Computed Tomography (CT) is an essential imaging modality that aids in the diagnosis and management of various medical conditions. Ensuring the accuracy and consistency of CT images is crucial for providing optimal patient care. To achieve this, healthcare facilities follow rigorous quality control practices outlined by reputable organizations such as the American College of Radiology (ACR) and the Intersocietal Accreditation Commission (IAC). In this blog, we will explore the recommended daily, weekly, and monthly quality control practices for CT imaging, as per the ACR and IAC guidelines.

Daily Quality Control Practices

  1. Check CT Scanner Warm-up: At the beginning of each day, perform a warm-up procedure recommended by the CT scanner manufacturer. This ensures that the system is functioning correctly and is ready for patient imaging. Please follow the recommendations from the manufacturer as these procedures vary.
  2. Monitor Image Quality: Routinely evaluate the image quality throughout the day by acquiring and reviewing image quality assurance phantoms. These phantoms mimic patient anatomy and allow for the assessment of spatial resolution, noise, and artifacts.
  3. Check Display Monitors: Ensure the CT workstation’s display monitors are calibrated and functioning optimally to accurately represent the acquired images.
  4. Review Radiation Dose: Keep track of patient radiation dose levels for each scan and compare them against established reference levels and local diagnostic reference levels (DRLs). This helps ensure that the radiation dose is within acceptable limits. This software is usually built into all XR-29 compliant systems from the manufacturer. Third party software is also available.
  5. QC procedures must be recorded and saved. This can be in physical form or digitally. Please consult your states governing body for specific rules, regulations and timelines for keeping maintenance records.

Weekly Quality Control Practices

  1. Image Uniformity: Assess image uniformity by acquiring and analyzing uniformity phantoms. This test helps identify any inconsistencies in the CT scanner’s response to different tissue densities.
  2. Slice Thickness Verification: Verify the accuracy of slice thickness settings by acquiring images of a slice thickness phantom and comparing the results to the intended settings.
  3. Detector Artifacts: Perform detector artifact tests to detect any irregularities or malfunctions in the CT detector array.
  4. Radiation Output: Measure the CT scanner’s radiation output to ensure it complies with established standards and guidelines.

Monthly Quality Control Practices

  1. Spatial Resolution Evaluation: Evaluate the CT scanner’s spatial resolution using high-contrast phantoms and compare the results against recommended values.
  2. CT Number Accuracy: Verify the CT number accuracy using a quality control phantom with known CT numbers for different materials. This ensures that Hounsfield Units (HU) are accurately represented in the images.
  3. Noise Assessment: Measure the noise level in the CT images using a phantom with a uniform attenuation coefficient. This helps ensure that the noise remains within acceptable limits.
  4. Image Artifacts: Identify and address any image artifacts that may arise during CT scanning, as they can affect image quality and diagnostic accuracy.

Conclusion

Maintaining a high standard of image quality in CT imaging is crucial for accurate diagnosis and optimal patient care. By adhering to the daily, weekly, and monthly quality control practices recommended by the ACR and IAC, healthcare facilities can ensure the reliability and consistency of their CT imaging systems. These practices not only safeguard the well-being of patients but also contribute to the overall efficiency and reputation of the healthcare institution.

Remember that specific guidelines and recommendations may vary slightly between different CT scanner models and manufacturers. Therefore, it is essential to consult the manufacturer’s documentation and the latest ACR and IAC guidelines for the most up-to-date and comprehensive quality control protocols. Regularly scheduled maintenance and adherence to these practices will help ensure the continued accuracy and safety of CT imaging for both patients and medical professionals.