus 0.74dGy for plain X-ray.
CONCLUSION
Magnification did not vary with patient weight using the EOS system, unlike plain X-ray, and radiation dose was 2.5-fold lower.
LEVEL OF EVIDENCE
3, prospective case-control study.
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