RADIOBIOLOGY AND RAD PROTECTION CD #5
SOMATIC EFFECTS 2006 RT244 wk 7
2 – WHEN CELLS ARE MODIFIED BY BEING EXPOSED TO
RADIATION - INCREASE PROBABILITY OF CARCINOGENESIS
(CANCER FORMING)
NO THRESHOLD
When somatic or nonreproductive cells are exposed to ionizing
radiation, there is an increase in carcinogenesis – the severity of
cancer does not depend on the dose. 10 rads or 100 rad – the
cancer is no more severe – but the probability that cancer will
develop is increased.
3- Marie Curie and her daughter photo
4 – MARIE CURIES HISTORY OF XRAY DERMATITS ( RED DRY
SKIN)TO HANDS - SEEM TO STOP AFTER A PERIOD OF TIME –
THEN WOULD RECOVER – BUT CANCER IS SLOW TO DEVELOP
AND MAY NOT APPEAR FOR MANY YEARS ( Mr. Hawk’s hand)
5 - CAUSES OF CANCER – uncontrolled growth and spread of
abnormal cells
Cancer is the end results after a series of events that occur in a cell
Exposure to carcinogens – increase the risk of getting cancer.
5% of cancers due to exposure to occupational
CHEMICALS – SMOKING 2X HIGHER of dieing from cancer
UV LIGHT – 600,000 SKIN CANCERS
6 – Cells undergoes mutation – daughter cells contain mutated genes
–
continue to replicate –
Leukemia – grows and crowds out the good cells
9 – Shows how severed fragments of a chromosone combines with
other chromosome – Some genetic information may be lost – a new
gene may be formed that will develop into a cancer cell
RADIOBIOLOGY AND RAD PROTECTION CD #5
SOMATIC EFFECTS 2006 RT244 wk 7
13 –
How the cancer is produced mayu affect the type of cancer – but
does not affect the quality of the cancer
A cancer caused by a chemical agent is no different than a cancer
caused by irradiation
When the cancer is caused by ionization – it does not show
immediately – there is a delay known as the latent period – this can
last for many months or many years
Different cancers have different latent periods.
Leukemia has on the shortest latent periods
CANCER HAS A LATENT PERIOD BEFORE IT SHOWS UP =
LEUKEMIA HAS THE SHORTEST PERIOD
BOMBING VICTIMS from Japan – cases of leukemia began to
appear within a few years - peak period was 7-12 years
(Although these cases appeared at about the same time (age) that
they would normally appear) The exposure to radiation did not
change the time when the leukemia appeared.
# 16 - RISK OF DEATH FROM WORKING IN RADIATION
Radiographers would not be exposed to these levels
#20 – Chart Death from Various Causes
CHART (RADIATION IS 1/100,000) TO 100MRAD/yr
Technologist monitored and protected – doses under 50msv/yr
SLIDE # 21 (LOOK AT THESE FOR PATHOLOGY CLASS)
#21 SOLID TURMOR – 20 TO 50 YEARS
BREAST – LUNG THYROID & BONE
#22 – Leukemia are a group of cancers in the blood forming tissues
About 3% of cancers – but most common type in children
#27 – Breast Cancer (1/9 cancers)
#28 – 3 groups studied of how radiation increases the risk of breast
cancer
-Female survivors of atomic bombing 12,000 women 10 rad or
more
risk of cancer 4 X higher chance)
RADIOBIOLOGY AND RAD PROTECTION CD #5
SOMATIC EFFECTS 2006 RT244 wk 7
- TB Wards in Nova Scoita and Massachusetts – multiple
radiographic exams = 4 – 20 rad) (some women had over
100 exams) 10 X higher chance of developing breast cancer
- Second study of these women showed that when
undergoing fluoro procedures for TB – the POSITIONING of
the patient greatly reduced their risk
# 29 Lung Cancer - leading cancer killer
Smoking the leading cause of lung cancer – the chemicals in
the smoke can cause an alteration in the DNA base
Radon in mines another cause for lung cancer
# 30 Uranium Miners Lungs
Radioactive gas – RADON – a decay product
3000 rad 8:1 risk in cancer
smokers 20:1 risk
#31 Bone Cancer - radium dial watch painter – injested radium
reacted with calcium and deposited in bones
122:1 risk (Pelvis, Femur and Mandible)
Radium (alpha and beta particles)
#32 Skin Cancer – overexposure to the sum (Latent period 5 – 10
years)
Radiation induced – seen in early years
#34 – Radiation Risk Chart
Radiation induced cancers for a dose of 0.1 sV 10 rems