Highest Quality Supplements Since 1980

Life Extension Magazine

<< Back to December 2015

Consumer Reports Discovers Dangers Of CT Scans And X-Rays

December 2015

By William Faloon

William Faloon
William Faloon

The March 2015 issue of Consumer Reports published an in-depth article about the cancer-causing effects of medical X-rays and CT scans. The title of this Consumer Reports article is:

The Surprising Dangers Of CT Scans And X-rays.”1

We applaud Consumer Reports for publishing this expose. It will save human lives. We’re taken aback, however, as to why the word “surprising” was used in the title.

There’s nothing surprising about the striking number of cancer deaths caused by medical imaging procedures like CT scans. These imaging devices emit high amounts of ionizing radiation that damage DNA and create mutations that can lead to cancer.

The National Cancer Institute estimates that at least 15,000 cancer deaths will occur as a result of CT scans performed in 2007.2,3

This same report estimates 29,000 new cancer cases occurred in 2007 alone from CT scan exposure. Since exposure to radiation-emitting imaging procedures has risen approximately 6-fold4 since 1980, the number of excess cancers being caused is potentially astronomical.

What may have prompted Consumer Reports to publish their article was a recent study that looked at people who had CT scans as children and then followed them for almost 10 years. This study found a 24% increased cancer risk from just one CT scan, with each additional CT scan boosting cancer risk an additional 16%. Cancer risk was greater with a younger age of exposure.5 While overall cancer rates in this group were low, the statistical significance was robust, meaning these frightening increases in cancer rates are unlikely to have occurred by chance.

Our earlier warnings about the dangers of radiation from medical diagnostic procedures like CT scans were ridiculed and largely ignored. We hope that the Consumer Reports’ investigative analysis will encourage more patients to stand up to their doctors and question the necessity of exposing their body to cancer-causing radiation. As you’ll read in this article, many X-rays and CT scans performed today should not be done.

Dangers Of CT Scans And X-Rays  

There is not a topic I have more hotly debated with physicians than the danger posed by ionizing radiation emitted from CT scans and X-ray imaging devices.

On a personal level, every doctor I have ever argued this point with has stated that CT scans and X-rays are 100% safe. I rarely violate rules of debate by stating that someone is categorically wrong, but I have never stepped back from declaring that exposing one’s healthy cells to ionizing radiation from medical diagnostic imaging (like CT scans) increases cancer risk.

Life Extension® long ago published the frightening numbers of Americans who are contracting cancer as a result of prior CT scans or X-ray exposure. Medical authorities are now somewhat aware of this data, yet few who prescribe CT scans or X-ray imaging are paying attention to it.

One-Third Of Radiation Scans Are Unnecessary

Each year, there are 72 million CT scans performed in the United States.6 This is up from 3 million in 1980 when CT scans began to be aggressively marketed to doctors.7 CT scans provide superior imaging compared to conventional X-rays, but at the cost of vastly higher doses of ionizing radiation.7

A recent report found that as many as one-third of CT scans and other diagnostics that expose patients to high levels of radiation are being done too frequently.7 We at Life Extension® believe that more than a third of radiation-emitting imaging procedures could be eliminated.

One obstacle we battle when it comes to this debate is physician prescribing practices that are very difficult to change. Doctors were taught in school that radiation from medical diagnostic imaging was very safe and posed no long-term risk to their patients. Throughout their residency and into practice, the idea that ionizing radiation from medical diagnostic imaging is safe, and does not increase long-term cancer risk, is consistently reinforced to physicians, often by radiologists. In addition, physicians are often in the practice of defensive medicine, and order unnecessary imaging tests born out of the fear of litigation.

Especially worrisome is the fact that some physicians have a financial investment in the very medical diagnostic imaging centers to which patients are referred.

Consumer Reports magazine now urges patients to ask if their doctor has a financial interest in a diagnostic imaging center. It should not come as a surprise that when physicians invest in a CT scanner or other radiology equipment, they then have a financial incentive to refer more of their patients for CT scans and other imaging tests.

Consumer Reports urges all patients to question their doctor when a CT scan or X-ray is ordered, as some problems can be managed without powerful doses of radiation.8

Widespread Ignorance Of The Dangers

Widespread Ignorance Of The Dangers  

Consumer Reports conducted a survey and found that only 4% of patients prescribed a CT scan had the knowledge to say “no” to their doctor.1 This prompted one enlightened doctor to state that patients need to take the lead in questioning whether a CT scan or X-ray is necessary.

A 2012 study was done of medical personnel who worked with patients undergoing abdominal CT scans (which often emit the most radiation). This study found that less than 50% understood that these scans could cause cancer.9

Another study revealed only 9% of emergency room physicians said they knew that CT scans increased cancer risk.10

This widespread ignorance amongst professionals on the front lines of medical care is alarming.

Until doctors get up to speed on the risks posted by radiation-emitting imaging devices, patients need to assert control and not capitulate to the exaggerated fears doctors instill to persuade patients to undergo unnecessary CT scans, X-rays, or other diagnostic imaging procedures involving ionizing radiation.

Defending Against Lawsuits

A study presented at the 2011 meeting of the American Academy of Orthopedic Surgeons provided clear evidence of why CT scans and other medical diagnostic imaging tests are being so over utilized.

It turns out that 35% of imaging tests are being done by doctors out of fear of lawsuits.1,11-13 In other words, if sued by a patient (and zealous personal injury attorney) for malpractice, doctors need hard evidence showing the patient was aggressively diagnosed, as well as treated.

How To Reduce Radiation Exposure From Medical Diagnostic Tests

Dangers Of CT Scans And X-Rays  

A partial solution to the widespread overexposure to ionizing radiation is to turn down the amount of radiation emitted from each scan. This can be done because most modern CT scanners can be intensity modulated. This means the dose of radiation needed to obtain a crisp picture of your insides can be greatly reduced based on your body mass and other factors.14

What hurried X-ray technicians have done too frequently is set the dose of radiation at the highest level for all patients, thereby eliminating the time needed to adjust the radiation dose to conform to each individual. This ensures great consistent images at the cost of many times the radiation dose required for most people. As a patient, you should insist that if a CT scan is needed, your body mass be evaluated and the lowest possible dose of radiation be used to obtain the needed images.15,16

A particularly disturbing trend pointed out by Consumer Reports is that children are too often being given adult-sized doses of radiation, which is many times what they need.1 The higher dose directly increases the child’s cancer risk, yet rushed radiology technicians don’t want to bother turning down the radiation intensity. The pressure to put patients on a fast-moving assembly line, with little regard for individualized care, is epidemic throughout today’s hurried and increasingly depersonalized world of mainstream medical practice.

Modern Imaging Saves Lives!

It is important to point out that CT scans save more lives than the cancers they cause.14 The problem is they are being overused and wrongly used in too many cases.

For many diagnostics, ultrasound devices can provide a clear internal image while emitting no ionizing radiation.17-19 MRI (magnetic resonance imaging) often provides a clearer picture than a CT scan for soft tissue,20 but since MRIs cost much more, insurance companies increasingly are refusing to pay for them.21

Those who display outward symptoms of a stroke should insist on an immediate CT scan of their brain so that comprehensive stroke-reversal therapies can be promptly administered to reduce the risk of paralysis or death. CT scans can be done instantly compared to the much longer time it takes for magnetic resonance techniques. (Some hospital ER rooms are equipped to do quick MRI scans for stroke patients.)

When compared to the perils and pain of exploratory surgery, a CT scan is a breakthrough that should be utilized when appropriate.

For cancer patients, the use of multiple whole-body PET/CT scans with enhanced reading techniques provides enormous insight into whether treatments are working or need adjustment. For treatment of difficult and aggressive cancers, the long-term risk from exposure to the radiation from PET/CT scanners is less than the immediate risk posed by the aggressive cancer.22,23

Startling Numbers Of Excess Cancers
Startling Numbers Of Excess Cancers

In 2009, the journal Archives of Internal Medicine published findings showing the potential for adverse effects of ionizing radiation from medical imaging procedures like CT scans.

This study led by the National Cancer Institute used a model of radiation risk over time based on CT scans administered in the year 2007.

The results suggested that CT scans alone may contribute to 29,000 new cancer cases over time, and nearly 15,000 cancer deaths over time assuming 50% mortality.3

My Pain Of Saying No To Dentists

Dentists are adamant about doing annual X-rays and represent the strongest proponents of prophylactic X-rays. Not one dentist I have encountered has ever acknowledged there is any risk posed by these annual X-rays.

I have refused dental X-rays for most of my life despite dire warnings by my dentists that there could be underlying tooth decay. When I developed some pain in my mouth two years ago, I consented to dental X-rays. No abnormality was revealed.

I then went to a medical specialist who said he could prescribe a CT scan of my entire jaw that might detect what was causing my considerable pain. This doctor also cautioned that some people develop a condition called idiopathic oral facial pain in which no underlying cause is detected by a CT scan. (Idiopathic means a disease of unknown origin.)

I declined the CT scan of my jaw and suffered fluctuating pain for almost a year and a half until the pain became so acute that I went back to the dentist for another dental X-ray, which this time revealed a single decayed tooth that was readily treated.

Had I opted for the CT scan, this decaying tooth would have likely been detected much earlier. Of course, very vulnerable parts of my head and neck would have also been exposed to high levels of radiation from the CT scan (much greater than typical dental X-rays).

So I paid a painful price for declining the CT scan of my jaw. I always like to relate real-world events so that readers understand the challenges of determining when to say “no” to a radiation-emitting imaging device. It’s not always an easy decision.

Experts Historically Underestimated Radiation Risks

When radiation was first discovered, doctors were wildly enthusiastic about being able to peer inside the body of a living human.

Thomas Edison
Thomas Edison

Sadly, radiation killed its early pioneers, who had no idea of its dangers.

Even as knowledge of radiation’s lethal properties became apparent, experts consistently underestimated the risks.

One tragic example was an individual named Clarence Dally who intentionally exposed himself multiple times to ionizing radiation from Thomas Edison’s “fluoroscope” invention. Within a few months, Dally began suffering debilitating fatigue, body aches, and multiple burn-like lesions on his hands. These lesions turned out to be cancer that rapidly spread throughout his body. Dally lost both his arms to these malignant lesions, and died a painful death in 1904. Thomas Edison was said to be haunted for the rest of his life by Dally’s cancer and death, and refused to have anything more to do with ionizing radiation.24

PHOTO by Louis Bachrach, Bachrach Studios, restored by Michel Vuijlsteke—United States Library of Congress

Operation Teapot Nuclear Test
Operation Teapot
Nuclear Test

In the 1950s, our federal government routinely conducted above-ground testing of nuclear bombs in the Nevada desert and claimed the radioactive fallout that spread throughout much of the United States was “harmless.” In 2002, the federal government admitted that the radiation emitted from these nuclear weapons tests caused 15,000 American cancer deaths.25 Critics claim this number grossly understates the actual number of cancer deaths.26-28

Photo courtesy of National Nuclear Security Administration / Nevada Site Office

Linus Pauling
Linus Pauling

In the May 2002 edition of Life Extension® magazine, I wrote a tribute to Linus Pauling for his intellect and courage to challenge the federal government’s claim that radioactive fallout was “safe.”29 Dr. Pauling endured endless persecution from government authorities for daring to interfere with the above-ground testing of nuclear bombs. Our government viewed Linus Pauling as a “communist,” when this Nobel Prize-winning scientist was only seeking to protect Americans from the cancers he suspected would be caused by the radioactive fallout.

Dr. Pauling’s tireless efforts eventually resulted in a ban against above-ground nuclear testing by both the United States and Russia, leading him to win his second Nobel Prize.30

Linus Pauling is the only person to ever win two undivided Nobel Prizes. New Scientist magazine ranks Dr. Pauling as one of the 20 greatest scientists to ever live, an honor shared with such figures as Albert Einstein, Charles Darwin, and Isaac Newton.31

RADIATION & HUMAN HEALTH
RADIATION &
HUMAN HEALTH

Yet here we are in 2015, and most of the medical establishment remains oblivious to the documented dangers of radiation-emitting imaging devices. This is despite irrefutable data provided by the late physician-scientist John Gofman, MD, PhD, who worked at the Los Alamos lab inventing nuclear weapons, went on to discover the existence of LDL cholesterol, and then campaigned relentlessly to limit unnecessary exposure to medical sources of ionizing radiation.32-37

John Gofman called me long ago and expressed gratitude that Life Extension regularly warned of the dangers posed by radiation-emitting medical imaging devices. He regretted so few doctors paid attention to the many books he authored documenting higher cancer rates in those exposed to medical radiation.

Are Dental X-Rays Safe?

My dentist makes me sign a waiver of liability because I refuse to have annual X-rays done. Other dentists refuse to treat me unless I capitulate to X-rays whenever they want to do them. There, of course, is considerable clinical value in dentists being able to view under your enamel.

My concern about dental X-rays was partially vindicated when a 2012 study published in the journal Cancer showed that people exposed to annual dental X-rays were twice as likely to develop a brain tumor called a meningioma.38 This type of tumor is usually benign and can be treated with radiation or surgery if needed, but who wants to go through this?

Modern dental X-rays emit less radiation than older devices, and thus may not pose as great a risk for meningioma. However, the authors concluded their 2012 study by warning:

“…there is little evidence to support the use of dental X-rays in search of occult pathoses in the asymptomatic patient or routine dental radiographs at preset intervals for all patients. Although dental X-rays are an important tool in well-selected patients, efforts to moderate exposure to ionizing radiation to the head is likely to be of benefit to patients and health care providers alike.’”38

Said differently, these authors are suggesting that one minimize the number of dental X-rays they are exposed to, which contradicts what is being done in most dentist practices today.

Tribute To Hero Who Uncovered Dangers Of CT-Scans And X-rays
John Gofman
John Gofman, MD, PhD

John Gofman, MD, PhD, was a medical doctor, nuclear chemist, Manhattan Project scientist, co-discoverer of isotopes of uranium and protactinium, the first to separate plutonium in usable quantities, and an early member of the Life Extension Foundation.

Dr. Gofman fought to end policies that allow plutonium and other radioactivity from the nuclear power/weapons fuel chain to be dispersed into the environment. He repeatedly stood up to government pressure to suppress the truth about radiation health dangers.

Dr. Gofman’s accomplishments extend to his groundbreaking research in cardiac medicine, which includes the identification and distinguishing of HDL cholesterol and LDL cholesterol. The Journal of Clinical Lipidology named him the “Father of Clinical Lipidology,” honoring him for discoveries he made decades ago, which are now part of conventional cardiology.43

His tireless work to reduce unnecessary radiation exposure from medical procedures is finally taking hold with Consumer Reports disseminating data that emanated from work that Dr. Gofman initiated many decades ago.

Dr. Gofman firmly believed there is no safe threshold of ionizing radiation one should needlessly be exposed to. He used a linear no-threshold model of radiation risk and argued that far more cases of cancer and other diseases are caused by unnecessary exposure to medical radiation than what the “authorities” admit.44,45

Not everyone agrees with Dr. Gofman’s “linear model of radiation risk” and a debate continues as to whether there is a low level of X-ray exposure that can be accepted as “safe.”

Next time you review your blood test results and see LDL and HDL, remember it was Dr. Gofman’s pioneering research in the 1950s that led to these lipids being included in standard blood test panels to evaluate vascular disease risk.

To read more about this brilliant physician-scientist, just type John Gofman into Google.

Reducing And Repairing DNA Damage Inflicted By Radiation

When I reviewed the number of previous articles we have published about the dangers of ionizing radiation from medical imaging tests and CT scans, I was startled by how much hard data we had uncovered.

Some of our articles describe the potential protection one might obtain by having high doses of specific antioxidants in their body at the time a radiation-emitting imaging procedure is performed.39 Other articles describe the potential for nutrients like blueberry extract to enhance DNA repair so that damage inflicted by medical radiation does not lead to future cancer.40

Some of you might remember an article I wrote last year about a strain of bacteria that was made resistant to 1,000 times the amount of radiation that would kill a human. The mechanism that enabled these bacteria to survive this onslaught of radiation-induced free radical attack was markedly enhanced DNA repair.41,42

The data about the radiation-protecting effects of the nutrients that many of you take daily continues to grow. This means that even if you have needed a CT scan or diagnostic X-ray procedure in the past, if you had these nutrients in your body, you may have gained some degree of protection. Regular intake of blueberry and other plant extracts may have facilitated enough DNA repair to offset the known carcinogenic effects of the radiation. No one knows for certain.

In this month’s issue, we describe some nutrients you want to have in your body prior to being exposed to a radiation-emitting imaging procedure.

I want to again thank Consumer Reports for disseminating information that is almost identical to what we’ve been preaching for decades. While the mainstream media ignores most of what we publish, the Consumer Reports article generated press coverage that I believe will spare some humans from medical radiation-induced cancers.

For longer life,

For Longer Life

William Faloon

Radiation Dose Comparison
Startling Numbers Of Excess Cancers

Different types of medical diagnostic imaging tests pose varying degrees of risk from ionizing radiation exposure.

A brief list of different medical diagnostic imaging tests that utilize ionizing radiation are provided to better identify scans that generate relatively high exposure in comparison to natural background radiation exposure.

Diagnostic
Procedure

Typical Effective Dose (mSv)46

Number Of Chest
X-rays (PA film) For
Equivalent Effective Dose47

Time Period For Equivalent Effective Dose From Natural Background Radiation48

Chest X-ray (PA Film)

0.02

1

2.4 days

Skull X-ray

0.1

5

12 days

Lumbar Spine

1.5

75

182 days

Intravenous (IV)
Pyelogram

3

150

1.0 year

Upper GI Exam
(Barium Swallow)

6

300

2.0 years

Lower GI Exam
(Barium Enema)

8

400

2.7 years

CT Head

2

100

243 days

CT Abdomen

8

400

2.7 years

References

  1. Available at: http://www.consumerreports.org/cro/magazine/2015/01/the-surprising-dangers-of-ct-sans-and-x-rays/index.htm. Accessed September 24, 2015.
  2. Available at: http://www.cancer.gov/about-cancer/causes-prevention/hp-prevention-overview-pdq#section/all. Accessed September 24, 2015.
  3. Berrington de González A, Mahesh M, Kim K, et al. PRojected cancer risks from computed tomographic scans performed in the united states in 2007. Arch Intern Med. 2009 Dec 14;169(22):2071-7.
  4. Fazel R, Krumholz HM, Wang Y, et al. Exposure to low-dose ionizing radiation from medical imaging procedures. N Engl J Med. 2009 Aug 27;361(9):849-57.
  5. Mathews JD, Forsythe AV, Brady Z, et al. Cancer risk in 680,000 people exposed to computed tomography scans in childhood or adolescence: data linkage study of 11 million Australians. BMJ. 2013 May 21;346:f2360.
  6. Available at: http://www.cbsnews.com/news/many-medical-imaging-tests-performed-in-u-s-are-unnecessary/. Accessed September 24, 2015.
  7. Brenner DJ, Hall EJ. Computed Tomography — An Increasing Source of Radiation Exposure. N Engl J Med. 2007 Nov 29;357(22):2277-84..
  8. Available at: http://pressroom.consumerreports.org/pressroom/2015/01/consumer-reports-warns-against-the-risks-of-radiation-overexposure-from-unnecessary-ct-scans.html. Accessed September 24, 2015.
  9. Uri IF. Lack of radiation awareness among referrers: implications and possible solutions. Int J Clin Pract. 2012 Jun;66(6):574-81.
  10. Lee CI, Haims AH, Monico EP, et al. Diagnostic CT scans: assessment of patient, physician, and radiologist awareness of radiation dose and possible risks. Radiology. 2004 May;231(2):393-8.
  11. Available at: http://content.time.com/time/health/article/0,8599,2053354,00.html. Accessed September 24, 2015.
  12. Available at: http://www.sciencedaily.com/releases/2009/02/090202175100.htm. Accessed September 24, 2015.
  13. Available at: http://www.aaos.org/news/acadnews/2011/AAOS13_2_17.asp. Accessed September 24, 2015.
  14. McCollough CH, Primak AN, Braun N, Kofler J, Yu L, Christner J. Strategies for Reducing Radiation Dose in CT. Radiol Clin North Am. 2009 Jan;47(1):27-40.
  15. Hollingsworth C, Frush DP, Cross M, Lucaya J. Helical CT of the body: a survey of techniques used for pediatric patients. AJR Am J Roentgenol. 2003 Feb;180(2):401-6.
  16. Available at: http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm062185.htm#4. Accessed September 29, 2015.
  17. Available at: http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/ucm115357.htm. Accessed September 25, 2015.
  18. Michel F, Brevaut-Malaty V, Pasquali R, et al. Comparison of ultrasound and X-ray in determining the position of umbilical venous catheters. Resuscitation. Jun 2012;83(6):705-9.
  19. Bourcier JE, Paquet J, Seinger M, et al. Performance comparison of lung ultrasound and chest x-ray for the diagnosis of pneumonia in the ED. Am J Emerg Med. 2014 Feb;32(2):115-8.
  20. Available at: http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/ucm200086.htm. Accessed September 25, 2015.
  21. Available at: https://healthcarebluebook.com/. Accessed September 25, 2015.
  22. Available at: http://www.cancer.net/navigating-cancer-care/diagnosing-cancer/tests-and-procedures/integrated-pet-ct-scan. Accessed September 29, 2015.
  23. Gerth HU, Juergens KU, Dirksen U, Gerss J, Schober O, Franzius C. Significant benefit of multimodal imaging: PET/CT compared with PET alone in staging and follow-up of patients with Ewing tumors. J Nucl Med. 2007 Dec;48(12):1932-9.
  24. Kevies BH. Naked to the Bone: Medical Imaging in the Twentieth Century. New Brunswick, NJ: Rutgers University Press; 1997.
  25. Available at: http://usatoday30.usatoday.com/news/nation/2002/02/28/usat-nuke.htm. Accessed September 25, 2015.
  26. Available at: http://www.cnn.com/2002/US/03/01/nuclear.fallout/index.html. Accessed September 25, 2015.
  27. Available at: http://beforeitsnews.com/alternative/2012/05/worst-scandal-in-history-60-million-cancers-from-nuclear-weapons-radiation-2136575.html. Accessed September 25, 2015.
  28. Mangano JJ, Sherman JD. Elevated in vivo strontium-90 from nuclear weapons test fallout among cancer decedents: a case-control study of deciduous teeth. Int J Health Serv. 2011 41(1):137-58.
  29. Available at: http://www.lifeextension.com/Magazine/2011/6/Optimize-Your-Internal-Defenses-Against-Radiation-Exposure/Page-02. Accessed September 25, 2015.
  30. Available at: http://www.nobelprize.org/nobel_prizes/peace/laureates/1962/pauling-bio.html. Accessed September 25, 2015.
  31. Available at: https://www.newscientist.com/article/mg12416944.100-review-feet-of-clay--review-of-linus-pauling-a-man-and-his-science-by-anthony-serafini/. Accessed April 15, 2015.
  32. Available at: http://www.berkeley.edu/news/media/releases/2007/09/04_GofmanObit.shtml. Accessed September 25, 2015.
  33. Gofman JW JW, Lindgren F. The role of lipids and lipoproteins in atherosclerosis. Science. 1950 Feb 17;111(2877):166-71.
  34. Gofman JW. Serum lipoproteins and the evaluation of atherosclerosis. Ann NY Acad Sci. 1956 Nov 16;64(4):590-5.
  35. Gofman JW. Radiation-Induced Cancer from Low-Dose Exposure: An Independent Analysis. 1st ed. San Francisco, CA: Committee for Nuclear Responsibility; 1990.
  36. Gofman JW. Radiation from Medical Procedures in the Pathogenesis of Cancer and Ischemic Heart Disease: Dose-Response Studies with Physicians per 100,000 Population. 1st ed. San Francisco, CA: Committee for Nuclear Responsibility. 1999.
  37. Gofman JW, O’Connor E. Preventing Breast Cancer: the Story of a Major, Proven, Preventable Cause of this Disease. 2nd ed. San Francisco, CA: Committee for Nuclear Responsibility; 1996.
  38. Claus EB, Calvocoressi L, Bondy ML, Schildkraut JM, Wiemels JL, Wrensch M. Dental x-rays and risk of meningioma. Cancer. 2012 Sep 15;118(18):4530-7.
  39. Available at: http://www.lifeextension.com/Magazine/2011/6/Optimize-Your-Internal-Defenses-Against-Radiation-Exposure/Page-01. Accessed September 25, 2015.
  40. Available at: http://www.lifeextension.com/Magazine/2015/4/Blueberries-Boost-Longevity-Beyond-Calorie-Restriction/Page-01. Accessed September 25, 2015.
  41. Available at: http://www.lifeextension.com/magazine/2014/11/creating-immortality-genes/page-01. Accessed September 25, 2015.
  42. Byrne RT, Klingele AJ, Cabot EL, et al. Evolution of extreme resistance to ionizing radiation via genetic adaptation of DNA repair. Elife. 2014 Jan 1;3:e01322.
  43. Brown W. From the Editor-in-Chief. J Clin Lipidol. 2007 May;1(2):97-9..
  44. Available at: http://www.ratical.org/radiation/CNR/synapse.html. Accessed April 20, 2015.
  45. Semendeferi I. Legitimating a nuclear critic: John Gofman, radiation safety, and cancer risks. Hist Stud Nat Sci. 2008 Spring;38(2):259-301.
  46. Mettler FA Jr, Huda W, Yoshizumi TT, Mahesh M. Effective doses in radiology and diagnostic nuclear medicine: a catalog. Radiology. 2008 Jul 248(1):254-63.
  47. Based on the assumption of an average “effective dose” from chest x ray (PA film) of 0.02 mSv.
  48. Based on the assumption of an average “effective dose” from natural background radiation of 3 mSv per year in the United States.