Biomarker OPERRA Workshop 2015, Gomolka
Increased radiation sensitivity in newborns
and children under 5 years of age compared to adults
after in vitro CT exposure
Biomarker OPERRA Workshop 2015, Gomolka
Background
High number of CT-examinations (11,3 Mill/Jahr 2011)
– ca. 1% in children in Germany
Relatively high organ doses compared to conventional Xray diagnostic (in few cases 500times increased)
60% Head CT: doses between 2-15 mGy
40% of children CT in the age group from 0-5 Jahren
Presumably most sensitive age window
Biomarker OPERRA Workshop 2015, Gomolka
• The U.S. Environmental Protection Agency (EPA) recommends (U.S. EPA, 2003a) 10-times risk adjustment for the first 2 years of age, 3-times adjustment in the age groupe from 3-15 years (Chemical noxes and radiation)
• Epidemiological studies (BEIRVII): 2-10times increased tumor risk after age of exposure < 5
• Contradictory results for low doses:
Recently 3 CT studies confirmed a small but definite cancer risk induced by CT scans early in life (UK, Australia, Taiwan)
Age dependent radiation sensitivity – Epidemiological evidence
Biomarker OPERRA Workshop 2015, Gomolka
Experimental in vivo studies
• In vivo studies: internal exposure after Chernobyl fall out
• Chromosome aberrations after in vivo CT examinations
Problem: dosimetry to the blood
Biomarker OPERRA Workshop 2015, Gomolka
What are the reasons for an increased sensitivity in children?
• Scanners are not well adapted to the body proportions
• Tissues with higher cell division rate
• Increased numbers of stem cells in tissues
• Longer life time expectancy
Unclear: Intrinsic cellular radionsensitivity?
Biomarker OPERRA Workshop 2015, Gomolka
In vitro pilot-CT Studie: Radiosensitivity in different
age groups
(Ethik-Kommission der Bayerischen Ärztekammer) according to § 18 of the Professional Code of Conduct for Doctors in Bavaria (Berufsordnung für die Ärzte Bayerns)
In vitro CT-study on repair of radiation-induced DNA-damage as a function of age and sex. Ethik-Kommsion Nr. 11083
Biomarker OPERRA Workshop 2015, Gomolka
Study Design
Umbilical cord blood
Children (0-5 years)
Adults (> 20 years)
In vitro CT irradiation
GammaH2AX Dicentrics
Biomarker OPERRA Workshop 2015, Gomolka
Adults
N=17
Umbilical Cord
N=15
Children
N=15
Ethnicity Caucasians Caucasians Caucasians, 1 African
Response Rate 100% 20%-90% (depending on the
hospital)
80%
Smoking Non-smokers: 14
Smokers: 3
Non-smoking parents: 13
Smoking parents: 1
Not reported: 1
Non-smoking parents: 5
Smoking parents: 9
Not reported: 1
Regular
medication
Histaminblocker (1),
Thyronajod (1),
Domperidon (1), ASS Atid
(1), Pantoprazol (1),
Simvabeta
- No
Diseases Allergy: 6
Hyperthyreosis: 1
- Circumcission (11)
Inguinal hernia (2)
Hydrocele (2)
Dicentric Assay N=12 N=11 N=10
GammaH2AX N=12 N=11 N=13
Both Assays N=12 N=11 N=8
Characterization of the study groups
Biomarker OPERRA Workshop 2015, Gomolka
Irradiation Conditions
Spiral-CT-Scanner Toshiba Aquilion/LB Modell TSX-201A/1K
0 mGy (sham exposure), 41 mGy (± 0.5 mGy) and 978 mGy dose (± 16 mGy)
• Controlled by LiF Thermoluminecence
• Voltage: 120 kVp, • Current: 400 mA (high dose) and 50
mA (low dose) • Dynamic Scan within 15 sec. or 3 x
15sec
• Homogeneous dose distribution
Biomarker OPERRA Workshop 2015, Gomolka
Characteristics of the applied biomarker
Highly radiation specific (Dicentrics)
Highly sensitive for low dose exposure (GammaH2AX)
Low intra individual variation (Dicentrics, GammaH2AX?)
Low inter indivdual variation (Dicentrics, GammaH2AX?)
In vivo exposure is comparable to in vitro exposure (Dizentrics)
Biomarker OPERRA Workshop 2015, Gomolka
Cell nucleus
P Y
1. antibody
2. antibody Y
Principle of the GammaH2AX-Test
Biomarker OPERRA Workshop 2015, Gomolka
0 Gy
0.5 Gy
3 Gy
0
20
40
60
80
100
Fre
qu
en
cyt
in %
0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 40<
Number of gammaH2AX-foci
0Gy 8Gy 15min 8Gy 4h 8Gy 24h
Microscopical Analysis Number of GammaH2AX-Foci in correlation to dose and time
Biomarker OPERRA Workshop 2015, Gomolka
Vandervoorde et al. accepted
Sensitivity of automatic and manual scoring
0,00
0,50
1,00
1,50
2,00
2,50
3,00
3,50
4,00
4,50
5,00
0,000 0,010 0,020 0,030 0,040 0,050 0,060 0,070 0,080 0,090 0,100
foci
dose in [Gy]
No
Integer
manual
Biomarker OPERRA Workshop 2015, Gomolka
0 Gy 0.04 Gy 1.0 Gy
Initial radiation damage (30 min) in different age groups
Biomarker OPERRA Workshop 2015, Gomolka
Damage after 24 h repair in different age groups
0 Gy 0.04 Gy 1.0 Gy 0.04 Gy 1.0 Gy
Biomarker OPERRA Workshop 2015, Gomolka
at dose ... Adults (A) Children (C) Cord Blood (N)
BfS STUK BfS STUK BfS STUK
0 mGy 3/1201 2/1200 3/1002 0/1000 1/1100 0/1100
41 mGy 7/1205 4/1139 3/1002 2/1000 3/1101 3/1100
978 mGy 144/1200 150/1200 193/1000 177/1000 232/1100 188/1100
Cells analysed (BfS and STUK)
Biomarker OPERRA Workshop 2015, Gomolka
Increased numbers of dicentrics in children and cord blood
0
5
10
15
20
25
0 0.04 1dose [Gy]
dic
/100 c
ell
s adult (n = 12)
umbilical cord blood (n = 11)
children (n = 10)
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0 0.04
Biomarker OPERRA Workshop 2015, Gomolka
Kinder Erwachsene
Anzahl Dizentrischer/Zelle
a b
Anzahl ungeschädigter Zellen
c d
Relative Risk for children
Biomarker OPERRA Workshop 2015, Gomolka
Summary
Increased cellular radiation sensitivity in male children from 0-5 years of age
For Umbilical Cord Blood also confirmed by Bakhmutsky 2014
Biomarker OPERRA Workshop 2015, Gomolka
Summary
Increased cellular radiation sensitivity in male children from 0-5 years of age
For Umbilical Cord Blood also confirmed by Bakhmutsky 2014
Dicentric assay is the biomarker of choice!
GammaH2AX highly sensitive but not for age related radiation sensitivity
Biomarker OPERRA Workshop 2015, Gomolka
Future Research
What is going on in the low dose range?
Are there sex differences?
Definition of the exact age window?
Biomarker OPERRA Workshop 2015, Gomolka
Thanks to the partners
• Nabelschnurblut
TUM (Frauenklinik)
Dr. med. Markus Niemeyer
LMU (Klinik und Poliklinik-Großhadern)
PD Dr. med Uwe Hasbargen
• Blut von gesunden Kindern
Dr. med Hans-Joachim Kirlum
Kinderchirurgie in derAu
• CT-Bestrahlung
LMU (Klinik und Poliklinik für Strahlentherapie – Großhadern)
Prof. Belka
Peter Lang, Klement Neumaier
• Statistik
BfS (AG-SG1.3)
Dr. Linda Walsh
Universitätsmedizin Göttingen
Mag. Albert Rosenberger