Effect of Body Habitus on Radiation Dose During CT Fluoroscopy-Guided Spine Injections

Overview

Journal Interv Neuroradiol

Publisher Sage Publications

Specialty Neurology

Date 2014 Nov 4

PMID 25363254

Authors

Ronald J Viola

Giao B Nguyen

Terry T Yoshizumi

Sandra S Stinnett

Jenny K Hoang

Peter G Kranz

Affiliations

Soon will be listed here.

Abstract

This study investigated the degree to which body habitus influences radiation dose during CT fluoroscopy (CTF)-guided lumbar epidural steroid injections (ESI). An anthropomorphic phantom containing metal oxide semiconductor field effect transistor (MOSFET) detectors was scanned at two transverse levels to simulate upper and lower lumbar CTF-guided ESI. Circumferential layers of adipose-equivalent material were sequentially added to model patients of three sizes: small (cross-sectional dimensions 25×30 cm), average (34×39 cm), and oversize (43×48 cm). Point dose rates to skin and internal organs within the CTF beam were measured. Scattered point dose rates 5 cm from the radiation beam were also measured. Direct point dose rates to the internal organs ranged from 0.05-0.11 mGy/10mAs in the oversized phantom, and from 0.18-0.43 mGy/10mAs in the small phantom. Skin direct point dose rates ranged from 0.69-0.71 mGy/10mAs in the oversized phantom and 0.88-0.94 mGy/10mAs in the small phantom. This represents a 180-310% increase in organ point dose rates and 24-36% increase in skin point dose rates in the small habitus compared with the oversize habitus. Scatter point dose rates increased by 83-117% for the small compared to the oversize phantom. Decreasing body habitus results in substantial increases in direct organ and skin point doses as well as scattered dose during simulated CTF-guided procedures. Failure to account for individual variations in body habitus will result in inaccurate dose estimation and inappropriate choice of tube current in CTF-guided procedures.

References

Schauberger J, Kranz P, Choudhury K, Eastwood J, Gray L, Hoang J . CT-guided lumbar nerve root injections: are we using the correct radiation dose settings?. AJNR Am J Neuroradiol. 2012; 33(10):1855-9. PMC: 7964617. DOI: 10.3174/ajnr.A3096. View

Ware D, Huda W, Mergo P, Litwiller A . Radiation effective doses to patients undergoing abdominal CT examinations. Radiology. 1999; 210(3):645-50. DOI: 10.1148/radiology.210.3.r99mr05645. View

Singh S, Kalra M, Moore M, Shailam R, Liu B, Toth T . Dose reduction and compliance with pediatric CT protocols adapted to patient size, clinical indication, and number of prior studies. Radiology. 2009; 252(1):200-8. DOI: 10.1148/radiol.2521081554. View

Teeuwisse W, Geleijns J, Broerse J, Obermann W, van Persijn van Meerten E . Patient and staff dose during CT guided biopsy, drainage and coagulation. Br J Radiol. 2001; 74(884):720-6. DOI: 10.1259/bjr.74.884.740720. View

Gianfelice D, Lepanto L, Perreault P, Chartrand-Lefebvre C, Milette P . Value of CT fluoroscopy for percutaneous biopsy procedures. J Vasc Interv Radiol. 2000; 11(7):879-84. DOI: 10.1016/s1051-0443(07)61805-3. View

Joemai R, Zweers D, Obermann W, Geleijns J . Assessment of patient and occupational dose in established and new applications of MDCT fluoroscopy. AJR Am J Roentgenol. 2009; 192(4):881-6. DOI: 10.2214/AJR.08.1765. View

Bauhs J, Vrieze T, Primak A, Bruesewitz M, McCollough C . CT dosimetry: comparison of measurement techniques and devices. Radiographics. 2008; 28(1):245-53. DOI: 10.1148/rg.281075024. View

Carlson S, BENDER C, Classic K, Zink F, Quam J, Ward E . Benefits and safety of CT fluoroscopy in interventional radiologic procedures. Radiology. 2001; 219(2):515-20. DOI: 10.1148/radiology.219.2.r01ma41515. View

Leng S, Christner J, Carlson S, Jacobsen M, Vrieze T, Atwell T . Radiation dose levels for interventional CT procedures. AJR Am J Roentgenol. 2011; 197(1):W97-103. DOI: 10.2214/AJR.10.5057. View

10.

Schindera S, Nelson R, Toth T, Nguyen G, Toncheva G, DeLong D . Effect of patient size on radiation dose for abdominal MDCT with automatic tube current modulation: phantom study. AJR Am J Roentgenol. 2008; 190(2):W100-5. DOI: 10.2214/AJR.07.2891. View

11.

McCollough C, Leng S, Yu L, Cody D, Boone J, McNitt-Gray M . CT dose index and patient dose: they are not the same thing. Radiology. 2011; 259(2):311-6. PMC: 3079120. DOI: 10.1148/radiol.11101800. View

12.

Yanch J, Behrman R, Hendricks M, McCall J . Increased radiation dose to overweight and obese patients from radiographic examinations. Radiology. 2009; 252(1):128-39. DOI: 10.1148/radiol.2521080141. View

13.

Koenig T, Wolff D, Mettler F, Wagner L . Skin injuries from fluoroscopically guided procedures: part 1, characteristics of radiation injury. AJR Am J Roentgenol. 2001; 177(1):3-11. DOI: 10.2214/ajr.177.1.1770003. View

14.

Kim G, Hur J, Lee S, Lee H, Hong Y, Nam J . CT fluoroscopy-guided lung biopsy versus conventional CT-guided lung biopsy: a prospective controlled study to assess radiation doses and diagnostic performance. Eur Radiol. 2010; 21(2):232-9. DOI: 10.1007/s00330-010-1936-y. View

15.

Turner A, Zhang D, Khatonabadi M, Zankl M, DeMarco J, Cagnon C . The feasibility of patient size-corrected, scanner-independent organ dose estimates for abdominal CT exams. Med Phys. 2011; 38(2):820-9. PMC: 3037972. DOI: 10.1118/1.3533897. View

16.

Tsalafoutas I, Tsapaki V, Triantopoulou C, Gorantonaki A, Papailiou J . CT-guided interventional procedures without CT fluoroscopy assistance: patient effective dose and absorbed dose considerations. AJR Am J Roentgenol. 2007; 188(6):1479-84. DOI: 10.2214/AJR.06.0705. View

17.

Koenig T, Mettler F, Wagner L . Skin injuries from fluoroscopically guided procedures: part 2, review of 73 cases and recommendations for minimizing dose delivered to patient. AJR Am J Roentgenol. 2001; 177(1):13-20. DOI: 10.2214/ajr.177.1.1770013. View

18.

Wagner A . Selective lumbar nerve root blocks with CT fluoroscopic guidance: technique, results, procedure time, and radiation dose. AJNR Am J Neuroradiol. 2004; 25(9):1592-4. PMC: 7976407. View

19.

Huda W, Atherton J, Ware D, Cumming W . An approach for the estimation of effective radiation dose at CT in pediatric patients. Radiology. 1997; 203(2):417-22. DOI: 10.1148/radiology.203.2.9114097. View

20.

Brink J, Morin R . Size-specific dose estimation for CT: how should it be used and what does it mean?. Radiology. 2012; 265(3):666-8. DOI: 10.1148/radiol.12121919. View