Korean J Radiol.  2009 Feb;10(1):51-57. 10.3348/kjr.2009.10.1.51.

Slot-Scan Digital Radiography of the Lower Extremities: a Comparison to Computed Radiography with Respect to Image Quality and Radiation Dose

• Lee KH
• Kwon JW
• Yoon YC
• Choi SH
• Jung JY
• Kim JH
• Lee SJ

• KMID: 1088678
• DOI: http://doi.org/10.3348/kjr.2009.10.1.51

Abstract

OBJECTIVE
To compare the slot-scan digital radiography (SSDR) of the lower extremity region and the computed radiography (CR) method with respect to the image quality and radiation exposure. MATERIALS AND METHODS: We enrolled 54 patients who underwent both the SSDR and CR of the lower extremities. The study evaluated and statistically compared the image quality of four features (outer cortex, inner cortex, trabeculae and intermuscular fat) at six different levels (pelvis, hip, femur, knee, tibia and ankle) between each method. The image quality was evaluated using a visibility scale, and the entrance skin dose was measured using a dosimeter at three different levels of a phantom (hip, knee, and ankle). RESULTS: The mean image visibility scale values for the SSDR method were significantly higher than for the CR method. The entrance skin dose for the SSDR method was 278 micro Gy at each level, compared to the entrance skin doses of the CR method, which were 3,410 micro Gy for the hip, 1,152 micro Gy for the knee, and 580 microGy for the ankle. CONCLUSION: Both the image quality and patient entrance skin dose data suggest that the SSDR method is superior to the CR method for the lower extremity musculoskeletal examination.

Keyword

Computed radiography; Slot-scan digital radiography; Lower extremities; Phantom

MeSH Terms

Adolescent
Adult
Aged
Aged, 80 and over
Female
Humans
Lower Extremity/*radiography
Male
Middle Aged
Radiation Dosage
*Radiographic Image Enhancement/methods
*Tomography, X-Ray Computed/methods
Young Adult

Figure

• 

  Fig. 1 16-year-old girl with cerebral palsy and right spastic hemiplegia. Standing anteroposterior radiography of lower extremities for computed radiography method (A) and scanogram of lower extremities (C) show relatively good image quality, however provide less overall resolution and contrast level when compared to slot-scan digital radiography method (D). In particular, intermuscular fat plane and detailed structure of joints are not well demonstrated in A. Small artifact (white arrowheads in A and B) is shown around right knee in A as well as magnification of right lower extremity at level of knee (B). Intermuscular fat plane around right proximal tibia (white arrows in D and E) trabeculae of both femoral necks, and differentiation of corticomedullary junction of lower extremities are seen more clearly in D, and in magnification view of right lower extremity at level of knee (E). Evaluated scores are as follows: pelvis - 5/6; hip - 5/6; femur - 6/8; knee - 5/7; tibia - 5/8; ankle - 4/6 with standing anteroposterior radiography of lower extremities of both computed radiography and slot-scan digital radiography methods, respectively.

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