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HUMAN INVESTIGATIONS INVOLVING RADIATION EXPOSURE:

 

Research involving exposure of humans to ionizing radiation requires additional specific approval from the University Radiation Safety Committee (HIRE subcommittee) or Radioactive Drug Research Committee (RDRC). The following guidance is provided to help you determine which committee approval is required for your study.


Examples of this type of use are: a research project intended to obtain basic information regarding the metabolism (including kinetics, distribution, and localization ) of a radioactively labeled drug or regarding human physiology, pathophysiology or biochemistry , but not intended for immediate therapeutic, diagnostic or similar purposes or to determine the safety and effectiveness of the drug in humans for such purposes (i.e. to carry out a clinical trial) Certain basic research studies, e.g. studies to determine whether a drug localizes in a particular organ or fluid space and to describe the kinetics of that localization , may have eventual therapeutic or diagnostic implications, but the initial studies are considered to be basic research.
Note: This committee is appointed by the Medical Center and its members must be approved by the FDA.

Uses of Ionizing Radiation That Do Not Need to Be Reviewed By the Radiation Safety Committee (HIRE subcommittee)

The following consent language may be used for protocols that involve a single X- ray procedure and involve exposure to ionizing radiation that results in a total effective dose to the study participant that is less than or equal to 300 mrem (millirem)*.


Abdominal X-Ray (1 film)
"This study involves radiation exposure from an abdominal x-ray.  As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself.  The radiation dose you will receive in this study is about the amount that you receive over 150 days from background radiation.  The risk from this dose is small.  This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Barium Swallow (24 images)
"This study involves radiation exposure from stomach x-rays.  As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself.  The radiation dose you will receive in this study is about the amount that you receive over 240 days from background radiation.  The risk from this dose is small.  This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Chest X-Ray (PA)
"This study involves radiation exposure from a chest x-ray. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 5 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Chest X-Ray (PA + lat)
"This study involves radiation exposure from a chest x-rays. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 29 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

DEXA (Bone Mineral Densities)
"This study involves radiation exposure from a DEXA (insert type of scan as shown below).  As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself.  The radiation dose you will receive in this study is about the amount that you receive over (use list below) days from background radiation.  The risk from this dose is small.  This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired." 

Fontaine Imaging Center Hologic QDR Series Machines
For any one of the following scans: PA Lumbar Spine, Lateral Lumbar Spine, Hip, Whole Body or Forearm – use "less than 1 day"

For a pQCT -  use "less than 1 day"

Note:  If the machine or type of scan is not listed above, please contact Radiation Safety (2-4917) for further information.

Extremity (Hand/Foot) X-Ray
"This study involves radiation exposure from an extremity (hand, foot, etc.) x-ray. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 1 day from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Head CT Scan
"This study involves radiation exposure from a CT scan (X-ray) of your head. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 240 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Hip X-Ray
"This study involves radiation exposure from an X-ray of your hip. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 100 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Knee X-Ray
"This study involves radiation exposure from an X-ray of your knee. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 101 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Mammograhy (Standard 4 Views)
"This study involves radiation exposure from an X-ray of your breasts. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 85 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Sinus Radiographs (3 View Plane Films)
"This study involves radiation exposure from three X-rays of your sinus. As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over 70 days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Note: If a single film is required, then the radiation dose and calculated percentage of the yearly background dose may be reduced by a third and the consent risk statement adjusted accordingly.

*mrem – unit of measurement of dose (how much energy is absorbed by the body from radiation)

Guidance for IRB (HIC) Protocols Involving the Use of Ionizing Radiation

The Radiation Safety Committee (RSC) is charged by Federal and State regulatory agencies to oversee the use of ionizing radiation at the University of Virginia. Sources of ionizing radiation include both radioactive materials and radiation-producing devices. Examples of uses of these sources include (but are not limited to) chest x-rays, DEXA scans, CT scans, fluoroscopy, and nuclear medicine procedures.

If uses of radiation or radioactive materials do not meet the criteria for "medically indicated," they are regarded as "indicated for research" and the RSC must review the protocol. Use of ionizing radiation in human research in any manner that does not directly benefit the patient/subject (i.e. beyond standard of care) must be approved by the RSC, specifically the Human Investigations Involving Radiation Exposure (HIRE) subcommittee or the Radioactive Drug Research Committee (RDRC).

To comply with FDA and DHHS guidelines and regulations, the University IRB must assure that the patient/subject enrolled in an investigational study is adequately informed about risk. Since the use of ionizing radiation in humans is associated with health risks in proportion to the amount of radiation received, it is the responsibility of the Principal Investigator (PI) to inform the IRB of any ionizing radiation procedures employed in the study. Additionally, the PI will be required to identify those ionizing radiation procedures that are beyond routine standard of care and for research purposes only (i.e. procedures that do not directly benefit the patient/subject).

Beneficence obligates the researcher to secure the well-being of all study participants. It is your responsibility to protect participants from harm, as well as ensure that they experience the possible benefits of involvement. Balancing risk and benefits is an important consideration. The key, according to the 1979 Belmont Report on the protection of human subjects, is to "maximize possible benefits and minimize possible harms." When do the benefits to society outweigh the possible risks of research? This is an ethical question that researchers face. The peer review process via this worksheet, and the principle of beneficence help you answer this question and protect your research participant’s rights. The responsibility to protect and inform research participants is ultimately yours and cannot be ignored or delegated. Although you may delegate various tasks to certain team members, you cannot delegate the responsibility of protecting and informing participants of their rights. Submittal of your protocol and consent form to the RSC is a peer review process designed to assist you in providing the appropriate consent language for the radiation dose that will be received by the participants in your study.

Consent Language
Once the total radiation dose to the subject has been calculated, the appropriate consent language will be chosen from the templates shown below. You may cut and paste the consent language into your consent form.

The protocol and consent form must then be provided to the RSC/HIRE for review and approval. Please send these documents along with the Radiation Dose Worksheet to dps3c@Virginia.edu.

Dose Limits
Please be aware of the following dose limits for use of radiopharmaceuticals that are approved by the RDRC subcommittee of the RSC.
Title 21 – FDA Part 361 (b)(3)(i), Limit on radiation dose
The amount of radioactive material to be administered shall be such that the subject receives the smallest radiation dose with which it is practical to perform the study without jeopardizing the benefits to be obtained from the study. Under no circumstances may the radiation dose to an adult research subject from a single study, or cumulatively from a number of studies conducted within 1 year be generally recognized as safe if such dose exceeds the following:
3 rem per single administration or study to the whole body, blood-forming organs, lens of the eye, and gonads; and 5 rem annually.
For other organs, the limits are 5 rem per single administration or study, and 15 rem annually. Fro minors (under the age of 18), limits are 1/10th the adult values.

Template Consent Language for Radiation Risks

After completing the Radiation Dose Worksheet, select the appropriate Template consent language (based on your calculated total Dose Equivalent) to insert into your consent form under Radiation Risks.

Note: Average annual background dose in Charlottesville assumed to be 300 mrem/yr or 0.82 mrem/day)

Template A (Total Effective Dose less than or equal to 300 mrem)

"This study involves radiation exposure from (insert type of procedure or procedures involving radiation exposure). As part of everyday living, everyone is exposed to a small amount of background radiation that comes from soil, rocks, outer space and within the body itself. The radiation dose you will receive in this study is about the amount that you receive over (insert number of days) days from background radiation. The risk from this dose is small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."

Template B (300 mrem < Total effective dose = or < 5 rem)

"This study involves radiation exposure from (insert maximum number) injections (scans or repetition) of (insert quantity of radioactive material, in units of millicuries; or type of x-ray procedure).
[Using the standard way of describing radiation dose, from participating in this study, you will receive a total of XX rem to your (insert highest-dosed organ), XX rem to your (insert 2nd highest-dosed organ), and XX rem to your (insert 3rd highest-dosed organ). All other organs will receive smaller amounts of radiation.]
[Although each organ will receive a different dose,] the total effective radiation dose you will receive from these procedures is approximately XX rem. For comparison this dose is (XX times or XX% of) the annual radiation dose safely allowed for a radiation worker such as the person performing your (type of procedure). The precise risk from this dose is not known but is thought to be small. This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired."
If you are pregnant [or breastfeeding], you may not participate in this research study. It is best to avoid radiation exposure to unborn [or nursing] children since they are more sensitive to radiation than adults."

You should consider providing the patient with the radiation information handout provided at the following link:

Template C (Total effective dose > 5 rem)

"This study involves radiation exposure from (insert maximum number) injections (scans or repetition) of (insert quantity of radioactive material, in units of millicuries; or type of x-ray procedure).
[Using the standard way of describing radiation dose, from participating in this study, you will receive a total of XXrem to your (insert highest-dosed organ), XX rem to your (insert 2nd highest-dosed organ), and XX rem to your (insert 3rd highest-dosed organ). All other organs will receive smaller amounts of radiation.
[Although each organ will receive a different dose,] the total effective radiation dose you will receive from these procedures is approximately XX rem. For comparison this dose is (XX times or XX% of) the annual radiation dose safely allowed for a radiation worker such as the person performing your (type of procedure).
This dose is (XX times) the annual radiation dose safely allowed for a radiation worker such as the person performing your (type of procedure). One possible effect that could occur at these doses is a slight increase in the risk of cancer. The excess cancer risk from such a dose is estimated to be (calculate using the risk coefficient for fatal cancer in the general population of 4 in 10,000 per rem)

(If appropriate, include discussion about possible acute and chronic organ effects of radiation therapy, specific to study and subjects population).
The benefit(s) from your participation in this study are (describe). The benefits from the study should be weighed against the possible detrimental effects of radiation, including an increased risk of cancer. In this particular study the risk is considered (acceptable, moderate). This radiation exposure is not necessary for your medical care but is necessary to obtain the research information desired.

If you are pregnant or breastfeeding, you may not participate in this research study. It is best to avoid radiation exposure to unborn or nursing children since they are more sensitive to radiation than adults."

You should consider providing the patient with the document "Information on Radiation Exposure for University Virginia Research Subjects and the Research Team" provided at the following link:

Information on Radiation Exposure for
University Virginia Research Subjects and the Research Team

Myth and Reality
Excerpt from the National Cancer Institute
http://www.cancer.gov/clinicaltrials/conducting/informed-consent-guide/page2

Myth: Informed consent is designed primarily to protect the legal interests of the research team.

Reality: The purpose of the process is to protect you and other participants by providing access to information that can help you make an informed choice. It also is designed to make you aware of your rights as a participant

Myth: Medical personnel are busy, so I can't really expect them to keep me informed as the trial progresses or listen to my questions.

Reality: The research team has a duty to keep you informed, make sure that you understand the information they provide, and answer your questions. If you ever feel that you are not getting what you need, do not hesitate to speak up. You will be given the name and phone number of a key contact person who can answer your questions throughout the course of the trial. Keep in mind that people like you are making this research possible through their willingness to participate.

Both the participant and the research team have a responsibility to be informed regarding the risks associated with the radiation exposure involved in this study. The following information is provided to increase your understanding of radiation exposure and the risks associated with the exposure.

Helpful websites:

Information for doctors
http://www.icrp.org/docs/Rad_for_GP_for_web.pdf

The average person in the United States receives a radiation dose of about 0.3 rem (or 300 mrem) per year from natural background sources, such as from the sun, outer space, and from radioactive materials that are found naturally in the earth’s air and soil.
The effects of radiation exposure on humans have been studied for over 60 years. In fact, these studies are the most extensive ever done of any potentially harmful agent that could affect humans. In all these studies, no harmful effect to humans has been observed from the levels of radiation less than 5 – 10 rem. However, scientists still disagree on whether radiation doses at these levels are harmful.

One possible effect that could occur at these doses is a slight increase in the risk of cancer. Please be aware that the natural chance of a person getting a fatal cancer during his/her lifetime is about 1 out of 4 (or 25 percent).

One concern some people may have about radiation exposure is the effect on fertility or on the possibility of causing harm to future children (i.e., genetic risk). Doses of 5 – 10 rem are well below the levels that affect fertility. In addition, genetic effects have not been seen in humans who have been exposed to radiation. The information on genetic effects currently available is based on animal experiments using doses of radiation much higher than the amount you will receive in this study.

It is best to avoid radiation exposure to unborn or nursing children since they are more sensitive to radiation than adults.

There continues to be absence of scientific certainty regarding the relationship between low doses and health effects. Consequently, the scientific community generally makes the conservative assumption that any exposure to ionizing radiation can cause biological effects that may be harmful to the exposed person and that the magnitude or probability of these effects is directly proportional to the dose. These effects may be classified into three categories.

Somatic Effects: Physical effects occurring in the exposed person. These effects may be observable after a large or acute dose (e. g., 100 rem (1 Sv) or more to the whole body in a few hours); or they may be effects such as cancer that may occur years after exposure to radiation.

Genetic Effects: Abnormalities that may occur in the future children of exposed individuals and in subsequent generations (genetic effects exceeding normal incidence have not been observed in any of the studies of human populations).

Teratogenic Effects: Effects such as cancer or congenital malformation that may be observed in children who were exposed during the fetal and embryonic stages of development (these effects have been observed from high, i.e., above 20 rem (0.2 Sv), acute exposures).

The normal incidence of effects from natural and manmade causes is significant. For example, approximately 20% of people die from various forms of cancer whether or not they ever receive occupational exposure to radiation.

When radioactive materials enter the body, they go to various organs or are excreted from the body, depending on the biochemistry of the material. Most materials used in medicine are excreted from the body in a few days.

When x-rays, gamma rays, and ionizing particles interact with living materials such as our bodies, they may deposit enough energy to cause biological damage. Radiation can cause several different types of events such as the very small physical displacement of molecules, changing a molecule to a different form, or ionization, which is the removal of electrons from atoms and molecules. When the quantity of radiation energy deposited in living tissue is high enough, biological damage can occur as a result of chemical bonds being broken and cells being damaged or killed. These effects can result in observable clinical symptoms.

The human body has a remarkable ability to repair damaged cells in the body. Events that occur in a cell, when damaged by radiation, can result in:

The body can usually repair or destroy the mutated cell with no permanent damage, or the mutated cell can become precancerous, which could go on to become cancerous. Ionizing radiation is only one of many agents with the potential for causing cancer. There are several everyday products we buy and use that have potentially cancer causing chemical agents in them. It is important to note that mutations in cells do not always cause cancer. Some cell changes are benign or the cell may die. These changes do not lead to cancer.

Health effects from exposure to radiation range from no effect at all, to death, including diseases such as leukemia or bone, breast, and lung cancer. Very high (100s of rads), short-term doses of radiation have been known to cause prompt (or early) effects, such as vomiting and diarrhea, skin burns, cataracts and even death.

What is the difference between acute and chronic radiation dose?

Acute radiation dose usually refers to a large dose of radiation received in a short period of time. Chronic dose refers to the sum of small doses received repeatedly over long time periods, for example, 20 mrem (or millirem, which is 1-thousandth of a rem) (0.2 mSv) per week every week for several years. For example, a dose to the whole body of about 300-500 rads (3-5 Gy), more than 60 times the annual occupational dose limit, if received within a short time period (e.g., a few hours) will cause vomiting and diarrhea within a few hours; loss of hair, fever, and weight loss within a few weeks; and about a 50 percent chance of death if medical treatment is not provided. These effects would not occur if the same dose were accumulated gradually over many weeks or months. Thus, one of the justifications for establishing annual dose limits is to ensure that occupational dose is spread out in time.

It is assumed for radiation protection purposes that any radiation dose, either acute or chronic, may cause delayed effects. However, only large acute doses cause early effects; chronic doses within the occupational dose limits do not cause early effects. A radiation dose may be caused by exposure to radiation that originates outside the body, called "external exposure," or by exposure to radiation from radioactive material that has been taken into the body, called "internal exposure".

It is the current scientific consensus that a rem of radiation dose has the same biological risk regardless of whether it is from an external or an internal source. The sum of external and internal dose is called the total effective dose equivalent (TEDE) and is expressed in units of rem.

We don’t know exactly what the chances are of getting cancer from a low-level radiation dose, primarily because the few effects that may occur cannot be distinguished from normally occurring cancers. However, we can make estimates based on extrapolation from extensive knowledge from scientific research on high dose effects. The estimates of radiation effects at high doses are better known than are those of most chemical carcinogens.

From currently available data, the NRC has adopted a risk value for an occupational dose of 1 rem (0.01 Sv) Total Effective Dose Equivalent (TEDE) of 4 in 10,000 of developing a fatal cancer, or approximately 1 chance in 2,500 of fatal cancer per rem of TEDE received. The uncertainty associated with this risk estimate does not rule out the possibility of higher risk, or the possibility that the risk may even be zero at low doses and dose rates, It is important to understand the probability factors here. A similar question would be, "If you select one card from a full deck of cards, will you get the ace of spades?" This question cannot be answered with a simple yes or no. The best answer is that your chance is 1 in 52. However, if 1000 people each select one card from full decks, we can predict that about 20 of them will get an ace of spades, Each person will have 1 chance in 52 of drawing the ace of spades, but there is no way we can predict which persons will get that card. The issue is further complicated by the fact that in a drawing by 1000 people, we might get only 15 successes, and in another, perhaps 25 correct cards in 1000 draws. We can say that if you receive a radiation dose, you will have increased your chances of eventually developing cancer. It is assumed that the more radiation exposure you get, the more you increase your cancer? Probably not. Based on the risk estimates previously discussed, the risk of cancer from doses below the occupational limits is believed to be small.

Assessment of the cancer risks that may be associated with low doses of radiation are projected from data available at doses larger than 10 rem (0.1 Sv). We have data on cancer probabilities only for high doses. Only in studies involving radiation doses above occupational limits are there dependable determinations of the risk of cancer.

For regulatory purposes, the NRC uses a dose response curve which shows the number of effects decreasing linearly as the dose decreases. Because the scientific evidence does not conclusively demonstrate whether there is or is not an effect at low doses, the NRC assumes for radiation protection purposes, that even small doses have some chance of causing cancer. Thus, a principle of radiation protection is to do more than merely meet the allowed regulatory limits; doses should be kept as low as is reasonably achievable (ALARA). This is as true for natural carcinogens such as sunlight and natural radiation as it is for those that are manmade, such as cigarette smoke, smog, and x-rays.

To help put the risks of radiation in perspective with other every day risks, the following table is provided:
Estimated Loss of Life Expectancy from Health Risks

Estimated Loss of Life Expectancy from Health Risks
Health Risk Estimate of Life Expectancy Lost(average)
Smoking (20 cigarettes a day) 6 years
Overweight (by 15 %) 2 years
Alcohol consumption (U.S.A.) 1 year
All accidents combined 1 year

Motor vehicle

207 days

Home accidents

74 days

Drowning

24 days
All natural hazards (earthquake, lightning, etc.) 7 days
Medical radiation 6 days
Occupational Exposure ----

0.3 rem/yr from age 18 to 65

15 days

1 rem/yr from age 18 to 65

51 days

These estimates are considered by the Regulatory community to be the best available for the worker to use to make an informed decision concerning the acceptance of the risks associated with exposure to radiation. Compared to many other occupations and their associated occupational hazards such as construction work or law enforcement, the hospital radiation workers’ risk to occupational radiation exposure is considered to be relatively small.

Each of us receives approximately 360 millirem a year in background radiation exposure. The amount can be higher or lower than this and varies based on your geographical location. Radon gas is thought to be the largest contributor to one's exposure to background radiation; however some controversy exists among scientists on how much that contribution is. Initial estimates claim the average radon exposure to an individual to be about 200 millirem a year. The following chart illustrates each category's contribution to the sum total background radiation we receive each year.

pie graph
NCRP Report 93, Ionizing Radiation Exposure to the Population of the United States, 1987


Maintained by: Environmental Health & Safety
Last Modified: Monday, March 12, 2007 14:56
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