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MDCT Safety IssuesMDCT Safety Issues
Kimberly E. Applegate, MD, MS Kimberly E. Applegate, MD, MS
Riley Hospital for ChildrenRiley Hospital for Children
Indiana UniversityIndiana University
Financial disclosures: none
OverviewOverview FDA warning on devicesFDA warning on devices
Contrast injectorsContrast injectors
Creatinine in childrenCreatinine in children
(Sedation)(Sedation)
CT and medical radiationCT and medical radiation The “Image Gently Campaign”The “Image Gently Campaign”
CT is a popular toolCT is a popular tool
11stst clinical use: 1972 clinical use: 1972
Poorly monitored but rapid increase in usePoorly monitored but rapid increase in use
25% worldwide CT use is in USA25% worldwide CT use is in USA
Estimate*: 260,000,000/yr WorldEstimate*: 260,000,000/yr World
65,000,000/yr USA65,000,000/yr USA
Estimate: >7 million CTs in childrenEstimate: >7 million CTs in children
1 in every 4-10 Americans get CT annually1 in every 4-10 Americans get CT annually
*NRCP 2002*NRCP 2002
CT and MRI rated most important CT and MRI rated most important innovation in 20innovation in 20thth century century
healthcarehealthcare
Fuchs VR, Sox HC. Health Affairs 2001;20:30-42Fuchs VR, Sox HC. Health Affairs 2001;20:30-42Survey of leading general internists in practiceSurvey of leading general internists in practice274/387 responses, anonymous274/387 responses, anonymousRanked 30 innovationsRanked 30 innovations Based on “importance to your patient population”Based on “importance to your patient population”
CT and MRI ranked number 1!CT and MRI ranked number 1!
Things I used to know…Things I used to know…
Iodinated contrast is bad for kidneysGadolinium contrast is safe for patient with renal insufficiencyMRI is unsafe for patients with pacemakers and similar devicesUnder controlled condition, MRI may be safe including with deep brain stimulatorsCT is safe for patients with pacemakers and similar devicesRecent FDA advisory – Occasional discharge of devices, including vagal stimulators from multidetector CT
Pacemakers and MDCTPacemakers and MDCT
FDA warning July 14, 2008:
Unintended “shocks” (i.e., stimuli) from neurostimulators
Malfunctions of insulin infusion pumps
Transient changes in pacemaker output pulse rate
McCollough et al. Radiology 2007; 243McCollough et al. Radiology 2007; 243 Phantoms, defib and pacer devices Oversensing 20/21 at max dose (17/20 std dose)
RecommendationsRecommendations
Determine device type (after scout?) Determine device type (after scout?)
If practical, move external devices out of If practical, move external devices out of scan range scan range
Shut off neurostimulatorsShut off neurostimulators
Minimize x-ray exposure to device by: Minimize x-ray exposure to device by: Using the lowest possible x-ray tube current Using the lowest possible x-ray tube current
consistent with obtaining the required image consistent with obtaining the required image qualityquality
Minimize x-ray beam dwell time over the device Minimize x-ray beam dwell time over the device SCBTMR: Bismuth shield over device SCBTMR: Bismuth shield over device
Creatinine in ChildrenCreatinine in ChildrenSuggested cut-off levelsSuggested cut-off levels
Neonates* to 6 months: >0.3Neonates* to 6 months: >0.3
6 months-1 year: >0.66 months-1 year: >0.6
1-5 yrs: >0.81-5 yrs: >0.8
6-12 ys: >1.06-12 ys: >1.0
For children >12 years old: creat >1.1For children >12 years old: creat >1.1
For adults >21 years old: creat >1.5For adults >21 years old: creat >1.5
based on Schwartz formula (muscle mass)based on Schwartz formula (muscle mass)
IV flow rates 0.75-2 ml/secIV flow rates 0.75-2 ml/sec
Power-Injectable Venous Catheters:Power-Injectable Venous Catheters:Quality of enhancement &Quality of enhancement &
Quality of life issue for patientsQuality of life issue for patients
Children:Children:• PICCs (4,5 Fr)PICCs (4,5 Fr)• Central lines Central lines (8-10 Fr)(8-10 Fr)
Question 1Question 1
There is direct evidence that radiation There is direct evidence that radiation from medical imaging causes cancer.from medical imaging causes cancer.
A.A. TrueTrue
B.B. FalseFalse
Answer: False Answer: False
Indirect evidence from Hiroshima Indirect evidence from Hiroshima Atomic Bomb survivorsAtomic Bomb survivors
Linear No Threshold ModelLinear No Threshold Model
““It should be noted, however, that It should be noted, however, that the inability to detect increased the inability to detect increased [cancer] risks at very low doses [cancer] risks at very low doses
does not mean that those does not mean that those increases do not exist.”increases do not exist.”
UNSCEAR 2000UNSCEAR 2000
What is Low-level What is Low-level Radiation?Radiation?
< 100-150 mSv< 100-150 mSv
……or 3-10 abdominal CTsor 3-10 abdominal CTs
Pierce and Pierce and Preston (2000)Preston (2000)
50,000 survivors 50,000 survivors (1988-1994)(1988-1994)
Measurable risk Measurable risk of fatal cancer at of fatal cancer at low dose low dose 50-150 mSv50-150 mSv
Monument to martyrs of radiationMonument to martyrs of radiation
NAS—BEIR VIINAS—BEIR VII NCRPNCRP ICRPICRP NCINCI FDAFDA Radiology: RSNA, SPRRadiology: RSNA, SPR
Low-level Radiation Harmful? Low-level Radiation Harmful? Support:Support:
Question 2Question 2What is the relative risk of a What is the relative risk of a severesevere allergic allergic
reaction to iodinated contrast versus reaction to iodinated contrast versus fatal cancer induction from an abdominal fatal cancer induction from an abdominal CT in a child?CT in a child?
A.A. 100:1100:1B.B. 10:110:1C.C. 1:11:1D.D. 1:101:10E.E. 1:1001:100
Understanding RisksUnderstanding Risks
Risk of Risk of severe severe allergic reaction from allergic reaction from low osmolar IV contrast: low osmolar IV contrast: • lower in children than adultslower in children than adults• 1:100,0001:100,000
Risk of fatal cancer induction from 1 Risk of fatal cancer induction from 1 (adult dose) abdominal CT scan in a (adult dose) abdominal CT scan in a child:child:• 1:1,0001:1,000 (Brenner, AJR 2001) (Brenner, AJR 2001)
Question 3- RadiographyQuestion 3- Radiography
Is there an added risk of breast cancer after Is there an added risk of breast cancer after adolescent exposure to spine adolescent exposure to spine radiographs for scoliosis evaluation.radiographs for scoliosis evaluation.
A.A. YesYes
B.B. NoNo
Answer 3: YesAnswer 3: YesScoliosis Radiographs and Scoliosis Radiographs and Breast Cancer RiskBreast Cancer Risk
M Morin-Doody et al. Spine 2000M Morin-Doody et al. Spine 2000
NIH study of 138,000 radiographsNIH study of 138,000 radiographs
Dose dependent excess risk of later Dose dependent excess risk of later breast cancer*breast cancer*
**Most were AP rather than PAMost were AP rather than PA
Our very own Our very own CatScanCatScan
CT exams represent 2/3 medical radiation
exposure in USA
Bismuth ShieldsBismuth ShieldsChest CT & female breast doseChest CT & female breast dose
Breast, thyroid, & eye Breast, thyroid, & eye bismuth shields reduces bismuth shields reduces dose by 30% (dose by 30% (F&L Medical, F&L Medical, Vandegrift, PA)Vandegrift, PA)
Lead apron shielding Lead apron shielding outside of scan areas outside of scan areas (politically correct)(politically correct)
AJR 2005; Parker et al.AJR 2005; Parker et al. CTA for PE studies: 20 CTA for PE studies: 20
mSvmSv 2 view Mammogram: 2 2 view Mammogram: 2
mSvmSv
Technique--Bismuth ShieldsTechnique--Bismuth Shields
Coursey C et al. AJR 2008;190(1)Coursey C et al. AJR 2008;190(1)
Pediatric chest MDCT using tube current Pediatric chest MDCT using tube current modulation: effect on radiation dose with modulation: effect on radiation dose with breast shielding (GE)breast shielding (GE)
Place shield after obtaining scout image Place shield after obtaining scout image to avoid Auto mA compensation due to to avoid Auto mA compensation due to density of shielddensity of shield
ED 35% lower; breast dose 26% lowerED 35% lower; breast dose 26% lower
Question 4 - RadiosensitivityQuestion 4 - Radiosensitivity
Boys and girls are at equal risk of cancer Boys and girls are at equal risk of cancer induction from radiation.induction from radiation.
A.A. TrueTrue
B.B. FalseFalse
Differential radiation riskDifferential radiation risk NAS 1990: women NAS 1990: women 5%5% higher cancer higher cancer death risk than mendeath risk than men BEIR VII 2005: BEIR VII 2005: women women 38%38% higher cancer death risk than higher cancer death risk than
menmen Infants Infants 3-4x3-4x higher risk compared to adults higher risk compared to adults
aged 20-50aged 20-50 Girl infants Girl infants doubledouble risk of boy infants! risk of boy infants!
www.ieer.org/comments/beir/beir7pressrel.htmlwww.ieer.org/comments/beir/beir7pressrel.html
Lack of understanding of Lack of understanding of CT dosesCT doses
Lee et al 2004Lee et al 2004
Lee et al radiology 2004
Question 5 - CTQuestion 5 - CT
What is the estimated contribution of What is the estimated contribution of CT to future cancer risk in the CT to future cancer risk in the USA?USA?
A.A. .01%.01%
B.B. .1%.1%
C.C. 1%1%
D.D. 10%10%
Answer: 1-2% Answer: 1-2% Future Cancers from CTFuture Cancers from CT
Brenner D and Hall E. Computed Brenner D and Hall E. Computed tomography--an increasing source of tomography--an increasing source of radiation exposureradiation exposure NEJM 2007 29;357NEJM 2007 29;357
Estimate that up to 2% future cancers in Estimate that up to 2% future cancers in USA population due to current use of CTUSA population due to current use of CT
Marie Curie: Martyr to Radiation?Marie Curie: Martyr to Radiation?
First winner of 2 Nobel First winner of 2 Nobel prizes: prizes: -Physics (1903,w/ husband) Physics (1903,w/ husband) -Chemistry (1911)Chemistry (1911)-Only mother-daughter Nobel Only mother-daughter Nobel laureate pair (daughter Irene laureate pair (daughter Irene continued her research)continued her research)--Discovered Radium, --Discovered Radium, PoloniumPolonium--Died of leukemia, age 67, --Died of leukemia, age 67, presumed from radiation presumed from radiation exposureexposure
Radiation Safety
American College of Radiology white American College of Radiology white paper on radiation dose in medicine. paper on radiation dose in medicine. AmisAmis ES ES JrJr, , Butler PFButler PF, , Applegate Applegate KEKE,etal; JACR 2007,etal; JACR 2007
Collaboration and Steps for all stakeholdersCollaboration and Steps for all stakeholders Consumers, vendors, physicists, techs…Consumers, vendors, physicists, techs…
Dose reference levels in new guidelines and all Dose reference levels in new guidelines and all Appropriateness CriteriaAppropriateness Criteria
Special Focus on Children Special Focus on Children
RadiosensitivityRadiosensitivity
Longer Life ExpectancyLonger Life Expectancy
CT scans in CT scans in childrenchildren often performed using often performed using
“adult”“adult” techniques techniques resulting in higher resulting in higher radiation doseradiation dose
The “Image Gently” CampaignThe “Image Gently” Campaign
Launched Jan. 2008 by SPR in Launched Jan. 2008 by SPR in alliance with:alliance with: Radiologists, Physicists, Radiologists, Physicists,
Technologists, PediatriciansTechnologists, Pediatricians
Education focuse to decrease Education focuse to decrease radiation exposure in childrenradiation exposure in children CT first moduleCT first module
Www.ImageGently.orgWww.ImageGently.org
Image GentlyImage Gently Campaign Campaign
Marilyn J. Goske, MD, Alliance Chair and Marilyn J. Goske, MD, Alliance Chair and Chair, SPR Board of Directors – Cincinnati Chair, SPR Board of Directors – Cincinnati Children’s HospitalChildren’s Hospital Goals/ Background of Campaign Goals/ Background of Campaign Scientific Background and RationaleScientific Background and RationaleEducation/Marketing campaign overview Education/Marketing campaign overview and rolloutand rollout
The WebsiteThe Website
Alliance MembersAlliance Members
4 Founding: 4 Founding: SPR*,AAPM,ACR,ASRTSPR*,AAPM,ACR,ASRT
Now 33 organizationsNow 33 organizations
International (CAR, ESPR, RANZCR, SLARP)International (CAR, ESPR, RANZCR, SLARP)
Represent >500,000 membersRepresent >500,000 members
Five InitiativesFive Initiatives CT, NM, IR, CR/DR, FluoroCT, NM, IR, CR/DR, Fluoro
Three ComponentsThree Components Radiologists, Physicists, TechnologistsRadiologists, Physicists, Technologists Referring Physicians – ALARA, Referring Physicians – ALARA,
presentationspresentations ParentsParents
The MessageThe Message
Campaign ImpactCampaign Impact
>1500 imaging providers took pledge>1500 imaging providers took pledge
Website Website > 72,000 visits> 72,000 visits > 6,000 downloads of guidelines on pediatric > 6,000 downloads of guidelines on pediatric
CT protocolsCT protocols
ConclusionConclusion““Medical technology (including Medical technology (including
radiology) itself is not the problem. It is radiology) itself is not the problem. It is why, how and how often it is used and why, how and how often it is used and by whom which creates the problem.” by whom which creates the problem.”
Chisholm R. Guidelines for radiological investigations Chisholm R. Guidelines for radiological investigations [editorial]. BMJ 1991;303:797-780[editorial]. BMJ 1991;303:797-780
CTA of Aortic StentsCTA of Aortic Stents
Lack of Understanding of Dose: Lack of Understanding of Dose: 2004 UK survey2004 UK survey
Contrast ReactionsContrast Reactions
Who is at increased risk?
Prior reactions, allergies– not shellfish
Prophylaxis regimens: Methylprednisolone (Medrol) 32mg p.o. 12
and 2 hours prior to contrast administration
Procedures for HydrationProcedures for Hydration
Saline 10 ml/kg IV bolus over 30-60 minutes Saline 10 ml/kg IV bolus over 30-60 minutes prior to CT (or 500ml)prior to CT (or 500ml)
No benefit: ½ NS, lasix, dopamine, mannitol, No benefit: ½ NS, lasix, dopamine, mannitol, aminophylline, ?fenoldopan, aminophylline, ?fenoldopan,
?N-acetylcysteine; ?N-acetylcysteine;
Clear benefit of low vs hi osmolar, non-ionic Clear benefit of low vs hi osmolar, non-ionic vs ionic contrast agents; ? isosmolar benefit vs ionic contrast agents; ? isosmolar benefit if renal dz (visipaque)if renal dz (visipaque)
Bicarb may helpBicarb may help
Why are Pediatric Radiation Doses so High?
• Unfamiliarity = high detail - pediatric disorders - normal variations - growth - complicated equipment
• Few guidelines, no regulation• Most pediatric imaging is done - not in academic centers - not by subspecialists
Lack of understanding of DoseLack of understanding of DoseAbdominal CT vs CXRAbdominal CT vs CXR
An abdominal CT deposits the equivalent An abdominal CT deposits the equivalent dose of about how many chest dose of about how many chest radiographs?radiographs?
A.A. 1010
B.B. 5050
C.C. 100100
D.D. 500500
Steering CommitteeSteering CommitteeMarilyn Goske, MD, Alliance Chair - Marilyn Goske, MD, Alliance Chair - SPR SPR
Kimberly Applegate, MD, Kimberly Applegate, MD, SPR and ACR SPR and ACR
Jennifer Boylan Jennifer Boylan SPR SPR
Penny ButlerPenny ButlerACR and AAPM ACR and AAPM
Michael Callahan, MD, Michael Callahan, MD, SPR SPR
Brian Coley, MD, Brian Coley, MD, SPR and ACRSPR and ACR
Shawn FarleyShawn FarleyACR ACR
Donald Frush, MD Donald Frush, MD ACR and SPRACR and SPR
.. Marta Hernanz-Schulman, MD, FACRMarta Hernanz-Schulman, MD, FACRSPR and ACR SPR and ACR
Diego Jaramillo, MD, MPH, Diego Jaramillo, MD, MPH, SPR SPR
Neil Johnson, MDNeil Johnson, MDSPR SPR
Sue Kaste. DOSue Kaste. DOSPR SPR
Greg Morrison Greg Morrison ASRT ASRT
Keith Strauss, MDKeith Strauss, MDAAPM and SPRAAPM and SPR
Nora Tuggle Nora Tuggle ASRTASRT
Growth rate for Imaging Services (1997-2003)
High-tech 12.9%
Low-tech 4.5%
Distribution of Imaging Services (2003)
Low-tech80%
High-tech20%
15.8%
20%
MRI
CA
GR
(%
)
15%
10%
5%
0%
13.9%
11.4%
9.2% 8.3%7.2%
2.5%
NUCMED
CT INT MAM US X-RAY
Growth in high-tech services have made diagnostic imaging the fastest growing physician service in the Growth in high-tech services have made diagnostic imaging the fastest growing physician service in the United StatesUnited States
Projected Growth in Imaging Procedures (2000-2008)Projected Growth in Imaging Procedures (2000-2008)
Source: Sg2
281 299323
349374
401430
450471
Vo
lum
e o
f Im
agin
g
Pro
ced
ure
s (M
)
600
2000
500
400
300
200
100
02001 2002 2003 2004 2005 2006 2007 2008
Projected Growth 2002-2008Projected Growth 2002-2008MRIMRI CT ScanCT Scan UltrasoundUltrasound X-RAYX-RAY
133%133% 122%122% 57%57% (9%)(9%)
Imaging service volume will continue to increase as use of high-tech procedures drive growthImaging service volume will continue to increase as use of high-tech procedures drive growth
