The Pursuit of Excellence in Radiation Safety

Darrell R. Fisher
President, Health Physics SocietyHome: Richland, Washington2Home: Richland, Washington

3Home: Richland, Washington• Population: 55,000• Site of former Atomic Energy Hanford Works

4

Richland: Home to WNP2Columbia Generating Station: 1,170 MWe
GE BWR-5 using a Mark II containment structure5

An honorable profession
Dedicated to excellence in radiation safety
 Protecting the health and safety of the general public,
radiation workers, and hospital patients Advancing standards for excellent practices
 Performing accurate radiation measurements
 Interpreting measurement data honestly
 Developing academic programs and helping students

Multidisciplinary scientists
Health physics combines excellence in multiple specialties:
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nuclear physics
radiation biology
medical radiology
radiochemistryradiopharmaceutical sciencesmaterials sciences
mathematics and biostatistics
nuclear engineering
environmental sciences
occupational hygiene
electrical engineering and instrumentation

Addressing difficult challenges
 We deal with radiation emergencies
 Our broad science backgrounds and passion for technicalaccuracy:• help us put into proper perspective the relative
magnitude of an incident,• provide us with methods for making correct radiation
measurements and analyzing data, and• help us to determine engineered solutions for site
recovery and waste management, containing andshielding radioactivity, packaging, transportation, anddisposal.

We apply correct scientificprinciples to our work
Using correct measurements, models, and computer
software• Environmental transport of radioactive materials• Internal and external radiation dosimetry

A0A1V1A2λ1λ2A3V2A4λ3λ4We encourage academic programs toeducate and train the next generation
We support education in the radiation sciences
 Elementary, middle school, and high school studies
 College and university education

We balance our perspectives onradiation risks and benefits
Our scientific perspective of radiation risks and healthdetriment, judged against the societal benefits of nuclear
technologies, engender credibility and facilitate effective
communication when dealing with government officials,
the news media, and the publicrisks

benefits

We learn to communicate
effectively with the news media
We must be able to provide simple, yet highly credibleanswers to difficult questions from news reporters and TV
and radio journalists

Pseudo-scientists and impostors
In the process of serving our respective
communities, we encounter many imposters
who compete for recognition and authority:••••

the uncredentialed or pseudo-scientists
critics and fault-finders
activist organizations
cross-overs from unrelated specialty
fields in academia

Case study: Safecast™
Safecast™ is a global project to build a sensor networkand map radiation levels
Safecast™ uses static and mobile sensors actively
deployed near the Fukushima exclusion zone andelsewhere in Japan

Source: http://blog.safecast.org

Case study: Safecast™
Radiation detectors:Inspector Alert (InternationalMedcom); uses a 2-inch
pancake sensor

bGeigie: an Inspector
connected to recording
electronics that log counts
tagged with GPS coordinatesand saved to a memory card

Case study: Safecast™
With pancake probe, this
instrument was designed to detectspot contamination (cpm) Not good for environmental
monitoring or for above-ground(1-2 meter) in-air gamma
exposure rate monitoring From the manufacturer’s
Operating Manual: “TheInspector Alert’s reading inmR/hr may not be accurate”

Case study: Safecast™
Radiation detectors:
Thermo Scientific RadEye™ PRD/PRD-ER Personal
Radiation Detector
 Portable, detects and localizes radiation
sources, but does not identify
radionuclides or provide personnel
dose-rate information;
 Not designed for general environmental
monitoring

Personal viewpoint1) the G-M counter with pancake probe is not right formeasuring low-level environmental gamma radiation
because it is highly insensitive (small detector) and doesnot provide accurate information about the ambient
gamma dose rate2) With so many excellent options available from radiation
detector manufacturers, why didn't Safecast choose anappropriate measurement technology?

Preferred alternatives (environmental)
1. Large-volume, energy compensated Geiger-Muller
detector with scaler and timer
2. High-pressure ion chamber with scaler and timer
3. Energy-compensated proportional counter with scalerand timer
4. Large-volume scintillation detector withscaler and timer

References: UK Health and Safety Executive, Information Sheet; Ionizing
Radiation Protection Series #7; Knoll, Glenn F (1999), Radiation Detection
and Measurement (3rd ed.). New York: Wiley.

Personal viewpoint
The Thermo Scientific™ Wide Range Gamma Detector(proportional counter) is well-suited for environmental
monitoring
It uses a Natural Background Rejection method todiscriminate between normal background gamma radiation
and artificial gamma radiation

http://www.thermoscientific.com

The professional health physicist• Educated and trained at an accredited college
or university, with advanced degrees (M.S., Ph.D.)• Certified in health physics• Several years field experience• Reads and understands the radiation protection literature• Belongs to an IRPA-affiliated professional society• Attends and participates in scientific meetings• Understands radiation protection standards

Addressing technical problems• All problems in radiation safety have solutions• Radiation safety issues are best addressed byprofessional health physicists• We have the responsibility to act with integrity,
scientific accuracy, patience, and enduranceWe Are Giving Ourselves Cancer
By RITA F. REDBERG and REBECCA
SMITH-BINDMANNew York Times, Jan. 30, 2014
“Increasingly, we and many other experts
believe that an important culprit may be ourown medical practices: We are silently
irradiating ourselves to death. The use of
medical imaging with high-dose radiation —CT scans in particular — has soared in thelast 20 years….”

What are the risks?
• Is the news article true?
• What are the actual risks of medical diagnostic
radiation?
• How do the risks compare with the medical
benefits?
• How can we better communicate the risks to thepublic?

Unchecked Food Risky in Fukushima
By Mizuho Aoki
The Japan Times, International New YorkTimes, June 17, 2014, Tokyo

Only ninepeople out of30,622
persons
screened had
Cs-137 levels
greater than
50 Bq/kg“Cesium-137 levels among nine participants
ranged from 3,230 to 15,918 becquerels perperson, which corresponds to between 0.07
to 0.53 millisieverts per year . . .
“. . . cumulative exposure of 100 millisieverts
would increase the chance of death bycancer by 0.5 percent….”

Hiroshima-Nagasaki
Atomic Bomb Survivor
Data, U.S. National
Academy of Sciences
Report, Biological
Effects of Ionizing
Radiation(BEIR VII) report,2008.

Hiroshima-Nagasaki Atomic
Bomb Survivor Data, U.S.
National Academy of Sciences
Report, Biological Effects of
Ionizing Radiation(BEIR VII) report, 2008.

Truth: We
do not know
the risk atthese levels!

Dose-response relationships• When we take a closer look, new forms of doseresponse relationships may emerge fromradiobiological data at very low dose
• Example: Large-scale, life-span studies (lung cancer)
of inhaled plutonium-239 in beagle dogs
(Fisher and Weller, Health Phys. 99(3):357–362; 2010)

100

Lung Tumor Incidence, PercentFisher and Weller, Health Phys.
99(3):357–362; 2010
80

Fewer lung cancers at highdose are attributable to thecompeting incidence ofradiation pneumonitis, adeterministic effect that
produces early deaths

60

40

Lung cancer, astochastic effect,
increases withabsorbed dose

20

00

1000

2000

3000

4000

5000

-20
Cumulative Absorbed Dose to Lungs (cGy)

6000

7000

8000

100

Lung Tumor Incidence, Percent

Fisher and Weller, Health Phys.
99(3):357–362; 2010
80

Fewer lung cancers at highdose are attributable to thecompeting incidence ofradiation pneumonitis, adeterministic effect that
produces early deaths

6040

Lung cancer, astochastic effect,
increases withabsorbed dose

20001000

2000

3000

4000

5000

-20
Cumulative Absorbed Dose to Lungs (cGy)

6000

7000

8000

Lung Tumor Incidence, Percent

10080

60

Quadratic dose-response function
Ŷ = 15.36 + 0.0893 (X) – 2.22 (X2)

40r = 0.96

Inhaled plutonium-239 oxide inbeagle dog lungs

2000400

800

1200

1600

2000

-20
Cumulative Absorbed Dose to Lungs (cGy)

2400

2800

Lung Tumor Incidence, Percent

10080slope = 125 lung tumors/ 106 dog cGy
Ŷ = 1.25 x 10-4 (X) + 0.662, r = 0.98

60

40slope = 1360 lung tumors/ 106 dog cGy
Ŷ = 1.36 x 10-3 (X) + 0.0925, r = 0.91

2000500

1000

1500

2000

-20
Cumulative Absorbed Dose to Lungs (cGy)

2500

3000

3500

60

Inhaled plutonium-239 oxide inbeagle dog lungs

Lung Tumor Incidence, Percent

50
40n=830n = 1111n = 2820n = 1010slope = 2390 lung tumors/106 dog cGy
Ŷ = 2.39 x 10-3 (X) - 0.026, r = 0.98

00n = 1650100-10
Cumulative Absorbed Dose to Lungs (cGy)

150200Observations• The linear no-threshold hypothesis may not hold for very
low doses of radiation• The risk coefficients have high uncertainty at very low
doses• We do not know the actual risks of cancer at very low
doses

The pursuit of excellence• In all that we do, we must strive for excellence in thescience and practice of radiation safety• Always learning, we strengthen our technical skills andexpand our knowledge through study, research,
publishing, and participation in scientific meetings

Personal qualities of excellent
health physicists• Objectivity: following the scientific method• Sound and rational decision-making: we act on our skills,
education, knowledge, and experience• Humility: we are still learning, and we are willing to learn• Honesty: needed to gain and retain the trust of thegeneral public and the government• Compassionate: understanding the concerns of patients,
pregnant women, citizens, children, and workers

Summary• The professional health physicist strives for excellence• Always cautious and careful to act, we must act withboldness, courage, and fortitude• As we pursue excellence in our profession,
we will find joy--and our labors will be
rewarded with respect from our peers, themedia, and societySummary

Health physics is a noble and honorable profession

Thank you!
I haveenjoyedvisiting theJapan Health
Physics
Society inNingyo-toge