Final Exam RT 202

What is radiology physics?

The branch of physics that deals with the principles and techniques of radiology.

What are ionizing radiations?

Radiations that carry enough energy to liberate electrons from atoms or molecules, leading to ionization.

Name examples of ionizing radiation.

X-rays, gamma rays, and particle radiation (e.g. alpha and beta particles).

What is the photoelectric effect?

The phenomenon where photons incident on a material cause the ejection of electrons.

Define Compton scattering.

A process where X-ray or gamma-ray photons scatter off electrons, resulting in energy loss and a change in direction.

What is the principle of attenuation?

The reduction in intensity of radiation as it passes through matter.

What does Half-Value Layer (HVL) refer to?

The thickness of a material needed to reduce the intensity of radiation to half its original value.

What is the relationship between wavelength and energy in radiology?

Shorter wavelengths correspond to higher energy photons.

Define equivalent dose.

A dose measure that considers the biological effects of different types of radiation.

What is the unit for measuring equivalent dose?

Sievert (Sv).

What is effective dose?

A dose measure that accounts for the type of tissue exposed as well as the type of radiation.

What is the linear energy transfer (LET)?

The amount of energy that radiation transfers to the material it passes through per unit length.

What is radioprotection?

The practice of protecting patients, workers, and the public from potential harmful effects of ionizing radiation.

Who regulates radiation safety in the workplace?

Government agencies such as the Nuclear Regulatory Commission (NRC) and the Environmental Protection Agency (EPA) in the US.

What is ALARA?

An acronym for 'As Low As Reasonably Achievable' to minimize radiation exposure.

Define dose limit.

The maximum permissible exposure to radiation for individuals, usually outlined by regulatory bodies.

What is the relationship between distance and radiation exposure?

Inversely proportional; increasing distance decreases exposure due to the inverse square law.

What is shielding in radiology?

The use of materials to protect against ionizing radiation.

What materials are commonly used for radiation shielding?

Lead, concrete, and aluminum.

Explain scatter radiation.

Radiation that has been deflected from its original path after interacting with matter.

What is the purpose of a dosimeter?

To measure and record personal exposure to ionizing radiation.

What are some common types of dosimeters?

Film badges, thermoluminescent dosimeters (TLD), and electronic personal dosimeters.

Define the term radiographic contrast.

The difference in the brightness between adjacent areas on a radiographic image.

What factors influence radiographic contrast?

Radiation quality, image receptor sensitivity, and composition of the object being imaged.

What is a radiographic grid?

A device used to improve image quality by reducing scatter radiation reaching the film.

What is digital radiography?

A method that uses digital sensors instead of traditional film to capture images.

Describe image processing in radiology.

The manipulation of digital images to enhance quality and facilitate diagnosis.

What is fluoroscopy?

An imaging technique that provides real-time moving images of the interior of the body.

What is the significance of the S number in digital radiography?

It indicates the exposure level; lower numbers mean higher exposure and vice versa.

What is the role of a radiologic technologist?

To perform imaging examinations and ensure patient safety from radiation exposure.

What is the difference between radiology and radiotherapy?

Radiology involves using radiation for imaging; radiotherapy uses radiation for treatment.

How does magnetic resonance imaging (MRI) differ from X-ray?

MRI uses magnetic fields and radio waves, while X-ray utilizes ionizing radiation.

What does the term 'radiation dose' represent?

The amount of energy absorbed by the body from radiation.

What is the principle behind the use of contrast agents in radiology?

To enhance the visibility of specific structures in imaging.

Why is patient history important in radiology?

To assess contraindications and tailor the imaging approach.

What is radiation hormesis?

The hypothesis that low doses of radiation may have beneficial effects.

Explain the term 'radiation-induced cancer.'

Cancer caused by exposure to ionizing radiation.

What are the common symptoms of radiation sickness?

Nausea, vomiting, fatigue, and changes in blood cell counts.

What is the significance of a radiation safety officer (RSO)?

To oversee safety measures and compliance with radiation regulations.

Identify some key protective measures in radiology.

Lead aprons, thyroid collars, and shielding barriers.

What is patient consent in the context of radiology?

The process of informing patients and obtaining their agreement for imaging procedures.

Describe the use of radiology in emergency medicine.

To quickly assess injuries and conditions to guide immediate treatment.

What is the role of radiology in cancer diagnosis?

To detect tumors, assess their size, and determine staging.

How is radiation exposure measured over time?

Through cumulative dose measurements using dosimeters.

What does 'informed consent' mean in radiology?

A process where patients are educated about the risks and benefits before an imaging procedure.