Unit 1 test- intro and radiation quantities and units

radiation

the transfer of energy from 1 location to another

energetic form of radiation is called

x-ray

when passing through normal matter, x-rays were found to produce (+) and (-) charged particles. altered atoms or molecules making up these charged particles were called

ions

x-rays are classified as

ionizing radiation

fundamental principles of x-ray

• invisible

• varying degrees of penetration in normal tissue depending on energy

• travel in straight lines at speed of light until they interact with atoms

• have wide range of energies within the x-ray beam(heterogenous)

• ionizing radiation

what causes injury in normal biologic tissues

production of ions during ionizing radiation and the ejected electrons

living tissue can be damaged by exposure to ionizing radiation called

biological effects

effective measures to safeguard from unnecessary exposures from ionizing radiation

• patients

• personnel

• general public

training for techs and radiologists on how to safely limit radiant energy

1. safe operation of x-ray equipment

2. follow protocols and procedures

3. set correct techniques for patients and limit exposure

4. use shielding when appropriate

how to minimize exposures

1. proper techniques(technique books, proper measuring of body part)

2. procedural factors examples: immobilizations, proper image receptors. positioning around patient limitations

3. human determinants examples: pathological conditions, body habits, movement, environmental(film)

unnecessary exposure

doesn't benefit person with

1. diagnostic info

2. enhancing quality of study

diagnostic efficacy

provides basis for justification of procedures

• the degree to which the diagnostic study reveals presence and absence of a disease in a patient, while adhering to radiation safety guidelines

justification of radiation exposure

1. weigh benefits vs. risk

2. good voluntary risk for

• screening purposes(mammo)

• injuries

• illnesses

ALARA

as low as reasonably achievable

synonym for ALARA

ORP: optimization for radiation protection

radiation induced cancers are

linear, non-threshold

tech responsibilities

quality patient care and quality images

• standards of practice

• ASRT code of ethics

• technique(use smallest amount of radiation)

• ALARA

• minimal repeats

• proper shielding(females 50%, males 90-95%)

• follow protocols

• be educated

radiologist/physican responsibilities

• consulting

• do not order unnecessary exams

• trained radiologists

employer responsibilities

• implement and maintain radiation safety program

• supply resources

• written policy

• exposure audit

cardinal rules

• time

• distance

• shielding

alliance for radiation safety in pediatric imaging

partnership with overall purpose to reduce dose to pediatrics and raise awareness among non-radiology professionals

image gently campaign

2008

initiated to dissemination of pediatric CT dose reduction

pause and pulse: for lower dose of pulsed fluoro

image wisely

2009

ACR and RSNA formed to address adult radiation protection to address concerns about increases of public exposure to ionizing radiation and then lower amount of radiation being clinically used

BERT

background equivalent radiation time

compares amount of radiation received during a specific procedure to amount of natural background radiation over a certain period of time

EXPLAINS PROCEDURES

EDUCATE AND REDUCE ANXIETY

patient education

• explain procedure

• explain follow up

• patient active participant

• answer questions

radiation dose documentation

dictating dose exposures and/or fluro time into radiology reports

second radiation definition

emission of energy in form of electromagnetic waves or as moving subatomic particles passing through space from 1 location to another

2 types of radiation

1. mechanical vibration- causes sound

2. electromagnetic wave radio- radio, microwaves, visible light, x-rays

electromagnetic spectrum

full range if frequencies and wavelengths of electromagnetic waves

ionizing radiation

x-rays and gamma rays

high energy, high frequency= short wavelength that transfers energy and ejects electron from atom

UV rays greater energy than 10

nonionizing radiation

infrared rays, microwaves, radio waves

lower energy, lower frequency= longer wavelength

Uv rays less than 10

not enough kinetic energy to eject electrons from atoms

natural or background radiation

50%

terrestrial

cosmic

internal

terrestrial

crust of earth

examples: uranium, radium, thorium

radon

highest contributor of natural bakcground radiation

• colorless, odorless, radioactive gas present in air

• higher in cooler months

• 2nd leading cause of lung cancer

• emits alpha radiation

• cause 20,000 cancer deaths in US in a year

• EPA recommendations: have annual levels no greater than 4 pico curies per liter of air

cosmic

interaction with sun(solar) and beyond solar system(galactic)

• great intensity occurs at high altitudes, lower intensity occurs at sea levels

internal

part of human metabolism

radioactive materials that are inhaled, ingested, and exists in small quantities within body

human made radiation

50%

nuclear plant accidents

1. TMI(three mile island unit 2)- 1979

2. Chernobyl

3. fukushima(2011)

chernobyl

1986

• thyroid cancer

• increase in breast cancer

• leukemia

medical radiation types

diagnostic machines

radiopharmaceuticals/radioisotopes

x-ray invention by and when

November 8, 1895

by wilhelm conrad roentgen

first clinical x-ray in US

feb. 1896

by: dr. gilman frost and edwin frost

image: boy’s broken wrist

first radiation induced death in US

1904

who: clarence madison dally

edison invention: fluroscope

radiodermatitis (biological effects seen)

reddening of skin from radiation exposure

• resulted in cancer

aplastic enema (biological effects seen)

a blood disorder

bone marrow failure

leukemia (biological effects seen)

abnormal overproduction of WBC

tissue weighing factors developed based on studies of

atomic bomb survivors

exposure

number of ionizations(radiation) interacting with air

measure tube output

colombs/kilogram

air kerma

KERMA: kinetic energy released in matter, air, material/mass

how energy is transferred from beam, of radiation to air

mGy or mGy/min

ESAK(entrance skin air kerma)

dose index that is obtained from center of x-ray beam using a calibrated electronic dose meter

absorbed dose

absorbed dose in patient tissue

the cause of biological damage in exposed tissue

Gy or mGy

equivalent dose(EqD)

overall risk of exposure to patient form ionzing radiation

traditional/badge reports: rem

1 sv= 1000 mSv

effective dose(EfD)

overall risk of exposure to patient from ionizing radiation

dose area product(DAP)

air kerma dose times exposed area of patient

collective effective dose (ColEfD or S)

calculated by average EfD times the # of persons exposed

person-sievert

200 × 0.25=

average effective dose(Eexp)

average dose to individual in a group exposed to a specific source EXCLUDING those NOT exposed from that source

effective dose per individual in US(EUS)

effective dose per individual in US population whether exposed to source or not

somatic effect

effect seen in the individual who received the exposure

short term examples (somatic)

• erythema

• decrease in blood cells

• CNS failure

• disruption of GI structures and function

long term effects(somatic)

• cancer

• cataracts

• shortening of life span

• embryologic effects during 1st semester

genetic effect

damage to cell’s genetic code/DNA molecule

where genetic effects seen

1. offspring of exposed individual

2. exposure is received pre-conception in sperm or ova

can cause: excessive mutations