Intro to radiology Wk 1

He discovered X-rays in 1895 and was awarded the first Nobel Prize for Physics in 1901.

Wilhelm Roentgen

Who created the first portable x-ray machine in WWI

Marie Currie

Used in WWI to locate bullets and someone noticed it outlined the GI tract creating GI imaging

Barium

Discovered while studying nuclear physics in the 1940s

MRI

adapted from the submarine sonar

ultrasound

images produced by ionizing radiation are called

conventional radiographs or more often plain films or Xray

What are the pros of plain films?

inexpensive and accessible

what are the cons of plain films?

limited range and radiation exposure

What are the common uses of conventional radiography?

Chest X-ray, plain films of the abdomen, and imaging of the skeletal system.

How does an X-ray work?

heated cathode filament --> electrons --> vacuum to tungsten anode --> stop at node and release energy as x ray photons

What is the term for x rays passing through the pt and the tissues absorb them differently based on density and atomic number

differential attenuation

What does contrast depend on?

tissue thickness, density, and atomic number

What are the five basic densities seen in conventional radiographs?

Air, Fat, Fluid or Soft Tissue, Calcium, and Metal.

What is the appearance of air on a conventional radiograph?

Air absorbs the least X-rays and appears the 'blackest'.

What is the appearance of fat on a radiograph?

Gray, somewhat darker than soft tissue

What is the appearance of fluid or soft tissue on a radiograph?

they appear the same due to having the same density

What is the appearance of calcium on a radiograph?

it is the most dense and absorbs most x rays

What is the appearance of metal on a radiograph?

usually absorbs and appears the whitest

uses ionizing radiation in performing real-time visualization of the body evaluating the motion of body parts and real time positioning changes of bones and joints

fluoroscopy

What is the primary limitation of plain film chest imaging?

Limited range of densities and reliance on ionizing radiation.

What is differential attenuation in X-ray imaging?

It refers to how different tissues absorb X-rays based on their density and atomic number.

What is the role of radiologic technologists in the imaging process?

To assist in the imaging process and ensure proper technique and patient care.

What is the importance of patient positioning in X-ray imaging?

Proper positioning is crucial for obtaining accurate images and minimizing errors.

What does the term 'poor inspiratory result' refer to in chest X-rays?

It indicates inadequate lung inflation during the X-ray, which can obscure findings.

What is the appearance of metal on a conventional radiograph?

Metal usually absorbs all X-rays and appears the 'whitest'.

What is the function of the X-ray machine's cathode filament?

It releases electrons when heated, which are then accelerated towards the anode.

How does the X-ray beam interact with the body?

Tissues absorb X-rays differently, leading to image formation based on density.

What does the term 'skiagraphy' refer to?

The original name for the field of radiology, meaning 'shadow writing'.

What is the role of interprofessional collaboration in patient care?

To enhance communication and care coordination among healthcare professionals.

narrow beam of x rays rotated around the body to generate cross sectional images or slices of the body

CT scans

What type of images do CT scanners generate?

Cross-sectional images or tomographic images

How does a CT scanner create a three-dimensional image?

By digitally stacking cross-sectional slices collected by the machine's computer

What is the primary advantage of CT scans over conventional x-rays?

CT scans provide more detailed information and allow for easier identification of structures and abnormalities.

What type of radiation do CT scanners use?

Ionizing radiation (x-rays)

What does increased attenuation in a CT scan indicate?

Denser substances that absorb more x-rays appear as whiter densities.

What is post-processing in CT scanning?

A benefit that allows for additional manipulation of raw data to optimize visibility of abnormalities.

Scans can be windowed to optimize the visibility of different types of pathology after obtained allowing for additional manipulation of raw data…

post-processing

What are the three planes in which volumetric data from CT can be viewed?

Axial, Sagittal, Coronal

What is a new application of CT imaging?

Virtual colonoscopy, virtual bronchoscopy, cardiac calcium scoring, or CT coronary angiography.

What does air and fluid look like on a CT

Air = black Fluid = white

What does MRI utilize to produce images?

The potential energy stored in the body's hydrogen atoms.

What is a major advantage of MRI over CT?

MRI does not use ionizing radiation and provides higher contrast between soft tissues.

What are some disadvantages of MRI?

Not widely available, expensive, requires site construction, and has high ongoing operating costs.

An unstable form of an element that emits radiation from its nucleus as it decays.

radioactive isotope

radioisotopes used in clinical nuclear medicine are also referred to in a

radionuclides, radio tracers, tracers

Naturally occurring radioisotopes include:

uranium and thorium

Combinations of radioisotopes attached to pharmaceuticals that concentrate in specific body tissues.

radiopharmaceutical

What body organs have specific affinity for what chemicals?

thyroid-iodine

brain - glucose

bones- phosphates

lung - varys

produces 3D images that depict the bodies biochemical and metabolic processes performed with a positron producing radioisotope attached to a targeting pharmaceutical

PET scans

The most commonly used target molecule in PET scanning is an analog of glucose called

fluorodeoxyglucose (FDG)

What is the primary use of PET scans?

Diagnosis and treatment follow-up of cancer.

nuclear medicine technique combining a PET scanner and a CT scanner to acquire sequential images from both devices in same session and are combined into single image

PET-CT

PET-CT is used in oncology for ?

cancer staging, surgical planning, and radiation therapy

What biological effect can radiation cause?

Cell mutations that could lead to cancer or anomalies.

studies with x rays should be avoided during?

teratogenic times such as pregnancy

What modalities use ionizing radiation

CR, CT, Fluoroscopy

What are the three fates of radiation during an imaging procedure?

Transmitted radiation, absorbed radiation, and scatter radiation.

the radiation that passes through the patient and interact with the detector to create the image

transmitted radiation

the radiation that interacts with the tissues of the patient depositing its energy in those tissues and is the source of patient radiation exposure

absorbed radiation

not transmitted or absorbed by the patient

scatter radiation

How is absorbed radiation measured

by the absorbed dose (Gy) per unit mass

What is the relationship between radiation dose and cancer risk?

The probability of cancer development increases with higher doses of radiation.

What is a common source of radiation for humans?

Medical imaging tests account for a significant portion of annual radiation exposure.

What is the effect of radiation on slowly dividing mature cells?

They have a low sensitivity to radiation damage.

What are the most radioactive organs?

bone marrow, colon, lung, female breasts, stomach, and childhood thyroid

What is the safe annual radiation dose for a person in the U.S.?

Approximately 3.5 mSv.

What is the maximum safe occupational exposure to radiation?

20 mSv.

What is the latent period for cancer development after radiation exposure?

There can be a 10-20 year latent period.

What is the energy unit used to measure radiation dose?

Gray (Gy), while damage is measured in Sievert.

As Low As Reasonably Achievable; it aims to limit radiation exposure while obtaining high-quality images.

ALARA

What are the 3 radiation safety practices?

1. managing time of exposure

2. increasing the distance from the source

3. using appropriate shielding materials

What is the risk of mortality from radiation-induced cancer in children compared to adults?

Children have a 3 to 5 times higher risk of mortality from radiation-induced cancer than adults.

What potential effects can radiation exposure have on a fetus during the first 3-4 weeks of pregnancy?

Possible spontaneous abortion with increasing dose.

What are the potential effects of radiation exposure during weeks 5-10 of pregnancy?

Possible malformations increasing in likelihood as dose increases.

What risks are associated with fetal radiation exposure during weeks 11-17 of pregnancy?

Risk of diminished IQ or mental retardation increases with dose.

What is the purpose of intravenous contrast in CT scanning?

To yield more diagnostic information that is more easily detectable.

CT scans performed with intravenous administration of iodinated contrast material.

contrast-enhanced CT scans

What is the composition of iodinated contrast used in CT scans?

Nonionic, low-osmolar solutions containing a high concentration of iodine.

What is the purpose of oral contrast in CT scanning?

To define the bowel for abdominal and pelvic CT imaging.

What are the two types of oral contrast that may be used?

Dilute solution of barium sulfate or iodine-based, water-soluble contrast.

What can happen in patients with compromised renal function when using iodinated contrast?

It can produce a nephrotoxic dose-related effect resulting in acute tubular necrosis.

What mild side effects can occur from iodinated contrast administration?

Feeling of warmth, nausea and vomiting, local irritation, itching, and hives.

Who is at higher risk for contrast reactions?

Asthmatics and those with a history of severe allergies or prior reactions to intravenous contrast.

What severe reactions can occur from contrast administration?

Intense bronchospasm, laryngeal edema, circulatory collapse, and very rarely, death.

Accumulation of fluid in the pericardial sac due to various causes like inflammation or malignancy.

pericardial effusion

What is the pathophysiology of pericardial effusion

rising intrapericardial pressure --> impaired diastolic filing

• If acute --> cardiac tamponade --> < preload, < cardiac output, shock

Chronic myocardial pressure or volume overload leads to chamber dilation and/or hypertrophy.

cardiac enlargement

Hypertension -->

concentric LV hypertrophy

valvular disease -->

eccentric dilation

cardiomyopathy -->

reduced contractility --> heart failure

What is the alveolar pattern in pulmonary infiltrate?

Alveoli fill with pus, blood, or fluid, impairing gas exchange.

What does the interstitial pattern in pulmonary infiltrate indicate?

Thickening of alveolar septa from inflammation, fibrosis, or lymphatic congestion.

When you hear or see the words HAZY OPACITY think?

pneumonia !!!!

Dilation of upper lobe veins due to elevated left atrial pressure backing up into pulmonary veins causing pulmonary venous hypertension and left sided heart failure

cephalization