Health Risks of Ionizing Radiation: - Clark University

List of Figures
Figure 1-1 Average worldwide exposure to radiation sources; total exposure averages
2.8 mSv per year .....................................................................................................2
Figure 1-2 The evolution of health protection standards for nuclear workers ........................4
Figure 1-3 The atom .................................................................................................................5
Figure 1-4 Types of radiation ...................................................................................................5
Figure 1-5(a) Alpha particle radiation occurs when an unstable nucleus (the parent nucleus)
releases a particle equivalent to the nucleus of a helium atom (2 neutrons
and 2 protons) thus leaving a nucleus with 2 less protons and neutrons (the
daughter nucleus) ....................................................................................................6
Figure 1-5(b) Beta particle radiation occurs when a parent nucleus releases an electron
(this is called a beta particle to differentiate it from the electrons that orbit
the nucleus) .............................................................................................................6
Figure 1-5(c) After a decay reaction, the nucleus is often in an “excited” state. ..........................6
Figure 1-6 Examples of dose-response relationships .............................................................11
Figure 2-1 A bar graph showing average annual natural radiation doses worldwide ............14
Figure 2-2. High background radiation areas around the world ..............................................15
Figure 2-3 A map created by the EPA showing average indoor radon levels by county ........16
Figure 3-1 Average doses from diagnostic radiation exposures .............................................20
Figure 3-2 In the 1950s the panoramic X-ray machine was invented to take a picture
of the whole mouth with just one exposure ..........................................................21
Figure 3-3 Relative risk of myeloid leukemia among adults according to the number
of x-ray exams of the trunk (torso) in the period up to six months before
leukemia diagnosis ................................................................................................22
Figure 3-4 Thyroid cancer SIRs for patients who had been diagnosed for reasons
other than suspicion of a thyroid tumor ................................................................22
Figure 3-5 CAT scans deliver some of the highest doses of medical radiation to
patients. .................................................................................................................23
Figure 3-6 In the late 1940s chest x-rays were used to screen for tuberculosis .....................24
Figure 4-1 The bomb dropped over Nagasaki on August 9, 1945 was called Fat Man .........43
Figure 4-2 A view of the destruction of the city of Hiroshima ..............................................44
Figure 4-3 A view from the air of the bombing of Nagasaki .................................................44
Figure 4-4a These figures show how the radiation exposure of the cities of Hiroshima
and Nagasaki were studied ...................................................................................47
Figure 4-4b These figures show how the radiation exposure of the cities of Hiroshima
and Nagasaki were studied ...................................................................................47
Figure 4-5 ERR estimates for total solid cancer incidence by gender and age at
exposure ................................................................................................................48
Figure 4-6 Incidence ERR by age at exposure for selected cancer sites ................................49
Figure 5-1 A map showing the approximate locations of worldwide nuclear bomb
test sites .................................................................................................................58
Figure 5-2 Military observers shield their faces from the Teapot Test in 1955 ......................59
Figure 5-3 Atmospheric test Grable conducted in 1953 at the Nevada Test Site ..................60
Figure 5-4 Per capita thyroid doses resulting from all exposure routes from all test .............62
Figure 5-5 A nuclear test conducted as part of Operation Crossroads off Bikini atoll
in the Marshall Islands in 1946 .............................................................................63
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