The document discusses the risks of brain tumor induction from head CT scans in children and adolescents. It notes that children are more susceptible than adults to radiation-induced cancer. Several large epidemiological studies have found an increased incidence of brain tumors and other neoplasms in pediatric patients who received head CTs, with one excess tumor estimated for every 3,000-10,000 CT exams in children under 10. The risk is very small but exists, so careful consideration of optimal scan frequency is warranted when head CTs are not definitively medically necessary. Lower dose 80 kV brain CT protocols have been shown to provide similar image quality to standard 120 kV scans with a 6.5% reduction in radiation dose.

2. Background
• CT; first clinical use in 1971 to image a
suspected frontal lobe tumor
• 82 M Ct scans @ 2016 in US
• 25-30 M head CTs
• Neoplastic induction from head CT
• Non-Contrast head CT deliver 2 mSv
• Background 3-6 mSv

3. Background
• Low susceptibility of brain tissue to
cytotoxic damage from radiation
• Children are more susceptible to
radiation-induced cancer
• LAR(Lifetime attributable risk) is ten fold
higher for an infant that for a middle-
aged adult patient

4. Background
• Repeat CT for Traumatic brain injury or
cerebrospinal fluid shunts can magnify
the potential risk

5. Purpose
• incidence and risk of brain tumor
induction associated with head CT to
children and adolescents

6. Information sources & search
protocol

7. Study selection
• The Preferred Reporting Items for
Systematic Reviews and Meta-Analysis
(PRISMA) guideline[21.22]

8. Data Extraction
• Population prevalence of head CT
procedures, per-scan
• cumulative radiation dose level
• Predicted or actual tumor incidence
• Brain absorbed dose, biological effective
dose
• Lifetime attributable absolute risk,
• Absolute risk, excess relative risk, hazard
ratio,

9. Burden of pediatric head CT
• 720 head CT per 100,000 children

10. Predicted Tumor risk
• Brain dose; 55 mGy
• Effective dose; 1.6 mSv
• LAR; 0.056% [23,25,27,29,30]

11. Measured tumor risk
• 5 studies[14,31-34], re-analysis[35]
• 995,091 patients, brain dose 41±9 mGy

13. Measured tumor risk
• ERR of 1.29 (or ERR of 2.25%/mGy)
• ERR of 140% or a 2.4 fold increase in
brain tumor risk from single head CT

14. Discussion
• CT cancer risk has focused on pediatrics
– Children are more sensitive than adult
– Have longer life expectancy
• Data from higher dose exposure(atomic
bomb) there is no basis for any assertion
of cancer risk from low-dose radiation

15. Discussion
• Since 2012, Five large epidemiological
studies[14,31-34], increased incidence of
neoplasm (predominantly brain tumors)
in pediatric patients from head CTs
• One excess neoplasm may be expected
per 3,000 – 10,000 CT exams in children
under age 10

16. Discussion
• From UK study, re-compute cancer risk,
the corrected risk were reduced ~ 30%
• single head CT exams gives HR=2.32,
HRs for brain tumors increased to 4.58
after two head CTs, 10.4 after three or
more scans.
• HR for malignant brain cancer was 12.3
after two head CTs

17. Conclusions
• A newly epidemiological evidence has
corroborated non-zero estimates for CT
associated brain tumor risk in pediatric
populations
• Risk of tumor induction from pediatric
head CT is very small, on the order of
one excess tumor per 3,000 – 10,000
scans

18. Conclusions
• Minimal estimated risk of tumor induction
from pediatric head CT is heavily offsets by
the benefits of diagnostic imaging
• Understanding and quantifying neoplasm
risk of hed CT has motivated significant
dose reduction efforts for pediatric CT
protocols
• Head CT is often indisputable (trauma or
suspected stroke), careful consideration is
warranted as to the optimal frequency of
scans

19. 진단참고수준

20. CT 장치의 정도관리
한국의료영상품질관리원

21. Noize 측정

22. 임상영상검사
• 일반정보20점, 영상정보80점
• 각각 60점/100점 이상 합격

31. Conclusion
• 80 kV brain CT
– were shown to be with improved gray
matter-white matter contrast-to–noise ratios.
– Similar overall image quality
• 6.5% radiation dose reduction
• 80 kV brain CT can be an acceptable
technique to replace a standard 120 kV
CT scan in children

32. 우리 병원은?