RADS 301

Which modalities use ionizing radiation?

X-Rays, CT, PET

What are the 3 anatomical planes?

1. Sagittal Plane
2. Frontal Plane
3. Transverse Plane

Highest to lowest radiodensity

Metal, bone, water/soft tissue, fat, air

What does B-mode stand for in ultrasound?

Brightness mode

What does a Doppler ultrasound measure? 

Blood flow (mcat moment)

Which of the following statement is true about protons of the body?
a) They are always aligned and stationary.
b) They have intrinsic spin
c) They cannot be manipulated by external magnetic field.
d) The time protons take to recover from displacement to its original alignment with the external magnet field is called T2.

b) They have intrinsic spin

Which of the imaging modalities was the first to be invented?

X-Ray (radiograph / plain film)

Endovascular thrombectomy (EVT) is primarily used to treat which condition?

Acute Ischemic stroke

Which of the following statement is true about Bremsstrahlung radiation?
a) Bremsstrahlung radiation has discrete peaks.
b) Bremsstrahlung radiation is produced when high-energy electrons are deflected by atomic nuclei.
c) Bremsstrahlung radiation is the produced by smashing an electron into an orbital electron.
d) Bremsstrahlung radiation is the result of transition of an outer shell electron to the inner shell.

b) Bremsstrahlung radiation is produced when high-energy electrons are deflected by atomic nuclei.

Which of the following types of radiation are considered ionizing?
1. X-rays
2. Gamma rays
3. Alpha particles
4. Neutrons
5. Microwave

1, 2, 3, 4

Which of the following statements is true about ionizing radiation?
a) The same dose of different types of ionizing radiation causes the same effect on tissue.
b) Ionizing radiation only causes damage to tissue by directly targeting DNA.
c) Generally speaking, the slower the cells divide, the less sensitive they are to ionizing radiation.
d) None of the above

c) Generally speaking, the slower the cells divide, the less sensitive they are to ionizing radiation.

Which of the following is NOT a source of natural background radiation?
a) Radon gas
b) Cosmic rays
c) Radioactive material in the soil
d) Medical X-rays

d) Medical X-rays

Which of the following statements is true about radiation injury?
a) All forms of radiation injury cause immediate tissue damage
b) Radiation injury affects all tissues in the body equally
c) Radiation exposure is safe during pregnancy, as it only affects the mother and not the fetus
d) Exposure to low doses of radiation over time may increase the risk of cancer

d) Exposure to low doses of radiation over time may increase the risk of cancer

Which of the following statements is true about ionizing radiation?
a) The same dose of different types of ionizing radiation causes the same effect on tissue.
b) Ionizing radiation only causes damage to tissue by directly targeting DNA.
c) Generally speaking, the slower the cells divide, the less sensitive they are to ionizing radiation.

c) Generally speaking, the slower the cells divide, the less sensitive they are to ionizing radiation.

Which of the following is NOT a source of natural background radiation?
A) Radon gas
B) Cosmic rays
C) Radioactive material in the soil
D) Medical X-rays

D) Medical X-rays

Which of the following statements is true about radiation injury?
A) All forms of radiation injury cause immediate tissue damage
B) Radiation injury affects all tissues in the body equally
C) Radiation exposure is safe during pregnancy, as it only affects the mother and not the fetus
D) Exposure to low doses of radiation over time may increase the risk of cancer

D) Exposure to low doses of radiation over time may increase the risk of cancer

You may have heard that people get a stent after a heart attack. What is the primary function of a coronary stent?

To open a blockage in the coronary artery

Concerning muscles visualized by ultrasound, which statement is NOT correct?
a) Appears the same, independent of the probe angle
b) Appears different, dependent on probe position
c) Muscles are connected to bone via tendon
d) Muscle tears can be diagnosed easily by ultrasound

a) Appears the same, independent of the probe angle

What Artifact is this from and what is it?

MRI. Acoustic Shadowing.

When a object absorbs or strongly reflects the soundwaves

What is Echo delay

Transducer interprets as “farther” object location

What is Photoelectric effect?

An incoming X-ray photon is completely absorbed, ejecting an electron from the atom.

The atom becomes positively charged; the released photoelectron can cause further ionization. Ionizing radiation can remove electrons from atoms.

Explain photoelectric effect and tissue contrast

Photoelectric absorption increases strongly with atomic number:

• approximately Z³ at a fixed photon energy. Tissue density also affects attenuation.
• Bone stops more X-rays and appears white; air transmits more and appears black. 

What is Z³ 

describes how strongly a material absorbs X-ray photons

Bones have Z = 20, while soft tissues have Z = 7.4

Types of ionizing radiation

Photons (X-ray and Gamarays)

The rest are therapy purpose

What is Compton Scatter? In context of X-ray

"A photon transfers part of its energy to an electron, then continues in a different direction with less energy. Scattered photons reaching the detector reduce contrast.

https://howradiologyworks.com/scatter-in-x-ray-imaging/"

Who discovered radiology? And how?

Roentgen from Germany. Somehow discovered X-rays while experimenting with cathode rays. A nearby fluorescent screen illuminated, revealing radiation that could penetrate objects and show internal structures.

Which Imaging does not use Ionizing radiation?

Ultrasound (Sound) and MRI (Magnetic fields)

What does it mean when we say attenuated?

X-rays that the body is absorbed. Indicated by the colour white.

What does it mean when we say Radiolucent?

less attenuation = darker, such as air.

What the Strengths of CT

Provides detailed cross-sectional anatomy aka 3D Images

Used for trauma and acute care

Radiographs vs Cts

X-rays: Cheaper, quicker, and low radiation

CT: Rotating x-ray, longer, detailed, higher radiation

Name of CT image?

Coronal

Name of CT image?

Sagittal

Name of CT image?

Axial/Transverse

Answer

On CT, the measure of density is called a

Hounsfield Unit (HU)

What are Contrast studies?

Distinguish structures that look somewhat similar. E.g IV contrast to enhance blood vessels

What is MRI

MRI uses a strong magnet and radiofrequency pulses to generate signals from hydrogen nuclei, abundant in water and fat.

Different sequences emphasize different tissue properties.

Excellent soft-tissue contrast; no ionizing radiation.

Explain the difference between T1 vs T2 MRI

T1:
Fluid is Dark
Fat is Bright
Focuses on Anatomy


T2
Fluid is Bright
Fat is Bright
Focuses on Fluid, edema, pathology

Strengths and Weakness for MRI

Strengths: No exposure to ionizing radiation, good for soft tissues

Weakness: Expensive, long wait time, longer images, metal complication (magnet)

Explain Ultrasound

Uses high frequency sound waves to travel to generate an image

Cheap, no radiation, and real time

ULTRASOUND EXPLAIN THE TWO TYPES OF ECHOES

Hyperechoic: Reflecting many echoes (e.g bone, fat, stones, air)

Hypoechoic: No echoes since ultrasound can pass thru tissue (fluid, black)

What are Acoustic windows

Fluid transmits sound well, allowing deeper structures to be examine

Explain the concept of Ultrasound frequency, depth, and zoom

Higher frequency gives better resolution but less penetration; lower frequency reaches deeper.

e.g using higher frequency on soft tissue, lower frequency on deeper organs

Pulse repetition frequency is separate: fewer pulses per second allow longer listening between pulses.

Read Zoom: Increase resolution interest of area
Write Zoom: Rescans smaller area

Ultrasound applications

Know pregnancy assessment, abdominal organs, heart function, muscles/tendons, and leg-vein clots

What is Echocardiography? What are the two types?

Ultrasound for the heart

TTE: Non invasive. Just chest

TEE: Invasive. In the esophagus

Why use echocardiography?

Echo shows both anatomy and function in real time: chamber size, wall thickness, contraction, valves, and blood flow. No radiation

Describe all the facts of Heart diseases

#1 CAUSE OF DEATH IN WOMEN

1 in 5 Women

What is Coronary calcification? WHats the screening?

Build of calcium and results in atherosclerotic plaque. CT scan.

Two Techniques for Radiographs

What is a supine chest radiograph?

Lying on the back. Position usually set to AP.

AP vs PA effects on imaging?

AP magnifies shadow by 20-25%

Basic Anatomy

Trachea LOL

Explain the Pleural Anatomy

Visceral pleura covers the lung; parietal pleura lines the chest wall.

Right tension pneumothorax

Air accumulates under pressure in the right pleural space. The key mechanism is loss of the normal pressure relationship keeping the lung expanded, followed by increasing pressure in a tension pneumothorax.

Spontaneous pneumothorax

It just happens randomy lol

CT with Contrast

Uses contrast material on blood. This is known as CTPA.

CT strengths and Weaknesses

StrengthsL Bone and Lung detail
Good contrast

Weakness:
Radiation & weight limit

What is a pulmonary embolism?

A pulmonary embolism blocks a pulmonary artery, commonly with a clot

Ray tracing and global illumination

Ray tracing simulates paths of light. Global illumination accounts for indirect lighting and interactions such as shadows and reflections.

Cinematic rendering

photorealistic-looking 3D images from cross-sectional data using lighting models

Main reason Cinematic rendering is better than xray?

Improved diagnosis reveal fractures are that cannot be detected via x-rays

Which complex injuries is cinematic rendering mostly used in?

Pelvic fractures

What is the main weakness of cinematic rendering

Potential for Artifacts: Over-processing could theoretically obscure some subtle details

Cinematic rendering vs Standard Volume rendering

Cinematic uses lighting, and is more computational

Volume uses less detail lighting and is less computational

What is the top grey matter in the brain called? And what’s its main purpose?

Pre-central gyrus. Motor control.

Give me definition of cerebellum

Balance and voluntary moves

Give me definition of Caudate and Lentiform Nuclei

Tuned movements

What is the grey matter in the brain called (bottom)? And what’s its main purpose?

Post-central gyrus. Sensation.

What is the white in the brain called?

Internal Capsule

Name the 4 motor control of the brain

Pre-central gyrus, internal capsule, midbrain, spinal cord

PIMPS without the P

What is Chest CT with contrast called?

Computed tomography Pulmonary angiography. Its non invasive

What is angiography?

The study of vessels

Which of the following type of imaging modality does NOT use ionizing radiation?
A. X-RAY
B. Computed tomography (CT)
C. MRI
D. Fluroscopy

C. MRI

Which of the following imaging modalities is used to screen breast cancer in general population
A. MRI
B. Fluroscopy
C. Ultrasound
D. Mammogram

D. Mammogram

Which of the following is not an advantage of xray?
A. Easily accessible
B. less radiation
C. bone visualization
D. soft tissue visualization

D. soft tissue visualization

Which imaging modality would you use for pulmonary embolism?
A. chest xray
B. PET/CT
C. CT
D. CTPA

D. CTPA

Which of the following imaging modalities is the best non-invasive test for confirming the direct presence of calcification in the coronary arteries?
A. nuclear cardiac imaging
B. catheter cardiac angiography
C. cardiac MRI
D. caridac computed coronary angiography tomography, ie cardiac CT

D. caridac computed coronary angiography tomography, ie cardiac CT

Which of the following statements is/are true about CT?
1. Uses ionizing radiation, Cross-sectional 2D images produced using many x-ray sources
2. Produce very detailed images comparing to X-ray (radiograph)
3. Most commonly used in diagnosis and monitoring of diseases. Variety of applications including different types of cancers, heart diseases, stroke, and etc

All of them are true!

The most common genetic cardiomyopathy with a prevalence of 1 in 500 in the general population is:
a) Coronary artery atherosclerosis
b) Mitral valve disease
c) Hypertrophic cardiomyopathy
d) Myocarditis

d) Myocarditis

What is pneumothorax

air in the pleural cavity

can see a thin white line
entire perimeter of lungs

causes lung to collapse

symptoms include shortness of breath and chest pain can be life threating

The skull protects the brain… = best imaged with

X-ray or CT

Brain tissue is “soft tissue” + water =

best imaged with MRI. CT is faster

Motor function involves the

Frontal Lobe

Sensory function involves the

Parietal Lobe

Neural foramen protects

nerve as it exits

What ultrasound advantages are listed?

No ionizing radiation, generally noninvasive external imaging, real-time images, low cost, and portability.

Why does CT reveal anatomy better than a single radiograph?

CT reconstructs cross-sectional slices, reducing the overlap of structures seen in a projection image.

Which generally attenuates more X-rays: bone or air?

Bone. More attenuation makes it appear whiter; air transmits more X-rays and appears darker.

What does TTE stand for, and where is the probe?

Transthoracic echocardiography; the probe is on the chest wall.

What does TEE stand for, and where is the probe?

Transesophageal echocardiography; the probe is in the esophagus, close to the heart.

Which pleural layer covers the lung surface?

Visceral pleura.

VP

Which pleural layer lines the inside of the chest wall?

Parietal pleura.

VP

Midbrain

Faced Joint