Articles from the Internet: How Safe Or Unsafe Are Medical Imaging Procedures?

Yeong Sek Yee & Khadijah Shaari 

To understand more about the radiation risks from medical imaging, we recommend that you read the following articles posted in the Internet.  Just Google topics like the dangers of medical/diagnostic tests, etc, etc. There are plenty of materials to read. Here are some examples.

1.       Medical Radiation Soars, With Risks Often Overlooked

Radiation, like alcohol, is a double-edged sword. Radiation can reveal hidden problems, from broken bones and lung lesions to heart defects and tumors. But it also has a potentially serious medical downside: the ability to damage DNA and, 10 to 20 years later, to cause cancer. CT scans alone, which deliver 100 to 500 times the radiation associated with an ordinary X-ray and now provide three-fourths of Americans’ radiation exposure, are believed to account for 1.5 percent of all cancers that occur in the United States.

Although the cancer-causing effects of radiation are cumulative, no one keeps track of how much radiation patients have already been exposed to when a new imaging exam is ordered. Even when patients are asked about earlier exams, the goal is nearly always to compare new findings with old ones, not to estimate the risks of additional radiation.

Read more:

2.       Radiation Risks from Medical Imaging

The FDA has put forward its plan to reduce unnecessary radiation exposure from CT scans, nuclear medicine studies, and fluoroscopy.

An individual’s chance of getting cancer from a single scan is small. But because the scans are so widely used, they cause a considerable amount of harm. One study estimated that the CT scans performed in 2007 are related to some 29,000 future cancers.

What are these tests? What are their risks? When do the tests’ benefits outweigh their risks? Here are WebMD’s answers to these and other questions.

How much radiation does a person get from medical imaging studies?

  • Getting a CT scan gives a patient as much radiation as 100 to 800 chest X-rays.
  • Getting a nuclear medicine study exposes a patient to as much radiation as 10 to 2,050 chest X-rays.
  • Getting a fluoroscopic procedure exposes a patient to as much radiation as 250 to 3,500 chest X-rays.

Moreover, doctors may prescribe scans that aren’t medically justified. And since risk from radiation exposure accumulates over a lifetime, certain scans may not be appropriate for people who’ve already had a lot of scans.

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3.       Dangers of Medical Imaging Tests and Procedures

Exposure to medical imaging radiation is a concern in both adults and children. However, radiation exposure in children is of a greater concern because they are more sensitive to radiation than adults. In addition, children have longer life expectancy than adults. With repeated exposure or accumulated exposure to radiation, children may be more likely to develop health problems in the future.

Life time risk of developing cancer increases when a patient undergoes more frequent X-ray exams and at larger doses, according to the FDA. Women who are exposed to the radiation may have higher lifetime risk for developing radiation-associated cancer than men after receiving the same exposures at the same ages.

While experts believe that the risk of developing cancer with radiation exposure is relatively small, radiation exposure through these medical imaging tests should never be taken lightly.

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4.       A Closer Look: The Downside of Diagnostic Imaging

CT and nuclear medicine tests do have a downside, however: they deliver doses of ionizing radiation from 50 to over 500 times that of a standard x-ray, such as a chest x-ray or mammogram. Scientists have raised concerns that such large doses of radiation plus the widespread and increasing use these diagnostic procedures may, in a small but significant way, pose a cancer risk in the general population.

“The use of CT in particular has gone up dramatically, and we’ve drastically lowered the threshold for using it,” said Dr. Rebecca Smith-Bindman, a visiting research scientist with NCI’s Radiation Epidemiology Branch (REB). “There’s a general belief that if you get a CT scan, you must be reasonably sick and must really need it. This is no longer true, and we are increasingly using CT scans in patients who are not that sick. There’s been drift not only in how often we use it but in how we use it.”

“We’ve only talked about the benefits of CT for the past 20 years, without considering any potential harm” she continued.

Research estimated that approximately 29,000 future cancers could be related to CT scans performed in the United States in that year alone, with women being at higher risk than men. About 35 percent of these cancers were projected to be related to scans performed in patients 35 to 54 years old, and 15 percent related to scans performed in children younger than 18. 

The medical community has proposed many ways to reduce radiation exposure from diagnostic medicine without negatively impacting the quality of patient care:

  • Reduce the number of CT exams by using other technologies (such as ultrasound or MRI) in cases where they would provide equal diagnostic quality.
  • Limit the use of CT in healthy patients who would obtain little benefit (such as whole-body CT screening).
  • Limit the use of repeat CT surveillance of patients in whom a diagnosis has already been made, when repeat scanning would lead to little change in their treatment.
  • Track and collect information on radiation exposure for individual patients

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5.       Ionizing Radiation Exposure with Medical Imaging

Medical diagnostic procedures used to define and diagnose medical conditions are currently the greatest manmade source of ionizing radiation exposure to the general population. The risks and benefits of radiation exposure due to medical imaging and other sources must be clearly defined for clinicians and their patients.

Radiation damages the cell by damaging DNA molecules directly through ionizing effects on DNA molecules or indirectly through free radical formation. A lower dose delivered through a long period of time theoretically allows the body the opportunity to repair itself. Radiation damage may not cause any outward signs of injury in the short term; effects may appear much later in life.

Medical ionizing radiation has great benefits and should not be feared, especially in urgent situations. Obviously, using the lowest possible dose is desired. In fact, a central principle in radiation protection is “as low as reasonably achievable.” Therefore, the prescribing physician must justify the examination and determine relevant clinical information before referring the patient to a radiologist. Indications and decisions should reflect the possibility of using non-ionizing radiation examinations, such as MRI or ultrasonography.

Repetition of examinations should be avoided at other clinics or sites.

The International Commission on Radiological Protection (ICRP) estimates that the average person has an approximately 4-5% increased relative risk of fatal cancer after a whole-body dose of 1 Sv.

X-rays (including CT scans) should be ordered judiciously. An article in the New England Journal of Medicine notes that the evidence is “convincing” that the radiation dose from CT scans can lead to cancer induction in adults and “very convincing” in the case of children. Clinicians need to realize that doses from a typical CT scan can range from 6-35 times higher than the dose of a standard chest x-ray examination.

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6.  Doctors Order More Tests when They Benefit Financially: Ask If You Really Need that Test Your Doctor Ordered

Researchers from the Institute for Technology Assessment at the Massachusetts General Hospital Department of Radiology found that there was no mistaking that diagnostic imaging tests were being ordered far more than they deemed necessary. The question that begs to be answered is, “why?”

Many doctors referred their patients to imaging centers that were affiliated with their practice, or were even done by the doctor’s own staff. When a physician has such a close relationship with the provider conducting the imaging study, there is the possibility that the physician will benefit financially from ordering additional imaging studies.

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7.       Radiation Danger from CT and PET Scans

A recent study in the New England Journal of Medicine has found a significant link between radiation exposure and imaging procedures such as CT and PET scans. The use of such technologies has grown from just 3 million in 1980 to 67 million in 2006, and has contributed, some estimate, to upwards of 2% of fatal cancer cases.

Studies have shown that there is little consumer understanding of the risks involved in being subject to such procedures.

Dr. Harlan M. Krumholz proffers that the use of CT scans is increasing because they have become part of our culture. “People use imaging instead of examining a patient; they use imaging instead of talking to the patient,” (New York Times, Study Finds Radiation Risk for Patients, August 27, 2009). For these reasons, imaging technologies have become a common diagnostic tool even when they are not required.

Read more:

8.       Study Finds Radiation Risk for Patients

At least four million Americans under age 65 are exposed to high doses of radiation each year from medical imaging tests, according toa new study in The New England Journal of Medicine. About 400,000 of those patients receive very high doses, more than the maximum annual exposure allowed for nuclear power plant employees or anyone else who works with radioactive material.

Dr. Rita Redberg, a cardiologist and researcher at the University of California, San Francisco, who has extensively studied the use of medical imaging, said it would probably result in tens of thousands of additional cancers. It’s certain that there are increased rates of cancer at low levels of radiation, and as you increase the levels of radiation, you increase cancer.

Dr. Reza Fazel, a cardiologist at Emory University, said the use of scans appeared to have increased even from 2005 to 2007, the period covered by the paper. “These procedures have a cost, not just in terms of dollars, but in terms of radiation risk.”

Read more:

9.      Radiation Exposure from Medical Diagnostic Imaging Procedures

Ionizing radiation is used daily in hospitals and clinics to perform diagnostic imaging procedures.

Which types of diagnostic imaging procedures use radiation?

•  In x-ray procedures, x rays pass through the body to form pictures on film or on a computer or  television monitor, which are viewed by a radiologist. If you have an x-ray test, it will be performed with a standard x-ray machine or with a more sophisticated x-ray machine called a CT or CAT scan machine.

• In nuclear medicine procedures, a very small amount of radioactive material is inhaled, injected, or swallowed by the patient. If you have a nuclear medicine exam, a special camera will be used to detect energy given off by the radioactive material in your body and form a picture of your organs and their function on a computer monitor. A nuclear medicine physician views these pictures. The radioactive material typically disappears from your body within a few hours or days.

Do magnetic resonance imaging (MRI) and ultrasound use radiation?

MRI and ultrasound procedures do not use ionizing radiation. If you have either of these types of studies, you are not exposed to radiation.

There is no conclusive evidence of radiation causing harm at the levels patients receive from diagnostic xray exams. Although high doses of radiation are linked to an increased risk of cancer, the effects of the low doses of radiation used in diagnostic imaging are not known.

Read more:

10.        Radiation Risk of Medical Imaging for Adults and Children

Which kinds of tests are associated with Ionising radiation and which ones are not?

1.  X-rays
X-rays are ionising radiation produced by equipment used in the following types of procedures:

  • Computed tomography (CT)
  • Fluoroscopy (where the image produced by the X-ray beam is made into a moving picture on a TV screen
  • Plain radiology/X-ray film, digital and computed radiography (see  Plain Radiography / X-rays)
  • Mammography (see Diagnostic Mammography)
    • The radiation exposure from having an X-ray, fluoroscopy, mammography or CT examination only occurs while the machine is on.

2.  Magnetic resonance imaging (MRI)
MRI uses strong magnetic fields and radio waves to produce images. It does not use ionising radiation (see Magnetic Resonance Imaging (MRI)).

3.  Ultrasound
Ultrasound uses high frequency sound waves that the human ear cannot detect to obtain imaging information (see Ultrasound).

4.  Nuclear medicine
Nuclear medicine is a medical specialty that involves the administration of a small amount of a radioactive material into the patient. The patient becomes weakly radioactive for a short time and images are made from the radiation given off from the patient (see Nuclear Medicine).

How do I decide whether the risks are outweighed by the benefits of exposure to X-radiation when I have a radiology test or procedure?

  • Ask your doctor about the procedure and how it will help to provide information about your symptom or the presence of disease or injury.
  • Ask your doctor about the risks of the procedure and what the risks would be of not having the procedure, i.e. if your doctor needs the information in order to identify and plan the most appropriate treatment.

While there is a small risk of harm from ionising radiation, there could be a greater risk of not having the information, e.g. failure to detect potentially serious disease that may be easily treated at an early stage but harder to treat or incurable if detected later.

It may also be as beneficial to you to confirm the absence of disease or injury as it is to confirm its diagnosis.

Read more:

11.   Radiation in Medical Imaging Has Its Risks

Almost all medical procedures, including imaging procedures that use radiation, have risks associated with them. Physicians and patients should carefully consider the potential benefits and the risks when considering the use of imaging techniques that involve radiation.

Here are some things for healthcare providers to consider when deciding whether or not an imaging procedure that uses medical radiation is the right choice.

  • What is the purpose of the procedure? For example, is it to arrive at a diagnosis, assess treatment response, or is it preventive screening?
  • Are there alternative imaging procedures that could accomplish the same goal without medical radiation, such as ultrasound or magnetic resonance imaging?
  • What are the risks of not having the imaging procedure done?
  • How old is the patient? The risks for pediatric and adolescent patients may be different than for adults.
  • Is the patient pregnant, possibly pregnant, or breastfeeding?
  • What other procedures is the patient likely to undergo during this workup?
  • What is this person’s radiation exposure from previous medical procedures? For example, has the person undergone multiple CT or nuclear medicine scans in the past?
  • What is this person’s occupational exposure to radiation, if any?
  • Will the imaging exam be performed on low-dose equipment?

The standard unit of measure for radiation absorbed by an individual is called the “Sievert,” or Sv (sometimes identified by a smaller unit called the “millisievert,” or mSv). Common medical imaging tests such as X-rays or mammograms generally expose patients to a radiation dose of less than 1 mSv.

Other procedures using CT, nuclear stress tests, or fluoroscopy-guided exams often involve radiation in the range of 5-40 mSv.

single exposure at these diagnostic levels may not pose much risk to the patient. But when a patient has numerous tests over a period of time, the cumulative exposure may raise the level of risk. To minimize cumulative exposure, physicians should determine whether a procedure using medical radiation is necessary to achieve the diagnosis or whether an alternative imaging procedure may offer the same diagnostic benefit.

Read more:

12.   How Safe or Unsafe Are Medical Imaging Procedures?

Radiation exposure is a known risk factor for cancer. Recent estimates suggest, for example, that as many as two percent of cancers could be attributed to radiation during CT scans. Although the radiation exposure from a single test is minimal, the frequency of the use of imaging tests that emit radiation continues to grow expansively, and often patients undergo repeated or multiple types of tests, thereby increasing their cumulative exposure to potentially cancer-causing radiation.

Read more:

Advice to Patients

Lately, we have noticed that certain medical centres have been urging   cancer patients to perform regular CT or PET scans (some every 3 months)  to “monitor” the progress of their cancer treatment. Sometimes some cancer patients think that such CT/PET scans are “treatment” itself. The medical establishment obviously have a financial benefit in urging you to perform more imaging/diagnostic procedures.

When deciding whether or not to perform further imaging/diagnostic procedures, we would advise you to seek answers to the following:

  • What is the purpose of the procedure? For example, is it to arrive at a diagnosis, assess treatment response, or is it preventive screening?
  • Are there alternative imaging procedures that could accomplish the same goal without medical radiation, such as ultrasound or magnetic resonance imaging?
  • What are the risks of not having the imaging procedure done?
  • What is your radiation exposure from previous medical procedures? For example, have you undergone multiple CT or nuclear medicine scans in the past?

Each time you are asked to do a CT Scan/PET Scan, be aware of the amount of radiation that would be bombarding your body and do remember that the radiation is accumulative i.e. it accumulates in your body, not the doctor’s body (except his wallet gets heavier). The following article is self explanatory:


When the Results of PET and CT Scans Do Not Tell the Same Story

About a year ago, a lady from a neighbouring country urgently flew to see me. She came to discuss the CT scan results of a VIP (very important personality).  The CT scan clearly stated that this VIP had tumours in his lungs and liver. His doctor suggested immediate surgery. This lady wanted my advice.

Just to be on the safe side, I suggested that it might be a good idea to know the extent of possible metastases – if at all there is any spread – before undergoing surgery. Towards this end, I suggested that he goes for a PET scan. At that time, my impression was that the PET is the state-of-the-art imaging procedure. It is more accurate and reliable than the CT scan.

After a few days, I was informed by phone that the PET done did not show any malignancy – no cancer!  Nevertheless, I hesitated to believe the result. At that time, I “interpreted” the message differently. I had the impression that this VIP wanted to avoid any dealing with me and therefore the only polite “save face” strategy was to tell me that there was no cancer. So he does not need my help anymore!

Some months later, I got to know through another person that this VIP had undergone a liver surgery. This planted the first seed of doubt in my mind about the reliability of PET scan.

Patient from Kelantan

In October 2011, I received a fax from a patient in Kelantan.  This 47-year-old male patient did a CT scan on 22 August 2011. The results indicated:

  • Three well-defined heterogenously hypodense small liver lesions in segments 2, 7 and 8. The largest in segment 2 measuring 0.7 x 1.0 cm. Foci of non-enhancing calcification seen in segment 8 with no mass effect, likely to represent old infection.
  • Small, well-defined lung nodule seen in the anterior segment of right upper lobe of 0.3 cm in diameter. A small pleural-based nodule is also seen in the posterior segment of left lower lobe measuring 0.3 cm in diameter.
  • Well-defined small sclerotic bony lesions see in at right acetabulum, left ilium and left neck of femur likely to represent bony island. Multilevel degenerative of the visualized spine.

Impression: Known case of sigmoid colon carcinoma with liver and lung metastases.

This same patient went to do a PET scan in Kuala Lumpur on 5 October 2011. The PET scan result indicated the following:

  • There is normal uptake in all the organs examined, in particular the colon, liver, lungs, lymph nodes, spleen, pancreas, kidneys, adrenal glands, brain and bones. There is no pleural effusion or ascites.

Impression: No malignant lesion is detected.

This was the second alarm bell. However, I did not take this episode to heart because the patient did not come to see me personally and I did not get to see the images of both the scans. As such I do not have any “solid” evidence to back up what I say – although I did have the faxed reports of both the procedures.

Patient from Penang

The third alarm bell – on 5 February 2012. A man came to our Centre with the medical reports of his wife who has ovarian cancer. She underwent surgery – TAHBSO (Total abdominal hysterectomy with bilateral salpingo-oophorectomy) – on 15 September 2010. This time I had the opportunity to examine the images of both the PET and CT scans.

Six months after the surgery, a PET scan was done at a private hospital in Selangor on 19 April 2011. 

Technique: PET scan was performed from the vertex of the skull to the thighs after intravenous administration of 8.5 mCi of F-18 Fluorodeoxyglucise (FDG). Oral gastrograffin, oral bromazepam and intra-venous lasix were given. Fasting blood glucose – 6.9 mmol/l/


  1. Head – There is normal physiological localization of the FDG in the cerebrum and the cerebellum. The uptake and the distribution of the radiotracer in the posterior nasopharyngeal tissue, salivary gland and tonsils are within normal physiological limits.
  2. Neck –The thyroid gland displaces normal FDG upake. There is no FDG avid cervical lymphadenopathy. 
  3. Thorax – Normal FDG uptake is seen in both breasts. There is no FDG avid axillary lymphadenopathy, bilaterally. There is no FDG avid mediastinal lymphadenopathy. Thre is no pleural effusion seen.
  4. Abdomen – There is no suspicious FDG avid lesion see in the liver. U[take and distribution of the radiotracer in the gallbladder, spleen, adrenals, pancreas, kidneys and bowels are within normal physiological limits. There is no FDG avid abdominal lymphadeopathy. Ascites is not present.
  5. Pelvis – TAHBSO noted. There is no definite abnormal FDG lesion seen in the pelvic floor and vaginal stump. There are some superficial subcentimetre size non-FDG avid inguinal nodes which are likely to be reactive nodes. There is no FGD pelvic lymphadenopathy.
  6. Musculoskeletal – There is symmetrical FDG avid activity seen in the acromioclavicular joints bilaterally, probably due to imflammation. There is no suspicious FDG avid lesion seen in the visualized skeleton.


  1. There is no evidence of residual hypermetabolic disease in the vaginal stump and pelvic floor.
  2. There is no evidence of hypermetabolic loco-regional or distant metastatic disease at present.
  3. Although there is no evidence of macroscopic disease at present, the presence of microscopic disease cannot be excluded.

The above report was signed by the Consultant Nuclear Medicine Physician.

Three months later, 25 July 2011, this same lady did an ultrasound of her abdomen and pelvis at the same private hospital in Selangor. The results indicated:

  • Mild ascites is seen.
  • A thick layer of lobulated parietal pleural masses are seen subdiaphragmatically, around the liver edges superiorly and laterally.
  • It measures up to 6 x 3.5 cm around segment 8 of the liver and 4.5 x3.7 cm superior to segment 2.
  • Intrahepatically, a hypoechoic nodule measuring 15 mm is noted in segment 3.
  • There are also intraperitoneal mesenteric deposit, measuring up to 3.6 x 2.8 cm in the right lumbar territory.
  • The uterus and ovary absent.

Impression: Extensive intraperitoneal metastases with ascites. Significant progression of the metastasis is seen.

On 16 November 2011, a CT scan of this same lady was done at a private hospital in Penang. The results indicated:

  • Extensive lobulated hypodense mass noted in the peritoneum and mesentery of upper abdomen.
  • The mass measured approximately 25 to 65 mm in diameter each.
  • The mass creep in between the diaphragm and the dome of the liver with marked subcapsular compression of liver.
  • Masses also noted in the lesser sac and the para-splenic space.
  • Moderate ascites.
  • Previous hysterectomy.

Impression: In view of the clinical history, features are consistent with relapsed of carcinoma of ovary with extensive peritoneal and omental metastasis.

Let me end with another story. There was this man who had stomach cancer. After surgery he came to seek our help and was started on the herbs. According to him, he felt good. He liked gardening and used to bring a lot of hot “cabai burung” whenever he came to our centre. He knew that I like hot chilly. One day this patient came and told us that he just had just done a scan and his doctor told him he had no more cancer – everything was clean. So he did not want to take any more herbs – after all the doctor said he was already cured! Although I did warn him that there is no such thing as a cure! No, his doctor’s words were more powerful and after all this was what every cancer patient wants to hear anyway.

A few months later, someone showed me his obituary in the newspaper. Besides learning that he was dead, I also learned that this man was a Datuk – a titled, respected personality in the community.

From the above stories, I learned that we can cause grave danger to patients by telling them things that they only want to hear. Or sending them for test that can give results that they are looking for –  of course, the more high-tech the equipment involved, the more convincing it would be.  So danger is not only confined to giving them the “wrong kind” of medication – the more toxic the more dangerous.

In this case the lady patient above had a choice – to believe that she had NO cancer after her surgery. What a great relief and welcoming news when the high tech state-of-the art technology similarly confirmed this belief. The lady also had another choice – to believe that surgery did not in any way cure her cancer and actually there were a lot more of the cancer cells left behind after the surgery! High tech gadget was unable to detect that but intuition and plain old-fashion experience is able to decipher that possibility.

Incidentally, while writing this article, I was also reading this humorous, oft-quoted all-time favorite book written by Dr. Oscar London, M.D., the pseudonym of an internist practising in Berkeley, California.