2025年3月15日 · Half-value layer (HVL) is the thickness of a material required to reduce the air kerma of an X-ray or gamma-ray beam to half its original value. HVL is most accurately …

2017年12月1日 · In order to perform quality assurance tests, estimate absorbed doses in patients, and evaluate computed tomography (CT) number accuracies, we first need to determine the …

2014年1月1日 · Using a real-time dose probe and an assembly of aluminum filters, the HVL can be measured on a clinical CT scanner. HVL measurements were evaluated with both a real …

Half value layer (HVL) is measured experimentally by placing sheets of metal in the beam; HVL is a surrogate measure of beam quality. HVL is higher for a harder beam and lower for a softer …

半值层（缩写为hvl）是现代成像中使用的一种度量。 它表示将特定辐射减少一半强度水平的材料的厚度。 hvl可以通过实验或数学方法确定。 推导半值层公式。

2020年8月1日 · There is no need for X-ray tubes to be fixed in the service mode. This study aimed to compare two methods of assessing the half-value layer (HVL) for computed …

2019年2月1日 · Computed tomography (CT) is a method of imaging used for the diagnosis and treatment of diseases. Different from the conventional diagnostic radiology equipment, where …

The half-value layer (HVL) is the thickness of a material that de- creases the intensity of X-rays passing through it to half of their original air-kerma ( K ̇

2000年8月8日 · The purpose of this paper is to determine the accuracy and reproducibility of two noninvasive methods of measuring half-value layer (HVL), ring and localization, compared with …

2014年1月20日 · Half-value layer (HVL) measurements on commercial whole body computer tomography (CT) scanners require serial measurements and, in many institutions, the …