Basics of back protection and radiation protection

Base of support

Portion of body in contact with the floor.

- Keep broad base for stability

What is the Center of Gravity (CoG)?

Center of body weight, usually the pelvis

How do objects affect the Center of Gravity?

Objects lifted add to the CoG

Why should heavy objects be kept close to the Center of Gravity?

To maintain stability and balance

What is the Line of Gravity?

A vertical line passing through the center of gravity

How does the position of the Line of Gravity affect stability?

The body is most stable when the Line of Gravity bisects the base of support.

What is ALARA?

As Low As Reasonably Achievable

Radiation

The transfer of energy that results from a change in an atom (radioactive decay) or a process caused by the interaction of a particle with an atom.

How does radiation effect the body?

it results in bodily damage primarily due to its ability to ionize tissue in its path.

Radiobiology

The study of the effects of ionizing radiation on biological tissue

Measurements of in air exposure

- roentgen (r) for traditional

- Columbs per kilogram (c/kg) for international.

What is Roentgen (R) used to measure?

(Traditional) Exposure in air for x-ray and gamma radiation

How is Roentgen (R) defined?

-1 R = 2.58 x 10^-4 C/kg

What is Columbs per kilogram (C/kg) used to measure?

(International) Exposure in air for x-rays

What is Air Kerma?

Energy released in matter such as electrons from Compton scatter or photoelectric interactions from x-ray exposure.

How is Air Kerma normally expressed?

By the international unit the Gray (Gy).

What has replaced Roentgen in measuring radiation?

Kerma

What is Kerma derived from?

Joules per kilogram (j/kg)

What is the measurement for Kerma?

The Gray (Gy)

How many grays equal one roentgen?

.01 Gray

What are the traditional units for measuring absorbed doses of radiation?

rad (radiation absorbed dose)

What is the SI unit for measuring absorbed doses of radiation?

Gray (Gy)

1 rad =?

100 erg per gram of irradiated tissue

Gray

The SI equivalent of the rad = .01 gray.

1 Gy of air kerma is equal to?

1 Gy of tissue dose

Can RAD or Gy be used to indicate biologic effect?

No

What tool is used to measure radiation exposure?

dosimeter

What are the four types of Dosimeters?

Pocket Dosimeter, Film Badge, Thermoluminescent Dosimeter (TLD), and Optically Stimulated Luminescence (OSL)

Pocket Dosimeter

measures ionization in air, no permanent record.

Film Badge

Dental film is active component, has 3 windows, amount of film darkening equals exposure.

Thermoluminescent Dosimeter (TLD)

Contains Lithium Fluoride crystals that give off light based on rad. exposure when exposed to heat.

optically stimulated luminescence (OSL)

Aluminum oxide crystals, gives off light based on rad exposure when exposed to laser.

What are the 3 cardinal rules to self protection?

Time, Distance, Shielding

Time

Reduce time spent in radiation

Distance

Maintain maximum distance from the source

- Most important of rules due to Inverse Square law.

Shielding

Stand behind lead barriers or others

- Always collimate to reduce exposure

- Wear lead aprons/gloves/thyroid shield

Does lead apron protect from primary ray?

No

First 2 weeks of pregnancy

Spontaneous abortion

2 - 8 weeks of pregnancy

Skeletal/neurologic anomalies

2nd to 3rd Trimesters

Childhood malignancies

Who decides pregnant rad exams

Radiologist

Effective Dose Equivalent limit for Pregnant Women?

.5 rem (5 mSv) During Pregnancy or .05 rem (.5 mSv) per month.

When do technologists inquire about pregnancies?

from ages 12 - 55. Never assume

What is meant by latent effects in radiation exposure?

Probalistic (Stochastic), Probability of response (not severity) is dependent on radiation dose.

How are latent effects measured in radiation exposure?

It is measured with a linear, non-threshold curve.

Which health outcomes are associated with latent effects in radiation exposure?

Latent effects occur only to cancers and genetic effects.

What is the purpose of the curve used to measure latent effects in occupational exposure?

The curve is used to measure occupational exposure.

What are short term (somatic) effects of radiation?

Predictable (nonstochastic)

When do predictable (nonstochastic) effects of radiation occur?

After a predictable amount of radiation is received

How is the severity of biologic response to radiation dose related?

Dependent on dose

How are short term (somatic) effects of radiation measured?

With a linear, threshold curve

Law of Bergonie and Tribondeau

States that cell sensitivity is based on 4 characteristics: Age, Differentiation, Metabolic rate, and Mitotic period.

What units are used to measure Radioactive decay?

Curie and Becquerel

Curie

the quantity of radioactive material (not effect of it) 1 Curie = 3.7 X 10^10 atom disintegrations per sec.

How is Biologic effect measured?

Biologic Effect is measured by the traditional unit of measurement, REM (Radiation Equivalent Man) or the Sievert (Sv) in SI unit of measurement.

REM

has same biological effect as 1 rad of x radiation.

- Used to describe occupational dose in U.S.

How many Sieverts is in 1 REM?

.01 Sv

Determining Biologic effect

Apply radiation weighing factors (quality factors) to the absorbed dose in rad for Tradition or Gy for SI.

Gy X weighing factor (WF) equals?

Sievert

Sv X WF equals?

Rem

What unit will personnel badges be in?

millisieverts

The final Biologic effect of radiation on cells and tissues depends on?

- Type of radiation and its energy

- Type of tissue irradiated

- The charge of particulate radiation

Tissue Weighing Factors

- Gonads .20

- Stomach, Bone Marrow, Colon, Lung .12

- Breast .05

- Other General organs .05

- Cortical Bone/Skin .01

What does effective dose measure?

Overall risk of exposure to radiation

How is effective dose calculated?

E = D X Wt X Wr

What factors does effective dose consider?

Type of radiation and the weighing factor of the tissue

What is the Effective Dose Limit?

Upper boundary of radiation exposure that results in negligible risk of bodily or genetic injury.

What is the annual dose limit for occupational workers?

5 rem (.05 Sv or 50 mSv)