Radiocarcinogenesis Flashcards
What countries do you think have conducted nuclear weapon tests?
PINK FUS
What are our sources of radiation information?
Nuclear weapons Power Station incidents Military powered vehicle incidents Medical Imaging Occupational Natural environment
Rank the radiation exposure events in terms of severity
Three mile island single PA chest MRT annual occupational exposure Single supine abdomen Chernobyl survivors Hiroshima Bomb survivors
Describe the effect of radiation induced cancers
When a reproductive cell is radiated it can either be damaged and still divide or it can be damaged and it dies. The daughter cell which is damaged can be mutated or it can undergo cell death.
Define radioleukemogenesis
induction or production of leukemia due to radiation
What is the latency peak associated with leukaemia. What are the sources of leukaemia? What is the ratio of death at what exposure associated with leukaemia?
10 year latency peak
Sources
Radiotherapy Ankylosing Spondylitis
Radiotherapy Hyperthyroidism
50 / 10^6 / 10 mSv
What are the sources of thyroid cancer? What is the ratio of death at what exposure associated with thyroid cancer?
Sources
Japanese A Bomb Survivor Cohort studies
Marshall Islanders
Ann Arbour and Rochester enlarged thymus programmes
(Occurrence) 50 - 150 / 10 6 / 10 mSv
(Fatality) 8 / 10 6 / 10 mSv
What are the sources of bone cancer? What is the ratio of death at what exposure associated with bone cancer?
Sources
Radium Clock, watch and dial face painters
5 / 10 6 / 10 mSv
What are the sources of lung cancer and the fatalities?
Sources
Uranium Miners. Bohemia, Czech republic
85 / 10 6 / 10 mSv
What are the sources of breast cancer and the fatalities?
Sources
Japanese A-bomb Survivor Cohort Studies
1940 – 1950. Radiation therapy treatment for post partum mastitis
1930 – 1952. TB Canadian Fluoroscopy Cohort study
20 / 10 6 / 10 mSv
What are the fatalities and the risk associated with Radiation Induced Cancer?
Collectively
500 / 10 6 / 10 mSv
Radiation workers risk estimated to be 400 / 10 6 / 10 mSv
What are the sources for acute and chronic radiation effect knowledge and what are the magnitudes of the effect?
Sources
US Radiologists
Japanese A bomb Survivor Cohort Studies
Magnitude of the Effect
Acute. 1 – 5 % per sievert
Chronic.
What are the stages of a developing embryo?
Preimplantation stage (conception – two weeks) Organogenesis stage (two – eight weeks) Foetal stage (nine weeks – delivery)
What are the sources to research the effects of radiation on a developing embryo?
Human Sources
Japanese A bomb Survivor Cohort Studies
Therapy patients
Animal Studies
Teratogenic effects Pre and neo natal death Growth retardation Abnormalities Post natal induction of cancer
What is the period limitation for the preimplantation stage?
Period from conception until fertilised egg attaches to the uterus wall (generally two weeks).
What is irradiating an embryo at the preimplatation stage?
Irradiation at this stage “all or nothing” effect.
Pre-natal death most significant risk.
Embryos that survive, usually develop normally.
No birth defects were found in Japanese A bomb survivors as a result of irradiation during this stage.
A dose as low as 0.05 Gy can kill at this stage.
LD50/30 is 1 Gy at this stage (based on studies in mice)
What occurs during the organogenesis stage?
Organogenesis – development of major organs
What is the effect of radiation during the organogenesis?
Pre-natal death reduced rate
Risk due to congenital abnormalities
Growth retardation may recover after birth
Most sensitive at start of period rather than end.
LD50/30 is 1.5 Gy at this stage (based on studies in mice)
Respectively in Weeks 2-5 and 6-8 what happens during organogenesis?
Weeks 2 - 5. Skeletal defects – stunted limbs, polydactyly, oligodactyly
Weeks 6 - 8. CNS defects – anophthalmia, ancencephaly, exencephaly
0.2 Gy can increase abnormalities.
Congenital deformities naturally 6%. Large doses of radiation increase this to 7%
What is the period of the foetal stage?
Period nine weeks onwards
What is the effects of radiation on a developing embryo during the foetal stage?
Incidence of prenatal death and abnormalities is very low
Death as a result of irradiation, often occurs after birth with the newly born developing ARS symptoms
Growth retardation more likely to be permanent
LD50/30 is 2 – 3 Gy at this stage (based on studies in mice)
As the foetus nears delivery, the LD50/30 increases to post natal figures
What is the incidence of neonatal death normally and how much does radiation increase the incidence?
Normal Incidence 25,000 / 106
Radiation incidence. 200 – 500 / 106 / 10 mSv
What is the normal incidence of mental retardation and what effect is it?
Normal Incidence 5,000 / 106
Severe retardation 40% at 1 Gy
Deterministic effect with a suspected threshold of ~0.2 Gy
What is the incidence of childhood fatal cancer normally and how much does radiation increase the incidence?
Normal Incidence 500 / 106
Radiation incidence. 200 – 500 / 106 / 10 mSv
What disease counts for half of the childhood fatal cancers?
Leukaemia accounts for half
How much effective dose per year and over 5 years does a radiation personnel allowed?
An effective dose of 20 mSv per year averaged over any five (5) year period and 50 mSv in any one year.
How much equivalent dose is a radiation personnel allowed in one year?
An equivalent dose of 500 mSv to the skin (at the nominal depth of 7 mg/cm²) averaged over 1 cm², regardless of the total area exposed, in any one year.
How much equivalent dose to any eye is a radiation personnel allowed in one year?
An equivalent dose of 150 mSv to the lens of either eye in any one year.
How much equivalent dose to hands and feet is a radiation personnel allowed in one year?
An equivalent dose of 500 mSv to the hands and feet in any one year.
For radiation personnel woman who declare themselves pregnant what dose are they allowed?
For woman who declare themselves pregnant, a dose of 2 mSv at the surface of the abdomen over the remainder of the pregnancy.
MRT working through pregnancy incidence 510 / 106 (0.051%) (childhood fatal cancer)
Non-radiation personnel and members of the public are allowed an effective dose of?
1 mSv per year
Non-radiation personnel and members of the public are allowed an equivalent dose of what to the skin?
An equivalent dose to the skin of 50 mSv over any 1 cm², regardless of the total area exposed, in any one year.
Non-radiation personnel and members of the public are allowed an equivalent dose of what to the either eye?
15 mSv/ one year
Having an extremity xray increases your chances of cancer by?
1 : 2,000,000
Dose of ~0.01mSv.
Having an lumbar xray increases your chances of cancer by?
Dose of ~2.5mSv. 1 : 8,000
A NZ MRT recieves an average effective dose of?
0.5 mSv per anum
What is the background radiation in NZ?
2 mSv per anum
An extremity xray is equivalent to how much background radiation?
less than 2 days
A lumbar xray is equivalent to how much background radiation?
15 months
Being an MRT shortens your life span by?
12 days less
How does being an MRT affect you having cataracts?
No affect but protective glasses if spend a lot of time in interventional work
Being an MRT increases your risk of cancer by
1 : 40,000
Natural incidence is 1 : 3
What does recent research suggest about leukaemia and occupational exposure?
No link
