ch. 1 short answers

how can humans safely control the use of radiant energy?

by using the knowledge of radiation-induced hazards that has been gained over many years and by employing effective methods to limit or eliminate those hazards.

how can radiologic technologists reduce radiation exposure to patients and to themselves?

by using protective devices whenever possible, by following established procedures, and by selecting x-ray machine settings that significantly reduce radiation exposure to patients and themselves.

as ionizing radiation passes through matter, what is the event that may cause injury in normal biologic tissue?

ionizing radiation produces positively and negatively charged particles (ions) along its path. the production of these ions as well as the electrons ejected in the process, is the event that may caused injury in normal biologic tissue.

what are the three cardinal principles of radiation protection?

time, distance, and shielding

how can imaging personnel apply the three cardinal principles of radiation protection to minimize occupational exposure?

1) shortening the length of time spent in a room where x-radiation is produced

2) standing at the greatest distance possible from an energized x-ray beam

3) interposing a radiation-absorbent shielding material between the radiographer and the source of the radiation

what principle can be used as a method for comparing the amount of radiation use in various health care facilities in a particular region for specific imaging procedures?

ALARA

what is the goal of modern radiation protection programs?

to protect persons from both short-term and long-term effects of radiation

regarding the ALARA program in a hospital setting, what are three responsibilities for the program that are entrusted to the radiation safety officer by the administration?

responsible for execution, enforcement, and maintenance

how is risk weighed against benefit in medical radiography?

must far outweigh any slight chance of inducing a radiogenic malignancy or any genetic defects

list four good practices that apply to radiologic technologists and radiologists.

1) educated in the safe operation of x-ray producing imaging equipment

2) use protective devices whenever possible

3) follow established procedures

4) select technical settings that significantly reduce radiation exposure to patients and to themselves

list six consequences of ionization in human cells.

1) creation of unstable atoms

2) production of free electrons

3) production of low-energy x-ray photons

4) creation of highly reactive free molecules capable of producing substances poisonous to the cell

5) creation of new biologic molecules detrimental to the living cell

6) injury to the cell that may manifest itself as abnormal function of loss of function

if a patient is having a chest x-ray examination and the patient asks the radiographer, “how much radiation will I receive from this x-ray?” how should the radiographer respond?

using an estimation based on the comparison of radiation received from the x-ray to natural background radiation received, for example, over a certain number of days.

on what are reference values for patient dose based?

based on large-scale surveys of actual measurements of x-ray machines in hospitals.

for all medical imaging procedures, what concept or principle should the selection of exposure factors always follow?

ALARA

list three advantages of used the BERT method to compare the amount of radiation received with the natural background radiation received over a given period.

1) does not imply radiation risk, simply a means for comparison

2) emphasizes that radiation is an innate part of our environment

3) provides an answer that is easy for the patient to comprehend

what are the radiation workers’ responsibilities to maintain an effective radiation safety program?

be aware of rules governing the workplace and perform duties consistent with ALARA

what are the two objectives of the Image Wisely campaign?

1) lowering the amount of radiation used in medically necessary imaging studies

2) eliminating unnecessary procedures

what are adverse biologic effects?

damage to living tissue of animals and humans exposed to ionizing radiation

how fast do x-rays travel in a straight line until they interact with atoms?

travel at the speed of light (300 million m/s; 3×10⁸ m/s; 186,000 miles/s) until they interact with atoms

what is the responsibility of the technologist with regard to calculation of radiation dose for a specific patient?

to make sure that the radiologist and/or medical physicist has the information needed to carry out the dose estimate