Kelly McGrady of Krueger-Gilbert Health Physics on tomosynthesis, where it came from, and the current and future uses of the modality.

1. Tomosynthesis:
Origination and Applications
By
Kelly McGrady MS, RT(R)
Krueger-Gilbert Health Physics, Inc.

2. Overview
 What is Tomosynthesis?
 Origination
 Reasons for Development
 Applications
 Orthopedic Tomosynthesis
 Chest Tomosynthesis
 Breast Tomosynthesis
 FDA-approved

3. What is Tomosynthesis?
 Tomosynthesis is a method to reconstruct multiple
slices through a volume.
 Similar to CT
 Timeline
 1930s – Theorized
 1970s – Termed Tomosynthesis
 1980s – Forgotten about
 2000s – Resurgence
 Currently, mammography is the only modality with
an FDA-approved tomosynthesis unit.

4. Origination
 Conventional Linear
Tomography
 Conventional
tomography a
process that uses
geometric blurring
with a specified
plane of interest.
 Anything above or
below the plane of
interest is blurred.
www.mswestfalia.com/ares_rad.html

5. Conventional Linear Tomography
 Advantages
 Depth localization
 Disadvantages
 Image blur from out of
plane anatomy
 Only acquires one slice at a
time, and therefore it would
require an excessive dose
to acquire a volume.
 Shift to
www.e-
Computed Tomography radiography.net
http://www.radiology-equipment.com/ct-scanners.c

6. Computed Tomography (CT)
 Gold Standard
 Advantages
 Volumetric images
 Reduces
overlapping
structures
 Reconstruct many
different planes
 High sensitivity
 Disadvantages

7. Nov. 2, 2001 FDA Public Health Notification of the Radiation R
Jan. 24, 2010 Radiation Offers New Cures, and Ways to Do Har
Feb. 9, 2010 F.D.A. to Increase Oversight of Medical Radiation
Feb. 25, 2010 Radiation Bills Raise Question of Supervision
Feb. 26, 2010 At Hearing on Radiation, Calls for Better Oversig
April 9, 2010 F.D.A. Toughens Process for Radiation Equipmen
July 31, 2010 After Stroke Scans, Patients Face Serious Health

8. Percent Contribution from Various
Sources of Exposure
As of 2005, x-rays CT makes up for
were listed on the
24%
National Toxicology of all exposure
Program's "11th
Report on
Carcinogens."

9. How do you image with:
 Less blur than
conventional
tomography?
 Volumetrically with a
lower dose than CT?

10. Reasons for Development
 CT “has been classified in the highest
exposure class of all radiodiagnostic
techniques.” – Lancet 2004
 The development of tomosynthesis has
provided a possible way to reduce the exposure
while still being able to acquire volume of images.

11. Three Methods of Motion
 Full Isocentric
 Partial Isocentric
 Parallel Path Motion
 Most often used because it is the easiest to
reconstruct
 Magnification remains the same throughout

12. Tomosynthesis Applications
 Research in uses
for:
 Orthopedic
imaging
 Chest imaging
 Breast imaging
 Other
possibilities
 Dental Courtesy of Dr. Dobbins

13. Orthopedic Tomosynthesis
 Uses
 Arthritic Changes
 Implants
 Research
 Henry Ford Hospital
 Standing knees
 Hips
 Shoulder
 Harvard
 Measuring changes in bone structure (narrowing of joints)
 Australia
 VXA (Volumetric X-ray Absorptiometry)

14. Orthopedic Tomosynthesis
 Advantages
 Lower dose than CT
 Avoids streak artifacts from metal
 Less stringent positioning
 Disadvantages
 Not able to have flexible image reconstruction

15. http://www.shimadzu.com/products/medical/tomosynthesis.html

16. Chest Tomosynthesis
 Patient positioned in the PA or
lateral position
 Volumetric imaging with parallel
path tube motion. S
U
 Research with Nodule Localization Tube B
 Duke University J
E
 Studies have indicated up to 3x
C
more sensitive than a conventional T
Detector
CXR
 Currently only researching in the PA
position at this site.

17. Comparison with other Modalities
Conventional CXR CT
 Advantages  Advantages
 Reduced overlapping  Lower Dose
structures  Lower Cost
 Disadvantages  Better resolution in
 Reading Time the x & y direction
 Disadvantages
 Limited Depth
Resolution (z-
direction)
 Doesn’t have flexible
image reconstruction

18. Chest Tomosynthesis
 Case Studies
 Each study includes:
 Conventional Chest X-ray
 Dual Energy Chest X-ray
 Tomosynthesis Images (63 images)
 CT

19. CT Axial Image
R
L

20. Conventional Chest Radiograph

21. Dual Energy Chest Radiograph

22. Tomosynthesis Image

23. CT Axial Image

24. Conventional Chest Radiograph

25. Dual Energy Chest Radiograph

26. Tomosynthesis Image

27. Research Results of Nodule
Localization

28. Breast Tomosynthesis
 Purpose
 To address the
limitations of digital
mammography
 Dose
 Tomo dose ~ Dose of
a conventional
mammography
exposure
 Less for dense breasts
 Combination is less
http://www.hologic.com/en/breast-
than the ACR imaging/selenia-dimensions-

29. Breast Cancer Statistics
 1 in 8 will develop breast cancer in their lifetime
 12% incidence in the female population
 Leading cause of death for women 40 – 55 years
old
 Early detection is believed to save thousands of
lives
 Death rates due to breast cancer have decreased
dramatically since the 1990s due to:
 Awareness
 Early Detection
 Treatment Advances
 Most significant risks are
 Gender

30. Mammography
 Gold Standard  Movement to digital
 Potential to hide
pathology due to
superimposition.
www.hastingsimagingcenter.co

31. Breast Tomosynthesis
 Advantages
 Reduces
superimposition
 Reduced recall rate
 Improved cancer
detection rate
 Possibility to reduce
compression
 Disadvantages
 Microcalcifications
identification
http://www.hologic.com/en/breast-imaging/selenia-dimensions-tomosynthesis/clinical-b

32. Conclusions
 Tomosynthesis is an emerging
new modality.
 FDA-approved in Mammography
 Research is being done to add to
the diagnostic areas it can be
used.
 Alternative to CT

33. Thank You