RT 201: IMAGING SCIENCE AND INFORMATICS
MIDTERM LECTURES
INSTRUCTOR: DANNALYN D. IBAÑEZ RRT, MAEM, PhD
FIRST SEMESTER | A.Y. 2022 - 2023
Lesson 1: MEDICAL IMAGE DATA Vomex (Volume Element)
- is related to both the pixel size and slice
Medical Imaging thickness
- is the process of converting tissue
- coined as a 3-D equivalent of pixel
characteristics into a visual image.
- part of the body being imaged → visual image
Digital Imaging
- is a numerical representation of an image via
a set of picture elements known as pixels.
Bit Depth
- corresponds to the number of gray levels in
an image
- The more gray levels possible, the more
Pixels of medical images are typically so small and so
range a user has when working with the
numerous that, when displayed on a computer
image, specifically adjusting the window and
monitor, they appear to merge into a smooth
level of the image (brightness and contrast)
continuous image.
More pixels = better image
Smaller pixel size = better resolution
Matrix More gray levels = better visualization of image
- is the number of pixels along the length (because details can be seen significantly)
(columns) and width (rows) of the image.
APPEARANCE OF DIGITAL IMAGES
The characteristics of a digital image: Matrix size,
Pixel size, and the Bit Depth can affect the
appearance of the digital image (spatial resolution
and its density resolution).
IMAGE QUALITY FACTORS
• Resolution
• Contrast
Pixel (Picture Element)
• Noise
- is the element that makes up the image
• Artifacts
matrix, each pixel is a respective value that
will represent a brightness level.
, RT 201: IMAGING SCIENCE AND INFORMATICS
MIDTERM LECTURES
INSTRUCTOR: DANNALYN D. IBAÑEZ RRT, MAEM, PhD
FIRST SEMESTER | A.Y. 2022 - 2023
RESOLUTION IMAGE NOISE
Is the ability to image two separate objects and visually Appears as an irregular granular pattern (salt-and-
distinguish one from the other. pepper distinction) in all images and degrades image
information.
Two categories of Resolution:
• Spatial Resolution
- refers to detail or sharpness of an image
(or visibility of detail)
- refers to the ability to image small
objects that have high subject contrast,
such as a bone-soft tissue interface, a
breast micro calcifications, or a calcified
lung nodule.
Insufficient no. of x-rays or less mill amperage (mA)
results to salt-and-pepper/grainy image
Low mA = grainy image
ARTIFACTS
Is a structure or an appearance that is not normally
present on the radiograph or image and is produced by
artificial means.
Hand Artifacts
• Contrast Resolution
- refers to the differences in tissue contrast
that can be seen on the image.
- refers to the ability to distinguish
anatomical structures of similar subject
contrast such as liver-spleen and gray-
white matter. Exposure Artifacts
Processing Artifacts
CONTRAST
Is the difference in the intensity of adjacent regions of
the image.
IMAGE QUALITY DESCRIPTORS
In CR image:
• Spatial resolution,
• Density resolution,
• Noise,
• Artifacts,
• Detective Quantum Efficiency
Reducing tube voltage (kV) increases image contrast
(right) compared with higher tube voltage (left).
MIDTERM LECTURES
INSTRUCTOR: DANNALYN D. IBAÑEZ RRT, MAEM, PhD
FIRST SEMESTER | A.Y. 2022 - 2023
Lesson 1: MEDICAL IMAGE DATA Vomex (Volume Element)
- is related to both the pixel size and slice
Medical Imaging thickness
- is the process of converting tissue
- coined as a 3-D equivalent of pixel
characteristics into a visual image.
- part of the body being imaged → visual image
Digital Imaging
- is a numerical representation of an image via
a set of picture elements known as pixels.
Bit Depth
- corresponds to the number of gray levels in
an image
- The more gray levels possible, the more
Pixels of medical images are typically so small and so
range a user has when working with the
numerous that, when displayed on a computer
image, specifically adjusting the window and
monitor, they appear to merge into a smooth
level of the image (brightness and contrast)
continuous image.
More pixels = better image
Smaller pixel size = better resolution
Matrix More gray levels = better visualization of image
- is the number of pixels along the length (because details can be seen significantly)
(columns) and width (rows) of the image.
APPEARANCE OF DIGITAL IMAGES
The characteristics of a digital image: Matrix size,
Pixel size, and the Bit Depth can affect the
appearance of the digital image (spatial resolution
and its density resolution).
IMAGE QUALITY FACTORS
• Resolution
• Contrast
Pixel (Picture Element)
• Noise
- is the element that makes up the image
• Artifacts
matrix, each pixel is a respective value that
will represent a brightness level.
, RT 201: IMAGING SCIENCE AND INFORMATICS
MIDTERM LECTURES
INSTRUCTOR: DANNALYN D. IBAÑEZ RRT, MAEM, PhD
FIRST SEMESTER | A.Y. 2022 - 2023
RESOLUTION IMAGE NOISE
Is the ability to image two separate objects and visually Appears as an irregular granular pattern (salt-and-
distinguish one from the other. pepper distinction) in all images and degrades image
information.
Two categories of Resolution:
• Spatial Resolution
- refers to detail or sharpness of an image
(or visibility of detail)
- refers to the ability to image small
objects that have high subject contrast,
such as a bone-soft tissue interface, a
breast micro calcifications, or a calcified
lung nodule.
Insufficient no. of x-rays or less mill amperage (mA)
results to salt-and-pepper/grainy image
Low mA = grainy image
ARTIFACTS
Is a structure or an appearance that is not normally
present on the radiograph or image and is produced by
artificial means.
Hand Artifacts
• Contrast Resolution
- refers to the differences in tissue contrast
that can be seen on the image.
- refers to the ability to distinguish
anatomical structures of similar subject
contrast such as liver-spleen and gray-
white matter. Exposure Artifacts
Processing Artifacts
CONTRAST
Is the difference in the intensity of adjacent regions of
the image.
IMAGE QUALITY DESCRIPTORS
In CR image:
• Spatial resolution,
• Density resolution,
• Noise,
• Artifacts,
• Detective Quantum Efficiency
Reducing tube voltage (kV) increases image contrast
(right) compared with higher tube voltage (left).
