numbers are affected by the beam hardening and streaking artifacts that the shield
ultimately causes. Additionally, it notes
that using an automated exposure control (AEC), such as tube current modulation (TCM), without the use of bismuth
shielding is more effective in reducing
patient dose while not affecting the image
quality. 13 It should also be noted the study
described used foam padding between the
shield and the patient; the results found
that although the streaking was minimized, useful information was lost due
to attenuation of the beam. 13
The American Association of Physicists in Medicine (AAPM) recommends
the method of MDCT dose reduction to
be through the use of TCM, a form of
AEC, and has made the recommendation
that these other methods be used to reduce patient dose. 14 Although TCM is a
very effective method of dose reduction,
not all CT scanners have this option.
Until this is a mandatory option on all
scanners, the use of bismuth shielding
still appears relevant in protecting patients from increased dose to radiosensitive organs during CT imaging.
The principle all radiologic technologists
work toward is to acquire diagnostic examinations for the radiologist to interpret while using the ALARA principle.
From the literature, it appears that using
in-plane bismuth shielding during CT
examinations can substantially reduce
the patient’s radiosensitive organ tissue
dose absorbed. Also, it appears the use
of the bismuth shielding does not affect image quality. The opposition studies cannot be dismissed; however, until
standardized equipment is an option for
all departments with CT, recommendation would be to use in-plane bismuth
The literature could have been more
detailed when discussing the use of
in-plane shielding of the testes for CT
examinations. Even though only one
study was included that discussed the
use of this type of shielding for the testes,
the authors felt it was worth including
because of the results. Additionally, re-
search studies regarding the benefits of
female gonadal in-plane bismuth shield-
ing could be beneficial.
1Fricke BL, Donnelly LF, Frush DP, et al. In-plane bismuth breast shields for pediatric
CT: Effects on radiation dose and image
quality using experimental and clinical data.
AJR Am J Roentgenol. 2003;180:407–411.
2Saunders J, Ohlerth S. CT physics and
In: Schwarz T., Saunders S., eds. Veterinary
Computed Tomography. United States:
John Wiley & Sons Ltd; 2011.
3Thomtom FJ, Paulson EK, Yoshizumi TT,
Frush DP, Nelson RC. Single versus muti-detector row CT: Comparison of radiation
doses and dose profiles. Acad Radiology.
2003; 10( 4):379–385.
4Kalra MK, Dang P, Singh S, Saini S, Shepard,
JO. In-plane shielding for CT: Effect of off-centering, automatic exposure control, and
shield-to-surface distance. Korean J Radiol.
2009; 10( 2):156–163.
5Coursey C, Frush, DP, Yoshizumi T, Ton-cheva G, Nguyen G, & Greenberg SB
(2008). Pediatric chest MDCT using tube
current modulation: Effect on radiation
dose with breast shielding. Am J Roentgenol. 2008;190: W54–W61.
6Hopper AD, King SH, Lobell ME, TenHave
TR, Weaver JS. The breast: In-Plane x-ray
protection during diagnostic thoracic
CT—Shielding with bismuth radioprotec-tive garments. Radiol. 1997;205:853–858.
7Hopper KD, Neuman, JD, King SH, Kunselman
AR. Radioprotection to the eye during
CT scanning. Am J Neuroradiol. 2001;22:
8Leswick DA, Hunt MM, Webster ST, Flade-land DA. Thyroid shields versus z-axis
automatic tube current modulation for
dose reduction at neck CT. Radiol.
9McLaughlin DJ, Mooney RB. Dose reduction
to radiosensitive tissues in CT. Do commercially available shields meet the users’
needs? Clin Radiol. 2004;59:446–450.
10Mukundan S Jr, Wang PI, Frush DP, Yoshizumi T, Marcus J, Kloeblen E, Moore M.
MOSFET dosimetry for radiation dose
assessment of bismuth shielding of the
eye of children. Am J Roentgenol. 2007;
11Parker MS, Hui FK, Camacho MA, Chung JK,
Broga DW, Sethi NN. Female breast radiation exposure during CT pulmonary angi-ography. Am J Roentgenol. 2005;185:
12Yilmaz MH, Yasar D, Albayram S, et al.
Coronary calcium scoring with MDCT:
The radiation dose to the breast and the
effectiveness of bismuth breast shield.
Eur J Radiol. 2006;61( 1):139–143.
13Wang J, Xinhui D, Christner JA, et al. Bismuth shielding, organ-based tube current
modulation, and global reduction of tube
current for dose reduction to the eye at
head CT. Radiol. 2012;262:191–198.
14The American Association of Physicists in
Medicine. AAPM position statement on
the use of bismuth shielding for the purpose of dose reduction in CT scanning.
2012. Available at: http://www.aapm.org/
org/policies/. Accessed March 22, 2012.
Kyle Morford, ARRT, RT(R)(CT) is a CT/MRI technologist
in Indianapolis, IN. He will be graduating from
Midwestern State University with a bachelor of science
in radiologic sciences degree in May 2012. He can be
contacted at firstname.lastname@example.org.
Dr. Lynette Watts, PhD, R T(R) is an assistant professor
in the associate and baccalaureate radiologic
sciences programs at Midwestern State University
in Wichita Falls, TX. She can be contacted at