Related Experiment Video
Updated: May 6, 2026
10:33
Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation
Published on: September 4, 2017
19.7K
Hounsfield units variations: impact on CT-density based conversion tables and their effects on dose distribution
B Zurl1, R Tiefling, P Winkler
1Department of Therapeutic Radiotherapy and Oncology, University Medical School of Graz, Comprehensive Cancer Center Graz, Auenbruggerplatz 32, 8036, Graz, Austria, brigitte.zurl@klinikum-graz.at.
Summary
Different CT scanning protocols cause Hounsfield Unit (HU) variations, leading to radiation therapy dose errors. Implementing specific conversion tables can minimize these systematic dose errors.
Area of Science:
- Medical Physics
- Radiation Oncology
- Radiological Imaging
Background:
- Computed Tomography (CT) scanning protocols significantly influence Hounsfield Unit (HU) values.
- Variations in HU values can impact radiation dose calculations in treatment planning.
Purpose of the Study:
- To determine the dose error margins in radiation therapy planning.
- To investigate the impact of CT scanning protocol variations on Hounsfield Unit (HU) values and subsequent dose calculations.
Main Methods:
- Generated conversion tables for radiation dose calculations based on different clinical CT protocols.
- Tested tables on a phantom and recalculated plans for 28 patients who received head radiation therapy after an incorrect protocol was used.
Main Results:
- CT parameter variations caused HU errors up to 25.6% for densities >1.1 g/cm(3), particularly with tube voltage changes.
- Dose differences ranged from 0.3% to 1.5% for varying phantom layer thicknesses.
- Patient data recalculation showed an overdose of 1.3% to bone and 0.7% to brain tissue.
Conclusions:
- Different CT scanning protocols can lead to significant HU variations (up to 20%) and a mean systematic dose error of 1.5%.
- Specific conversion tables and automatic CT scanning protocol recognition are recommended to reduce these dose errors.
More Related Videos
Related Concept Videos
01:10Computed Tomography
7.6K
Tomography refers to imaging by sections. Computed tomography (CT) is a non-invasive imaging technique that uses computers to analyze several cross-sectional X-rays to reveal minute details about structures in the body.
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
7.6K
02:59Biological Effects of Radiation
15.5K
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they...
15.5K
01:30Radiological Investigation I: X-ray and CT
1.8K
Radiological investigations, including X-rays and computed tomography (CT) scans, are critical for diagnosing and evaluating various medical conditions. These imaging techniques provide valuable insights into the body's internal structures, aiding in the detection of abnormalities, assessment of disease progression, and development of treatment strategies. This article delves into two primary radiological investigations, chest X-rays and CT scans, outlining their purpose, procedures, and...
1.8K
01:27Imaging Studies III: Computed Tomography
902
DefinitionComputed Tomography (CT) of the genitourinary (GU) tract is a non-invasive imaging modality that utilizes X-rays and computer processing to generate detailed cross-sectional images of the urinary system, encompassing the kidneys, ureters, bladder, and adjacent structures such as the adrenal glands.PurposeCT scans of the GU tract serve several diagnostic and therapeutic purposes, including:Diagnosis of Urinary Tract Diseases: Detects kidney stones, tumors, cysts, and congenital...
902
01:21Dose Response Curve: Conventional Versus Nonmonotonic
383
The correlation between a drug's dosage and its impact on a biological system is a cornerstone of pharmacology and toxicology. Conventional dose–response curves, which include graded and quantal relationships, are key to this understanding. Graded dose–response curves depict the spectrum of a biological reaction to different doses within an individual, indicating that as the drug dosage increases, so does the intensity of the response. On the other hand, quantal dose–response...
383
01:21Dose Size and Dosing Frequency: Determination Methods
817
Determining the optimal dose size and dosing frequency in pharmacotherapy is crucial for achieving therapeutic effectiveness while minimizing adverse effects. This article explores the methodologies employed in determining these parameters, focusing on their significance and interplay to tailor dosing regimens.Dose Size: Dose size refers to the amount of a drug administered in a single dose. It is determined based on the drug's pharmacodynamics and pharmacokinetics properties and...
817