J Korean Soc Radiol.  2017 Aug;77(2):89-96. 10.3348/jksr.2017.77.2.89.

Effective Dose in Abdominal Digital Radiography: Patient Factors

• Jang JS
• Koo HJ
• Yang HJ
• Park JH
• Cho YC
• Do KH

• KMID: 2386744
• DOI: http://doi.org/10.3348/jksr.2017.77.2.89

Abstract

PURPOSE
To identify independent patient factors associated with an increased radiation dose, and to evaluate the effect of patient position on the effective dose in abdominal digital radiography.
MATERIALS AND METHODS
We retrospectively evaluated the effective dose for abdominal digital radiography in 222 patients. The patients were divided into two groups based on the cut-off dose value of 0.311 mSv (the upper third quartile of dose distribution): group A (n = 166) and group B (n = 56). Through logistic regression, independent factors associated with a larger effective dose were identified. The effect of patient position on the effective dose was evaluated using a paired t-test.
RESULTS
High body mass index (BMI) (≥ 23 kg/m²), presence of ascites, and spinal metallic instrumentation were significantly associated with a larger effective dose. Multivariate logistic regression analysis revealed that high BMI [odds ratio (OR), 25.201; p < 0.001] and ascites (OR, 25.132; p < 0.001) were significantly associated with a larger effective dose. The effective dose was significantly lesser (22.6%) in the supine position than in the standing position (p < 0.001).
CONCLUSION
High BMI and ascites were independent factors associated with a larger effective dose in abdominal digital radiography. Significant dose reduction in patients with these factors may be achieved by placing the patient in the supine position during abdominal digital radiography.

MeSH Terms

Ascites
Body Mass Index
Humans
Logistic Models
Posture
Radiation Dosage
Radiographic Image Enhancement*
Radiography, Abdominal
Retrospective Studies
Supine Position

Figure

• 

  Fig. 1 Scatterplot and quadratic curve fitting showing the distribution of the effective dose for both the supine and standing positions according to the patient's body mass index (BMI). The effective dose is significantly decreased in the supine position than in the standing position, especially in patients with BMI > 23 kg/m2 (red dotted line).

• 

  Fig. 2 Box-plot showing the distribution of the effective doses according to patient position in groups A and B. *Outliers indicate values more than 1.5 times of upper quartile.

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