SCIE10180 – Module 1: Introduction to Diagnostic Imaging Modalities – Vocabulary Flashcards

Vocabulary flashcards covering key terms from the lecture notes on diagnostic imaging modalities, professional bodies, and imaging concepts.

CAMRT

Canadian Association of Medical Radiation Technologists; national professional association for MRTs in Canada; oversees certification, advocacy, continuing education; student perks.

Sonography Canada

Represents diagnostic sonographers; credentials include CRGS®, CRCS®, CRVS®; provides CPD workshops, journal access, insurance.

OAMRS

Ontario Association of Medical Radiation Sciences; provincial body offering continuing education, lobbying, professional support; student perks include liability insurance and networking.

CMRITO

College of Medical Radiation and Imaging Technologists of Ontario; regulator that registers/licenses MRTs & DMS; upholds standards and ethics; investigates complaints to protect the public.

MRT

Medical Radiation Technologist; professional who operates imaging equipment safely, positions patients, and produces diagnostic-quality images.

DMS

Diagnostic Medical Sonography; ultrasound professionals licensed under relevant regulatory bodies; focuses on sonography/ultrasound imaging.

Imaging workforce in Canada

Approximately 25,750 MRTs in Canada; CAMRT has 11,000+ members; high exam volumes in CT and MRI reflect workforce demand.

Radiography/CT

Radiography uses X-rays for bones and trauma; CT uses X-rays and computer reconstruction to produce cross‑sectional slices; CT often employs spiral/helical scanning with slip rings.

MRI

Magnetic resonance imaging; uses magnetic fields and radio waves; excellent soft tissue detail; no ionizing radiation; longer scans and higher cost/access considerations.

Ultrasound

Ultrasound uses sound waves for real-time imaging; portable and safe with no radiation; operator-dependent and limited by gas/fat in the imaging field.

Nuclear Medicine

Uses radioactive tracers to assess physiological/metabolic function; imaging modalities include gamma cameras, PET, SPECT; can combine with CT (PET/CT) or MRI (PET/MRI); theranostics is a related concept.

Bremsstrahlung

X-ray photons produced by deceleration of electrons in the target material during X-ray production.

Characteristic radiation

X-ray photons produced when electrons fill vacancies in inner electron shells after interactions in the target.

CR

Computed Radiology; uses phosphor plates to store images which must be scanned to digital form.

DR

Digital Radiology; direct conversion to digital detectors with immediate image availability.

Attenuation

Reduction in X-ray intensity as it passes through tissue; bone attenuates most (appears white), followed by soft tissue, then air.

Contrast

Difference in attenuation between structures; determines visibility of tissues and lesions on the image.

kVp

Peak kilovoltage; controls beam energy/penetrability and image quality (higher kVp increases penetration).

mA

Tube current; number of electrons in the stream; affects X-ray production rate and image brightness.

mAs

Product of mA and exposure time; controls total X-ray quantity and patient dose.

SID

Source-to-Image Distance; distance from X-ray source to detector; influences magnification and patient dose (inverse square relationship).

Hounsfield Units (HU)

CT attenuation scale: air ≈ -1000 HU, water = 0 HU, bone ≈ +1000 HU; used to quantify tissue density.

Windowing

Adjusting the CT HU range displayed (window level/width) to highlight specific tissues for better visualization.

Slip ring technology

CT feature enabling continuous gantry rotation for spiral/helical scanning, increasing speed and reducing motion artifacts.

Helical scanning

CT data acquisition in a spiral path around the patient, enabling 3D reformations and faster imaging.

X-ray basics

Electromagnetic radiation with short wavelength that passes through the body to create shadow images on detectors.

X-ray production steps

Cathode releases electrons; acceleration to anode; collision with tungsten target produces X-rays (Bremsstrahlung and Characteristic); only about 2–5% of energy becomes X-rays; rest becomes heat.

Detectors

CR (Computed Radiology) uses phosphor plates that must be scanned; DR (Digital Radiology) uses direct detectors with immediate digital output.

Case Activity – Best Modality

Examples: wrist fracture best with radiography; severe headache with CT or MRI; pregnant abdominal pain with ultrasound; chest pain with Nuclear Medicine or CT angiography.

Theranostics

Concept in Nuclear Medicine combining diagnosis and targeted therapy using radiopharmaceuticals.

PET

Positron Emission Tomography; functional imaging using radiotracers, often combined with CT or MRI (PET/CT, PET/MRI).

SPECT

Single Photon Emission Computed Tomography; functional imaging using gamma cameras, often fused with CT (SPECT/CT).

PET/CT

Hybrid imaging combining metabolic information from PET with anatomic detail from CT in one exam.

PET/MRI

Hybrid imaging combining PET functional data with high-contrast MRI for both functional and soft-tissue detail.