Effects of Kilovoltage on Image Quality and Entrance Surface Dose in Lumbar Spine Digital Radiography

Document Type : Original Paper

Authors

Department of Diagnostic Imaging and Radiotherapy, Kulliyyah of Allied Health Sciences, International Islamic University of Malaysia, Jalan Sultan Ahmad Shah, Bandar Indera Mahkota, 25200 Kuantan Pahang

Abstract

Introduction: Digital radiography possesses a wide dynamic range and has a major advantage in producing an acceptable image of diagnostic value even though overexposure occurs. Lumbar spine (LS) radiography is the most common examinations that gives high radiation dose to patients and accounts for the highest collective population dose of any conventional radiographic examinations. As such, this study was carried out to ascertain the impact of image quality and entrance surface dose (ESD) with different exposure settings in the anteroposterior (AP) and lateral LS.
Material and Methods: The torso of the PBU-50 phantom was exposed to medium and high kilovoltage peak (kVp). A total of 14 images for LS were obtained. Relative image quality was assessed using Leeds Test Objects TOR CDR whilst the ESD was ascertained using an optically stimulated luminescence dosimeter.
Results: The results of Friedman test indicated a significant difference in image quality when using medium and high kVp. Wilcoxon signed-rank test also reflected a significant difference in ESD between the use of medium and high kVp for both AP and lateral LS.
Conclusion: Significant differences in image quality and ESD were obtained using medium and high kVp with medium kVp resulting in high contrast but low contrast sensitivity and vice versa. The findings of the present study indicated that the recommended kVp for AP LS was from 75kVp to 81kVp whilst for lateral LS the recommended kVp was from 85kVp to 90kVp for an average adult patient.

Keywords

Main Subjects


  1.  

    1. Hart D, Wall BF. UK population dose from medical x-ray examinations. European Journal Radiology. 2004; 50: 285-91.
    2. Moey SF, Shazli ZA, Sayed I. Dose Evaluation for Common Digital Radiographic Examinations in Selected Hospitals in Pahang Malaysia. Iran J Med Phys. 2017; 14: 155-61.
    3.       Clancy CL, O’Reilly G, Brennan PC, McEntee MF. The effect of patient shield position on gonad dose during lumbar spine radiography. Radiography. 2010; 16(2):131–5.
    4. Moey SF, Shazli ZA. Optimization of Dose and Image Quality in Full-field Digital and Computed Radiography Systems for Common Digital Radiographic Examinations. Iran J Med Phys. 2018; 15: 28-38.
    5. Seeram E. Optimization of the exposure indicator of a computed radiography imaging system as a radiation dose management strategy. Ph.D. thesis. Department of Medical Radiation Science, Faculty of Science, Charles Sturt University, Australia. 2012.
    6. Mattoon JS, Smith C. CE Breakthroughs in radiography: computed radiography. Direct. 2004; 4 (Jan): 58–66.
    7. Gibson DJ, Davidson RA. Exposure creep in computed radiography. A longitudinal study. Academic Radiology. 2012; 19(4): 458–62.
    8. Ludwig K, Ahlers K, Wormanns D, Freund M, Bernhardt TM, Diederich S, et al. Lumbar spine radiography: digital flat-panel detector versus screen-film and storage-phosphor systems in monkeys as a pediatric model. Radiology. 2003; 222: 453-9.
    9. Herrmann TL, Fauber TL, Gill J, Hoffman C, Orth DK, Peterson PA, et al. Best practices in digital radiography. Radiologic Technology. 2012; 84(1): 83–9.
    10. Sprawls P. The Physical Principles of Medical Imaging. 2nd ed. Madison: Sprawls; 1996.
    11. Carlton RR, Adler AM. Radiographic Imaging: Concept and Principles. 5th ed. New York: Delmar; 2013.
    12. Martin CJ. Optimization in general radiography. Biomed Imaging Interv J. 2007; 3(2): e18.
    13. Herrmann TL, Fauber TL, Gill J, Hoffman C, Orth DK, Peterson PA, et al. Best practices in digital radiography. Radiol Technol. 2012Íž 84:83–9.