Trigger 3, Radio Biology: Basic Radiation Concepts

Sir Jeff's Hand-Outs, Trigger 3

Radiation

Radiation

the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization

Ionizing radiation

has enough energy to remove tightly bound electrons from atoms, which can cause ionization of the atom.

• X-rays, gamma rays

Non-ionizing radiation

has less energy and does not have the ability to ionize atoms.

• radio waves, microwaves, and infrared radiation.

• vacuum

• medium

complete the context:

Radiation can travel through a BLANK and does not require a BLANK to propagate.

• the type of radiation

• the properties of the material.

Radiation can penetrate various materials to varying degrees, depending on WHAT?

beneficial and harmful

complete the context:

Radiation can be both BLANK to living organisms, depending on the type, amount, and duration

inverse square law

the intensity of radiation decreases with distance from the source, following WHAT LAW?

particulate radiation

composed of subatomic particles that are emitted from the nucleus of an atom during radioactive decay.

• alpha particles

• beta particles

• neutrons

examples of particulate radiation:

alpha particles

example of particulate radiation

• are positively charged and consist of two protons and two neutrons

beta particles

example of particulate radiation

• are high-speed electrons that are emitted from the nucleus during radioactive decay.

neutrons

example of particulate radiation

• are neutral particles that are emitted from the nucleus during nuclear reactions

electromagnetic radiation

a type of energy that travels through space in the form of electromagnetic waves

• gamma rays

• x-rays

• ultraviolet (UV) radiation

• visible light

• radio waves

examples of electromagnetic radiation:

gamma rays

example of electromagnetic radiation

• are high-energy electromagnetic radiation that is produced during nuclear reactions and the decay of radioactive elements

x-rays

example of electromagnetic radiation

• are a form of electromagnetic radiation that is used in medicine to image the interior of the body.

ultraviolet (UV) radiation

example of electromagnetic radiation

• are a form of electromagnetic radiation that is present in sunlight.

visible light

example of electromagnetic radiation

• are a form of electromagnetic radiation that can be seen by the human eye.

radio waves

example of electromagnetic radiation

• are a form of electromagnetic radiation that is used for communication and navigation, including television and radio broadcasting, cell phone communication, and GPS.

300 mrem or 3mSv

what is the anual dose of natural environmental radiation?

radon

what is the largest source of natural environmental radiation?

1. natural environmental radiation

2. man-made radiation

what are the sources to human exposure to radiation?

• cosmic rays

• terrestrial radiation

• internally deposited nuclides

the components of natural environmental radiation are:

cosmic rays

component of natural environmental radiation

• are high-energy particles, that originate from outer space.

• they travel through space at extremely high speeds, often approaching the speed of light.

terrestrial radiation

component of natural environmental radiation

• refers to the naturally occurring radiation that originates from radioactive elements present in the Earth's crust and environment such as uranium, thorium, and radon.

internally deposited nuclides

component of natural environmental radiation

• are radioactive materials that have entered the human body through ingestion, inhalation, or absorption.

320 mrem or 3.2 mSv

what is the annual dose for man-made radiation?

diagnostic x-ray

what is the largest source for man-made radiation?

• natural background radiation

• medical radiation exposure

• occupational exposure

• environmental exposure

• intentional exposure

• consumer products

• public exposure

classification of human exposure to radiation:

external exposure

classification of human exposure to radiation: natural background radiation

• this refers to radiation exposure that comes from sources outside the human body

• It includes exposure to cosmic rays from space, terrestrial radiation from radioactive elements in the Earth's crust, and radiation from building materials.

internal exposure

classification of human exposure to radiation: natural background radiation

• this involves the ingestion or inhalation of naturally occurring radioactive substances [radon gas or radioactive isotopes of elements (uranium, thorium)]

  • these substances can accumulate in the body and emit radiation from within.

diagnostic examinations

classification of human exposure to radiation: medical radiation exposure

• medical procedures [x-rays, computed tomography (CT) scans, fluoroscopy] involve exposing the body to ionizing radiation for diagnostic purposes.

  • the level of exposure varies depending on the type of procedure and the body part being examined.

radiation theraphy

classification of human exposure to radiation: medical radiation exposure

• radiation is sometimes used in controlled doses to treat certain medical conditions, particularly cancer.

• this involves delivering targeted radiation to specific areas of the body to destroy cancer cells.

workers in radiation-related industries

classification of human exposure to radiation: occupational exposure

• individuals working in fields like nuclear power plants, radiology, and industrial settings where radiation sources are used can be exposed to radiation as part of their job.

• occupational exposure is regulated and monitored to ensure safety.

accidental releases

classification of human exposure to radiation: environmental exposure

• radiation incidents or accidents, such as nuclear accidents like Chernobyl or Fukushima, can lead to widespread exposure of populations to elevated levels of radiation.

radon exposure

classification of human exposure to radiation: environmental exposure

• radon gas can accumulate in buildings, especially in areas with high levels of naturally occurring radon.

• prolonged exposure to radon can increase the risk of lung cancer.

lung cancer

prolonged exposure to radon can increase the risk of, WHAT?

radiation research

classification of human exposure to radiation: intentional exposure

• In scientific research, controlled exposure to radiation might be necessary to study its effects on living organisms.

• this exposure is closely monitored and regulated to ensure safety and ethical considerations.

space travel

classification of human exposure to radiation: intentional exposure

• astronauts traveling in space are exposed to higher levels of cosmic radiation due to the lack of Earth's protective atmosphere.

• this is a concern for long-duration space missions.

radiation-emitting devices

classification of human exposure to radiation: consumer products

• some consumer products, like smoke detectors, certain types of watches, and airport security scanners, contain radioactive materials or emit radiation.

  • however, the radiation levels are usually very low and pose minimal risk.

general public

classification of human exposure to radiation: public exposure

• the general population can be exposed to low levels of radiation from various sources, including consumer products, food, water, and the environment.

  • Regulatory limits are in place to ensure public safety

• air kerma (Gy_a)

• rad (Gy_t)

• sievert (Sv)

• becquerel (Bq)

radiation quantities and units:

air kerma (Gy_a)

radiation quantities and units

• kinetic energy transferred from photons to electrons during ionization and excitation

• A unit of radiation exposure or intensity

• Measured in joule per kilogram (J/kg) where 1 J/kg is 1 (Gy_a)

• 1 R = 2.08 x 108 ip/cm3 of air

• 1 R = 2.58 x 10-4 C/kg (Electric charges per unit mass of air or the electrons liberated by ionization)

joule per kilogram (J/kg)

air kerma (Gy_a) is measured in, WHAT?

rad (Gy_t)

radiation quantities and units

• radiation energy absorbed per unit mass and has units of J/kg or Gy_t

• Is used when describing the quantity of radiation received by the patient

• Is a unit of radiation absorbed dose (rad)

• Is related to biologic effects

100 rad

1 Gy_t is equivalent to, what?

sievert (Sv)

radiation quantities and units

• Unit of occupational radiation exposure and effective dose

• Used to analyze radiation monitoring devices

• Customary unit is rem (radiation equivalent man)

100 rem

1 Sv is equivalent to, what?

becquerel (Bq)

radiation quantities and units

• unit of quantity of radioactive material

• unit of radioactivity

• quantity of radioactivity in which a nucleus disintegration per second (1 dps = 1 Bq)

3.7 × 10¹⁰ Bq

1 Ci is equivalent to, what?

radiation absorbed dose (rad)

old/customary radiologic unit for absorbed dose

radiation equivalent man (rem)

old/customary radiologic unit for effective dose

curie (Ci)

old/customary radiologic unit for radioactivity

roentgen (R)

old/customary radiologic unit for exposure

(Gy_t) gray

new/standard radiologic unit for absorbed dose

(Sv) sievert

new/standard radiologic unit for effective dose

(Bq) bequerel

new/standard radiologic unit for radioactivity

(Gy_a) gray

new/standard radiologic unit for exposure

• diagnostic radiology

• dental radiology

• cardiovascular-interventional radiology

• nuclear medicine

• radiation oncology

sources of medical radiation:

• x-ray machines

• nuclear medicine

• positron emission tomgraphy (PET) scanners

sources of medical radiation: diagnostic sources

x-ray machines

sources of medical radiation: diagnostic sources

• widely used for diagnostic imaging to visualize bones, organs, and tissues

• radiography, flouroscopy, mammography

nuclear medicine

sources of medical radiation: diagnostic sources

• patients are administered with a small amount of radioactive material (radiopharmaceutical), which emits gamma rays.

• special cameras detect these gamma rays to create images of internal structures and functions of organs.

positron emission tomography scanners

sources of medical radiation: diagnostic sources

• use positron-emitting radiopharmaceuticals to visualize metabolic processes in the body, helping in cancer detection and monitoring treatment response.

radiation theraphy machines

sources of medical radiation: therapeutic sources

• these machines deliver controlled doses of radiation to target and treat cancerous tissues

• linear accelerators, brachytherapy devices, and proton therapy machines.

radioactive iodine (I-131) theraphy

sources of medical radiation: therapeutic sources

• is used to treat certain thyroid disorders and thyroid cancer.

• is taken up by the thyroid gland and destroys thyroid tissue.

radiopharmaceuticals for theraphy

sources of medical radiation: therapeutic sources

• these deliver radiation to specific tissues to treat conditions like bone metastases or certain types of cancer.

interventional radiology

sources of medical radiation

• involves using imaging techniques (x-rays or fluoroscopy) to guide minimally invasive procedures

• e.g., angiography (imaging of blood vessels), embolization (blocking blood vessels), and catheter-based treatments.