1. First FRCR Examination in Clinical Radiology Radiation Hazards and Dosimetry John Saunderson Radiation Protection Adviser
2018 version

2. 1b. Radiation Hazards and Dosimetry
Syllabus
1b. Radiation Hazards and Dosimetry
Biological effects of radiations
Risks of radiation
Principles of radiation protection
Justification
Optimisation
Limitation
Kerma, absorbed dose, equivalent dose, effective dose and their units.

3. Wilhelm Roentgen Discovered X-rays on 8th November 1895 15/02/2019
Wilhelm Roentgen - Wurstburg - 8 November fluorescent screen - Crooke's tube - cathode rays.
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4. Henri Becquerel Discovered radioactivity on 26 February 1896
Radioactivity - 4 months later - 26 February Henri Becquerel - rocks - uranium - drawer - photographic plate.
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5. Wrist fracture 1896 Frau Roentgen’s hand, 1895
First radiograph + Colles fracture (radius) (Edwin Frost US 1896)
Wrist fracture 1896
Frau Roentgen’s hand, 1895

6. ( < 10wks after X-rays discovered)
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7. First Radiotherapy Treatment Emil Herman Grubbé
29 January 1896
woman (50) with breast cancer
18 daily 1-hour irradiation
condition was relieved
died shortly afterwards from metastases.
Grubbe - His left hand was amputated in 1929 and he underwent many lesser but nevertheless disfiguring surgeries for multiple cutaneous malignancies.
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8. Dr Rome Wagner and assistant
Doctors - advertising Dr Rome Wagner 1901
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9. First Reports of Injury
Late 1896
Elihu Thomson - burn from deliberate exposure of finger
Reports of injury - in first year - Elihu Thomson was an American (born in Manchester), electrical engineer and inventor whose discoveries in the field of alternating-current phenomena led to the development of successful alternating- current motors. He was also a founder of the U.S. electrical industry Thomson also invented the high-frequency generator (1890), the high-frequency transformer, the three-coil generator, electric welding by the incandescent method, and the watt-hour meter. Thomson Multimedia sold £3 billion in Europe in 2000
Thomson deliberately exposed left index finger for 30 mins a day for several days and provided accurate observations on the resulting erythema, swelling and pain.
March an accidental radiation epilation was observed and reported by Vanderbilt Professor of Physics John Daniel ( ). In February, he had persuaded the Dean of the Medical School to sit for an experimental radiograph of the skull. Three weeks later the dean's hair fell out, a result treated with some levity by those recording the result.
Edison’s assistant - hair fell out & scalp became inflamed & ulcerated
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10. Same year, Thomas Edison was engaged in developing a fluorescent X-ray lamp when he noted that his assistant, Clarence Dally, was so "poisonously affected" by the new rays that his hair fell out and his scalp became inflamed and ulcerated. By 1904 Dally had developed severe ulcers on both hands and arms, which soon became cancerous and caused his early death
By cases of skin damage reported
In the first 5 years, 170 cases of radiation injury were reported. Both Henri Becquerel and Marie Curie suffered grievous burns which were very difficult to heal and which left permanent scars just as a result of handling radium.
In 1898 (or 1900?) Becquerel had suffered a skin burn on his chest caused by a radium vial which he carried in the waistecoat pocket. "I love radium, but the stuff snarls at me"
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11. 15/02/2019

12. Mihran Kassabian (1870-1910) 15/02/2019
Mihran Kassabian ( ) meticulously noted and photographed his hands during progressive necroses and serial amputations, hoping the data collected might prove useful after his death.
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13. Emil Herman Grubbé Jan 1896 X-ray burns to left hand
(29 Jan 1896 first RT)
1926 left hand amputated
Another 92 operations
multiple squamous carcinomas with metastasis
Lost forearm, most of his nose and upper lip and much of his upper jaw
1960 died from pneumonia (85y)
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14. Ironside Bruce was on the staff of Charing Cross Hospital and the Hospital for Sick Children in Great Ormond Street. He was very talented and published widely and his well known book “A System of Radiology; with an Atlas of the Normal” came out in 1907.
The British radiological world was shocked when Bruce died of radiation-induced aplastic anaemia in 1921 at the young age of 42. The outcry resulting from his death resulted in the formation of a radiation protection committee.

15. Mechanisms of Radiation Injury
LD(50/30) = 4 Gy (gray)
280 J to 70 kg man
1 milli-Celsius rise in body temp.
drinking 6 ml of warm tea
Neils Ryberg Finsen 1893 On the influence of light on the skin showed UV caused sunburn and not radient heat. (1903 Nobel Prize for UV treatment of lupus vulgaris)
i.e. not caused by heating, but ionisation.
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16. OH• + e-  OH- (hydroxyl radical) H+ + H2O  H3O+
H2O +   H2O+ + e-
H2O+  OH• + H+
OH• + e-  OH- (hydroxyl radical)
H+ + H2O  H3O+
OH• + OH•  H2O2 (hydrogen peroxide)
O2 + e-  O2- (produces peroxyl radicals)
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17. Law of Bergonié and Tribondeau (1906)
(more a “rule of thumb”)
cells tend to be radiosensitive if they have three properties
1. Cells have a high division rate.
2. Cells have a long dividing future.
3. Cells are of an unspecialized type
(Note, three important exceptions to 3. - small lymphocytes, primary oocytes and neuroblasts)
offers a prediction about the relative sensitivity of two different types of cells or tissues to radiation. Cells tend to be radiosensitive if they have three properties:
Cells have a high division rate. - Cells have a long dividing future. - Cells are of an unspecialized type.
The first condition can be determined by measuring the cell cycle time, i.e., the time between divisions. The second property refers to the fact that many cells go through phases in an overall life cycle. They begin by undergoing many cell divisions (childhood). They then enter a phase in which they stop active division and instead put together the internal structures to function in some usable capacity (adolescence). Finally they enter the last phase where they function fully in the job assigned (adulthood). Cells with a long dividing future would be those in the early immature phases where they are still dividing.
The last criterion, unspecialized, needs further comment. In the biological sense, this means a cell which is capable of specialization, at some future time, into one of several different "adult" cell types. An example might be one of the immature blood cells. Many types of blood cells are "born" unspecialized. Depending on the feedback signal received long after they are formed, they can choose to "grow up" and mature into lymphocytes, or different types of granulocytes. Probably the most unspecialized human cells is a fertilized ovum. From the single cell, daughter cells develop into such widely different mature cells as bone, brain, blood, and fingernails.
The generalization of the Law of Bergonie and Tribondeau is that tissues which are young and rapidly growing are most likely radiosensitive. A very practical application of the Law is given by NRC Regulatory Guide 8.13 which is titled "Instruction Concerning Prenatal Radiation Exposure." This Guide requires that woman of reproductive age be informed of the increased risk of injury of the human fetus from radiation exposure because such a tissue meets all the criteria of the Law of Bergonie and Tribondeau. The human fetus is particularly sensitive in the first few weeks of pregnancy when organs are forming. This is the time period when the woman may not be aware of her pregnancy. Most radiation protection standards recommend that the dose to a developing embryo and fetus be kept below 0.5 rem (5mSv) during the entire nine months of gestation.
small lymphocytes - white bllod cells, primary oocytes - ovum and neuroblasts - embryonic nerve cell
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18. cells are most radiosensitive in late M and G2 phases
Cell cycle
Resistant
Sensitive
Resistant
Sensitive
In general,
cells are most radiosensitive in late M and G2 phases
and most resistant in late S
For cells with a longer cell cycle time and a significantly long G1 phase, there is a second peak of resistance late in G1

19. Relative Radiosensitivity of some Tissues and Organs
Higher
Red bone marrow, colon, lung, stomach, breast, gonads
Medium
Bladder, liver, oesophagus, thyroid
Lower
Skin, bone surface, brain, salivary glands

20. Radiation Quantities and Units
Absorbed dose
Equivalent dose
Effective dose
Kerma and others .
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21. Absorbed Dose (D) Amount of energy absorbed per unit mass [D=d/dm]
1 gray (Gy) = 1 J/kg
Specific to the material, e.g.
absorbed dose to water
absorbed dose to air
absorbed dose to bone.
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22. Typical Values of D
Radiotherapy dose = 40 Gy to tumour (over several weeks)
LD(50/30) = 4 Gy to whole body (single dose)
Chest PA = 160 mGy entrance skin dose .
LD(50/30) kill 50% in 30 days
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23. Equivalent Dose (HT,R)
Absorbed dose to tissue x radiation weighting factor [HT,R = wR.DT,R]
Units are Sieverts (Sv)
All photons, electrons and muons, wR = 1
Neutrons, wR = 5-20 (depending on energy)
Protons, wR = 5
Alpha particles, wR = 20
For X-rays, 1 Gy = 1 Sv
For alphas, 1 Gy = 20 Sv .
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24. Equivalent Dose (HT,R = wR x DT,R)
Note – the weighting factor is for stochastic effects only (i.e. cancer induction or hereditary effects)
Do not use wR for deterministic effects
For deterministic effects, use “Relative Biological Effectiveness” (RBE)
RBE-weighted dose = absorbed dose x RBE (units are gray or sometimes gray-equivalent, Gy-eq)
RBE values may be different for different tissue reactions, dose rates, etc.
e.g. for alpha particles
wR = 20, but
RBE values range from 1 to 8.

25. Effective Dose (E)
Tissue or organ wT (2007)
Gonads 0.08
Red bone marrow 0.12
Colon
Lung
Stomach 0.12
Bladder 0.04
Breast 0.12
Liver
Oesphagus 0.04
Thyroid 0.04
Skin
Bone surfaces 0.01
Brain
Salivary glands 0.01
Remainder 0.12
Sum of equivalent doses to each tissue/organ x organ weighting factors
E = T wT.HT
Units are Sieverts (Sv)
Remainder: e.g. adrenals, brain, upper L intestine, small intestine, kidneys, muscle, pancreas, spleen, thymus, and uterus
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26. Example Abdomen PA 80 kVp 2.5 mm Al filtration 75 cm FSD
35 x 43 cm film
5.4 mGy entrance skin dose
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27. Effective dose = T wT.HT
Tissue or Organ
Ovaries
Testes
Lungs
Stomach
Colon
RBM
Thyroid
Breasts
Oesophagus
Liver
Urinary bladder
Skin
Total bone
Brain
Salivary glands
Average remainder
Effective dose = T wT.HT

28. Example Abdomen PA 80 kVp 2.5 mm Al filtration 75 cm FSD
35 x 43 cm film
5.4 mGy entrance skin dose
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29. Effective dose = T wT.HT
Tissue or Organ
Organ dose, HT (mSv)
Ovaries
0.805
Testes
0.079
Lungs
0.037
Stomach
0.417
Colon
0.718
RBM
0.599
Thyroid
0.000
Breasts
0.007
Oesophagus
0.042
Liver
0.518
Urinary bladder
0.450
Skin
0.386
Total bone
0.697
Brain
Salivary glands
Average remainder
0.472
Effective dose = T wT.HT

30. Effective dose = T wT.HT
Tissue or Organ
Organ dose, HT (mSv)
Weighting Factor, wT
Ovaries
0.805
0.04
Testes
0.079
Lungs
0.037
0.12
Stomach
0.417
Colon
0.718
RBM
0.599
Thyroid
0.000
Breasts
0.007
Oesophagus
0.042
Liver
0.518
Urinary bladder
0.450
Skin
0.386
0.01
Total bone
0.697
Brain
Salivary glands
Average remainder
0.472
Effective dose = T wT.HT

31. Effective dose = T wT.HT
Tissue or Organ
Organ dose, HT (mSv)
Weighting Factor, wT
HT x wT (mSv)
Ovaries
0.805
0.04
0.032
Testes
0.079
0.003
Lungs
0.037
0.12
0.004
Stomach
0.417
0.050
Colon
0.718
0.086
RBM
0.599
0.072
Thyroid
0.000
Breasts
0.007
0.001
Oesophagus
0.042
0.002
Liver
0.518
0.021
Urinary bladder
0.450
0.018
Skin
0.386
0.01
Total bone
0.697
Brain
Salivary glands
Average remainder
0.472
0.057
Effective dose = T wT.HT

32. Effective dose = T wT.HT 0.36 mSv
Tissue or Organ
Organ dose, HT (mSv)
Weighting Factor, wT
HT x wT (mSv)
Ovaries
0.805
0.04
0.032
Testes
0.079
0.003
Lungs
0.037
0.12
0.004
Stomach
0.417
0.050
Colon
0.718
0.086
RBM
0.599
0.072
Thyroid
0.000
Breasts
0.007
0.001
Oesophagus
0.042
0.002
Liver
0.518
0.021
Urinary bladder
0.450
0.018
Skin
0.386
0.01
Total bone
0.697
Brain
Salivary glands
Average remainder
0.472
0.057
Effective dose = T wT.HT
0.36 mSv

33. What’s effective dose for?
Organ doses ranged
from 0.00 mSv (brain, thyroid)
to 2.97 mSv (kidneys)
Effective dose was 0.36 mSv
Risk of inducing cancer  risk of 0.36 mSv to all organs/tissues.
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34. Typical Values of E Barium enema = 7 mSv CT abdomen = 10 mSv
Conventional abdomen = 1.0 mSv
Chest PA = 20 mSv
Annual dose limit for radiation workers = 20 mSv
Annual background dose = 2.5 mSv .
LD(50/30) kill 50% in 30 days
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35. Summary, D, H, E
Energy per kilogramme of material of interest. Can be measured.
Units are Gray. 1 Gy = 1 joule/kg
Often used for organ doses
Absorbed dose, D
Takes into how carcinogenic the type of radiation is
H = wR x D. Units are Sieverts (Sv)
wR = 1 for all X-rays, electrons, beta particles. wR = 20 for alpha particles
Sometimes used for tissue doses (e.g. dose limits to skin and eyes)
Equivalent dose, H
Effective dose, E

36. Kerma (K) Kinetic Energy Released per unit MAss
sum of the initial kinetic energies of all the charged particles liberated by uncharged ionizing radiation per unit mass [K=dEtr/dm]
1 Gray (Gy) = 1 J/kg
Specific to the material, e.g.
Air kerma – (most electronic radiation meters are calibrated in this)
At high photon energies K > D [ at 1000keV e.g. Dair = Kair]
At low photon energies K  D [ at 100keV e.g. Dair = Kair] .
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37. Typical Value of K Typical X-ray set output at 80 kVp
14 mGy per 100 mAs at 75 cm .
LD(50/30) kill 50% in 30 days
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38. Others Dose equivalent (Sv) - superseded by equivalent dose
Effective dose equivalent (Sv) - superseded by effective dose
Ambient dose equivalent (Sv) - dose a particular depth (often used for personal dosimeter results)
Dose area product (Gy.cm2) - dose x field size
Exposure (R or C/kg) – electrical charge produced in 1 kg of air
Collective dose (manSv) - effective dose x number of people exposed .
DAP - barium enema 7-80 Gy.cm2
UK annual collective dose for
for chest X-rays manSv
for cadiovascular interventional radiology = 904 manSv (4.7%)
angiocardiology 1076 manSv

39. Old Units 100 rad = 1 Gy = 100cGy 100 rem = 1 Sv 100 R  0.9 Gy
Beware, eg.
“Patients treated with strontium-90 delivered in significantly higher doses (up to 2,000 Gy) than in the epimacular brachytherapy procedure described here (24 Gy dosage), showed no acute or late morbidity, even after 3 or more years.[Smith et al, Parvani et al, Wesberry et al]”
WRONG - 2,000 rad (20 Gy)
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40. Two Types of Radiation Effect
Back to the radiation effects
Two Types of Radiation Effect
Tissue reactions
sometimes called “deterministic effects” or “non- stochastic effects”
Example of epilation caused by high dose
CT fluoroscopy procedure
Stochastic effect (“chance effects”)
somatic (effects the exposed individual)
hereditary (effects the progeny of the exposed individual) 40

41. Deterministic Effects (tissue reactions, non-stochastic effects)
Caused by significant cell necrosis
Not seen below a threshold dose
below thresholds, too few cells killed to affect organ function
Above the threshold, the bigger the dose, the worse the effect
e.g. for skin, 2 Gy threshold for transient erythema, 20 Gy threshold for secondary ulceration
May take weeks or even months to manifest
e.g. transient erythema appears a few hours after exposure, but dermal necrosis may take 3 months
Do not accumulate over long term
e.g. if 1.5 Gy to skin today and 1.5 Gy in a few months’ time then erythema threshold is not exceeded as sub-clinical skin damage is repaired in the time between the two exposures. However, 1.5 Gy now and 1.5 Gy an hour later will exceed threshold as insufficient time for skin to repair damage.

42. Thresholds for tissue reactions
Normally expressed as dose estimated to result in 1% incidence of tissue reactions
Time to onset of effect varies, and can be many months
Note, the radiation sensitivity varies between individuals. Skin reactions can begin at 2 Gy for some, but for most not below 5 Gy.
Rapidly dividing cells are generally more sensitive to radiation as most vulnerable during M and G2 phases of the cell cycle (which is why radiotherapy works – generally speaking rapidly dividing cancer cells damaged more by radiation than healthy cells)

43. Thresholds for one off exposures
From 2012 ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context

44. From 2012 ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context
Continued on next slide . . .

45. . . . continued from previous slide
Continued on next slide . . .

46. . . . continued from previous slide

47. From FDA, Sept 1994, “Avoidance of serious x-ray induced skin injuries to patients during fluoroscopically-guided procedures”
The higher the dose above the threshold, the worse the injury

48. Example of Radiation Injury in Cardiology
40 year old male
coronary angiography
coronary angioplasty
second angiography procedure due to complications
coronary artery by-pass graft
all on 29 March

49. Fig. A
6-8 weeks after multiple coronary angiography and angioplasty procedures

50. Fig. B
16 to 21 weeks after procedure, with small ulcerated area present

51. Fig. C
18-21 months after procedure, evidencing tissue necrosis

52. Fig. D Close up of lession in Fig. C
From injury, dose probably in excess of 20 Gy .

53. • • • • • •
Fig. E
Appearance after skin grafting procedure .

54. • • • • • •
75-year-old woman with 90% stenosis of right coronary artery. Photograph of right lateral chest obtained 10 months after percutaneous transluminal coronary angioplasty shows area of hyper- and hypopigmentation, skin atrophy, and telangiectasia (poikiloderma)

55. • • • • • •
56-year-old man with obstructing lesion of right coronary artery. Photograph of right posterolateral chest wall at 10 weeks after percutaneous transluminal coronary angioplasty shows 12 x 6.5 cm hyperpigmented plaque with hyperkeratosis below right axilla

56. • • • • • •
49-year-old woman with 8-year history of refractory supraventricular tachycardia. Photographs show sharply demarcated erythema above right elbow at 3 weeks after radiofrequency cardiac catheter ablation

57. • • • • • •
48-year-old woman with history of diabetes mellitus and severe coronary artery disease who underwent two percutaneous transluminal coronary angioplasties and stent placements within a month. Photograph of left mid back 2 months after last procedure shows well-marginated focal erythema and desquamation

58. • • • • • •
69-year-old man with history of angina who underwent two angioplasties of left coronary artery within 30 hr. Photograph taken 1-2 months after last procedure shows secondary ulceration over left scapula

59. To prevent deterministic effects
Keep skin dose below 2 Gy
Keep eye dose below 500 mGy .

60. 2012 ICRP recommendations ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context (ICRP Publication 118)
Mostly no significant change to previous threshold doses, but
Some evidence for a threshold acute dose of about 0.5 Gy (or 500 mSv) to the heart and cerebrovascular system for both cardiovascular disease and cerebrovascular disease (1% incidence)
For cataracts in the eye lens induced by acute exposures, recent long term studies, indicate threshold around 0.5 Gy (previously 5 Gy).

61. Stochastic Effects Caused by cell mutation leading to
cancer or
hereditary disease
Current theory says, no threshold
The bigger the dose, the more likely effect.
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62. ICRP risk factors (International Commission on Radiological Protection, ICRP Publication 103, 2007)
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63. ICRP definition of "detriment"
The total harm to health experienced by an exposed group and its descendants as a result of the group’s exposure to a radiation source.
Detriment is a multidimensional concept. Its principal components are the stochastic quantities:
probability of attributable fatal cancer,
weighted probability of attributable non-fatal cancer,
weighted probability of severe heritable effects, and
length of life lost if the harm occurs.
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64. ICRP risk factors (International Commission on Radiological Protection, ICRP Publication 103, 2007)
P(n  1) = 1 - e-(E x risk factor)
If E x risk << 1 then P(n  1)  E x risk
5.5 x 10-5 per mSv  1 in 18,000 detriment
(Previous ICRP60 gave risk of fatal cancer
5.0 x 10-5 per mSv  1 in 20,000 chance).
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65.  1 in 20,000 risk Risk of fatal cancer from 1 mSv
Risk of fatal car accident in UK in 1 year
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66. Evidence of Stochastic Effects
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67. 15/02/2019 6 Aug 1945 Hiroshima 9 Aug 1945 Nagasaki
70,000 died immediately at H, 200,000 within 4 months
It was realised that with the development of a nuclear industry, large numbers of people, other than in the medical profession, were going to be exposed to doses of radiation, and new dose limits were needed.
About 100,000 who received over 200 mSv survived. The bomb victims were studied.
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68. 15/02/2019 70,000 died immediately at H, 200,000 within 4 months
It was realised that with the development of a nuclear industry, large numbers of people, other than in the medical profession, were going to be exposed to doses of radiation, and new dose limits were needed.
About 100,000 who received over 200 mSv survived. The bomb victims were studied.
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69. Radiation Effects Acute radiation syndrome
Including vomiting, diarrhea, reduction in the number of blood cells, bleeding, epilation (hair loss), temporary sterility in males, and lens opacity (clouding )
Late 1940’s Dr Takuso Yamawaki noted an increase in leukaemia
20% of radiation cancers were leukaemia (normal incidence 4%)
Incidence peaked at 6-8 years
Solid cancers – excess seen from 10 years onwards.
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70. Life Span Study 111,917 persons followed up from 1958
At the end of 2009
37.7% (42,138) still alive
22,538 cancer deaths (1 in 3 deaths)
 10% of these attributable to radiation
(Note – a radiation induced cancer is indistinguishable from a “natural” cancer)
21 out of 800 in utero with dose > 10 mSv severely mentally retarded individuals have been identified
No increase in hereditary disease

71. Life Span Study
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72. (i.e. > 5 mSv or within 2.5 km of the hypercentre)
Cancer deaths between 1950 and 1990 among Life Span Study survivors with significant exposure
(i.e. > 5 mSv or within 2.5 km of the hypercentre) 2
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73. 15/02/2019

74. Atom Bomb Survivors (LSS) results & ICRP recommended risk factor
←1 in 20 risk
← →
↑ 1 Sv (=1000 mSv)
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Linear Non-Threshold (LNT) model

75. Kotaro Ozasa et al, Studies of the Mortality of Atomic Bomb Survivors, Report 14, –2003: An Overview of Cancer and Noncancer Diseases, RADIATION RESEARCH 177, 229–243 (2012)
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76. Data Sources for Risk Estimates
North American TB patients - breast, thyroid, skin
German patients with Ra bone
Euro. Patients with Thorotrast - liver
Oxford study - in utero induced cancer
Atomic bomb survivors - leukaemia, lung, colon, stomach, remainder .
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77. 74 diagnoses with leukaemia and 135 with brain tumours
Pearce et al, Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study, Lancet Aug 4; 380(9840): 499–505.
176,000 patient
74 diagnoses with leukaemia and 135 with brain tumours
Relative risk of leukaemia and brain tumours in relation to estimated radiation doses to the red bone marrow and brain from CT scans (A) Leukaemia and (B) brain tumours.
Dotted line is the fitted linear dose-response model (excess relative risk per mGy). Bars show 95% CIs.
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78. Changes to eye dose threshold
Threshold for 1% incidence of cataracts was thought to be 500 mSv acute or 5,000 mSv chronic exposure
Old lens dose limit (pre 2018)
for classified persons = 150 mSv/y equivalent dose
Other staff, limit 45 mSv/y
New 2012 recommendation threshold is 500 mSv chronic
New lens limit from 1st Janaury 2018 is now
Classified person = 20 mSv/y
1/25th of new threshold
New other staff limit will be 15 mSv
1/33rd threshold,
1/3rd old limit

79. Doses in Interventional Radiology Taken from “Real-time quantification and display of skin radiation during coronary angiography and intervention”, den Boer A, et al., Oct 2001
332 patients
Gy.cm2 dose-area product
mSv effective dose
1: :1100 risk of inducing fatal cancer .
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80. Hereditary Effects Observed in animal experiments
Not observed in A-bomb victims
ICRP 103 Detriment for severe hereditary disease = 0.2 x 10-5 per mSv (i.e in 20,000 per mSv).
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81. Probability of fatal cancer (Atom bomb “survivors”)
Risk per million per mGy
i.e. children risk  3 x adult risk

82. Radiation Risks to the Foetus Deterministic Effects
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83. Radiation Risks to the Foetus Stochastic Effects
The Oxford Study of Childhood Cancers (OSCC) estimated that 25 mGy in utero doubles the risk of childhood cancer
The natural risk of childhood cancer (UK) is 1 in 500 (more than half survive)
So radiation risk about 1 in 13,000 per mGy
(c.f. risks for adults about 1 in 24,000 per mSv)

84. Fetal Doses from Medical Exposure (mGy)
OSCC - 25 mGy doubles natural risk
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85. Fetal Doses from Medical Exposure (mGy)
OSCC - 25 mGy doubles natural risk

86. 15/02/2019
during-diagnostic-medical-exposures-ionising-radiation

87. 15/02/2019

88. ICRP 103 (2007)
The Commission considers that it is prudent to assume that life-time cancer risk following in-utero exposure will be similar to that following irradiation in early childhood,
i.e., at most, about three times that of the population as a whole.
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89. 15/02/2019
Do not adjust your set

90. 2007 Recommendations of the International Commission on Radiological Protection ICRP Publication 103

91. Principles of Radiation Protection
Justification
Optimisation
Limitation

92. The Justification of a practice
“Any decision that alters the radiation exposure situation should do more good than harm.”
i.e. must be a net benefit.

93. The Optimisation of Protection
“The likelihood of incurring exposures, the number of people exposed, and the magnitude of their individual doses should be kept as low as reasonably achievable, taking into account economic and societal factors .”
ALARA
as low as reasonably achievable .

94. Individual Dose and Risk Limits
“The total dose to any individual from regulated sources in planned exposure situations other than medical exposure of patients should not exceed the appropriate limits recommended by the Commission.”
Prevent deterministic effects
Limit risk of stochastic effects to acceptable level.

95. ICRP’s Three Types of Exposure
Occupational
Medical
Public

96. Occupational Exposure
“exposures incurred at work as a result of situations that can reasonably be regarded as being the responsibility of the operating manager.”
20 mSv a year effective dose (averaged over 5 years, but <50mSv in a single year)
20 mSv a year to lens of eye
(Note – changed from 150 to 20 mSv by ICRP 118 in 2012)
500 mSv a year to 1 cm2 of skin, hands and feet
Fetus: from declaration of pregnancy
1 mSv to the embryo/fetus.
Not K-40 in body, cosmic rays, from rocks
But YES for radon build up if ventilation can help
YES for uranium mining, processing NORMs, etc.

97. Medical Exposure
“exposures incurred by individuals as part of their own medical diagnosis and treatment .”
“and individuals helping in the support and comfort of patients undergoing diagnosis and treatment (not occupationally) . . .”
No dose limits apply
Consider dose constraints.
Not K-40 in body, cosmic rays, from rocks
But YES for radon build up if ventilation can help
YES for uranium mining, processing NORMs, etc.

98. Public Exposure Limits apply to exposures from human activities
1 mSv a year effective dose
in special circumstances, average over 5 years
15 mSv a year to lens of eye
50 mSv a year to 1 cm2 of skin.
Not K-40 in body, cosmic rays, from rocks
But YES for radon build up if ventilation can help
YES for uranium mining, processing NORMs, etc.

99. End