CT Competency - Basic - AskRadiographerDotCom

By completing this LMS, a radiographer should:
Understand the core principles of CT — how CT works, how images are formed, and what affects image quality.
Know how to use scanning parameters wisely — adjusting mA, kVp, pitch, and slice thickness to balance image quality and patient dose.
Prepare and position patients correctly — to ensure comfort, safety, and accurate imaging.
Apply radiation safety practices — keeping exposure “As Low As Reasonably Achievable (ALARA)” for every patient.
Recognize how images are reconstructed — and how post-processing tools (like windowing, MPR, 3-D) enhance diagnosis.
Follow standard CT protocols — understanding when and how to use contrast and proper scan ranges for each body region.
Maintain quality control — performing daily QC checks and recognizing common artefacts to ensure reliable, high-quality images.

Course Content

CT Physics & Principles
Basic physics, detectors, data acquisition, beam geometry Example: Helical vs axial scanning, attenuation, HU values

Introduction to CT Imaging
CT Numbers and the Hounsfield Scale
CT System Components
Image Formation: Voxels and Pixels
Image Reconstruction
Image Noise and Quality Factors
Bow-Tie Filter and Beam Shaping
Data Acquisition and Volumetric Imaging
Key Summary
Clinical Importance
Quiz 1 – Level Basic

Scanning Parameters & Optimization
mA, kVp, pitch, rotation time, AEC, reconstruction kernel Example: Image quality vs dose trade-off

Introduction
Tube Current (mA)
Tube Voltage (kVp)
Tube Current-Time Product (mAs)
Rotation Time
Pitch
Automatic Exposure Control (AEC)
Detector Configuration
Scan Field of View (SFOV)
Balancing Parameters for Image Optimization
Summary: Key Concepts
Practical Optimization Strategies
Quiz 2 – Level Basic

Patient Preparation & Positioning
Contrast prep, safety screening, immobilization Example: Positioning for head, chest, abdomen

Introduction
Purpose of Patient Preparation
Fasting Requirements
Pre-Contrast Safety Checks
Standard Patient Positioning
Removal of Metal Objects
Patient Centering in the Gantry
Scout (Topogram) Image
Patient Immobilization
Breath-Hold Instructions
Contrast Allergy & Safety
Summary: Key Concepts
Practical Tips for Radiographers
Quiz 3 – Level Basic

CT Radiation Dose & Safety
CTDIvol, DLP, DRL, ALARA, shielding Example: Dose reduction strategies

Introduction
Radiation Dose Metrics in CT
Principles of Radiation Protection
Parameters Affecting Patient Dose
Automatic Exposure Control (AEC)
Main Source of Radiation Risk
Shielding & Protection Measures
Dose Optimization Strategies
Typical CT Dose Values
Key Equations Summary
Summary: Key Concepts
Practical Safety Notes
Quiz 4 – Level Basic

Image Reconstruction & Post-Processing
FBP vs iterative, MPR, MIP, 3D rendering Example: Artifact reduction

Introduction
From Raw Data to Image
Reconstruction Algorithms
Reconstruction Kernel (Filter)
Slice Thickness and Reconstruction
Windowing: Display Controls
Multiplanar Reformation (MPR)
3-D Rendering and Volume Visualization
Interpolation in Helical CT
Hounsfield Units (HU) in Reconstructed Images
Post-Processing Workflow Summary
Summary: Key Concepts
Practical Tips for Radiographers
Quiz 5 – Level Basic

CT Protocols & Clinical Applications
Neuro, chest, abdomen, angiography Example: Protocol tailoring

Introduction
CT Brain Protocol
CT Angiography (CTA)
CT Chest Protocol
CT Abdomen and Pelvis Protocol
CT KUB (Kidneys, Ureters, Bladder)
CT Pulmonary Angiography (CTPA)
Contrast Enhancement Phases – Key Timing Summary
Positioning Guidelines for Common Examinations
Protocol Optimization Tips
Common Clinical Indications and Corresponding Protocols
Summary: Key Concepts
Practical Radiographer Notes
Quiz 6 – Level Basic

Quality Control & Troubleshooting
Artifacts, QC phantoms, calibration Example: Daily/weekly QA tests

Introduction
Objectives of CT Quality Control
Types of Quality Control Tests
Daily Quality Control Checks
Water Phantom Uniformity Test
Noise Measurement
Linearity Test
Geometric Accuracy Test
Calibration and Linearity Phantom
Common CT Image Artifacts & Troubleshooting
Troubleshooting Workflow for Radiographers
Radiation Safety Checks in QC
Documentation and Record-Keeping
Summary: Key Concepts
Practical Radiographer Notes
Quiz 7 – Level Basic

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Course Content

CT Physics & Principles Basic physics, detectors, data acquisition, beam geometry Example: Helical vs axial scanning, attenuation, HU values

Introduction to CT Imaging

CT Numbers and the Hounsfield Scale

CT System Components

Image Formation: Voxels and Pixels

Image Reconstruction

Image Noise and Quality Factors

Bow-Tie Filter and Beam Shaping

Data Acquisition and Volumetric Imaging

Key Summary

Clinical Importance

Quiz 1 – Level Basic

Scanning Parameters & Optimization mA, kVp, pitch, rotation time, AEC, reconstruction kernel Example: Image quality vs dose trade-off

Introduction

Tube Current (mA)

Tube Voltage (kVp)

Tube Current-Time Product (mAs)

Rotation Time

Pitch

Automatic Exposure Control (AEC)

Detector Configuration

Scan Field of View (SFOV)

Balancing Parameters for Image Optimization

Summary: Key Concepts

Practical Optimization Strategies

Quiz 2 – Level Basic

Patient Preparation & Positioning Contrast prep, safety screening, immobilization Example: Positioning for head, chest, abdomen

Introduction

Purpose of Patient Preparation

Fasting Requirements

Pre-Contrast Safety Checks

Standard Patient Positioning

Removal of Metal Objects

Patient Centering in the Gantry

Scout (Topogram) Image

Patient Immobilization

Breath-Hold Instructions

Contrast Allergy & Safety

Summary: Key Concepts

Practical Tips for Radiographers

Quiz 3 – Level Basic

CT Radiation Dose & Safety CTDIvol, DLP, DRL, ALARA, shielding Example: Dose reduction strategies

Introduction

Radiation Dose Metrics in CT

Principles of Radiation Protection

Parameters Affecting Patient Dose

Automatic Exposure Control (AEC)

Main Source of Radiation Risk

Shielding & Protection Measures

Dose Optimization Strategies

Typical CT Dose Values

Key Equations Summary

Summary: Key Concepts

Practical Safety Notes

Quiz 4 – Level Basic

Image Reconstruction & Post-Processing FBP vs iterative, MPR, MIP, 3D rendering Example: Artifact reduction

Introduction

From Raw Data to Image

Reconstruction Algorithms

Reconstruction Kernel (Filter)

Slice Thickness and Reconstruction

Windowing: Display Controls

Multiplanar Reformation (MPR)

3-D Rendering and Volume Visualization

Interpolation in Helical CT

Hounsfield Units (HU) in Reconstructed Images

Post-Processing Workflow Summary

Summary: Key Concepts

Practical Tips for Radiographers

Quiz 5 – Level Basic

CT Protocols & Clinical Applications Neuro, chest, abdomen, angiography Example: Protocol tailoring

Introduction

CT Brain Protocol

CT Angiography (CTA)

CT Chest Protocol

CT Abdomen and Pelvis Protocol

CT KUB (Kidneys, Ureters, Bladder)

CT Pulmonary Angiography (CTPA)

CT Physics & Principles
Basic physics, detectors, data acquisition, beam geometry Example: Helical vs axial scanning, attenuation, HU values

Scanning Parameters & Optimization
mA, kVp, pitch, rotation time, AEC, reconstruction kernel Example: Image quality vs dose trade-off

Patient Preparation & Positioning
Contrast prep, safety screening, immobilization Example: Positioning for head, chest, abdomen

CT Radiation Dose & Safety
CTDIvol, DLP, DRL, ALARA, shielding Example: Dose reduction strategies

Image Reconstruction & Post-Processing
FBP vs iterative, MPR, MIP, 3D rendering Example: Artifact reduction

CT Protocols & Clinical Applications
Neuro, chest, abdomen, angiography Example: Protocol tailoring

Quality Control & Troubleshooting
Artifacts, QC phantoms, calibration Example: Daily/weekly QA tests