Graphics Reference
In-Depth Information
because it offers a turnaround strategy for our species, a practical way for us
to it in and lourish on this planet by emulating 3.8 billion years of brilliant
designs and strategies.”
10
Shades of gray: Taking pictures inside the body
If there's no design software for body parts, how is it possible that people
today are able to print teeth and bone replacements? How did the surgeons
who performed the titanium jaw replacement manage to 3D print the exact
shape of the replacement jaw? Simple. They CT scanned the patient's body,
captured the image data in a ile, and then massaged the image ile into a ile
format that could guide a 3D printer.
Medical imaging technology, fueled by massive increases in computing
power and new graphics algorithms, has made it possible for us to look more
closely inside the body than ever before. Medical scans pass beyond the outer
covering and look deep inside an organ to depict its hard and soft tissue, air
spaces and tears and blockages. X-rays, the oldest and most widely used form
of medical imaging, pass an electromagnetic beam through the body.
Ultrasound is another widely used imaging technique. Ultrasound works
like a bat navigating its way through the dark by clicking out sound waves
that bounce off of tissues and provide information about its shape and surface
details. Another widely used imaging technology, medical resonance imaging,
or MRI, magnetizes protons in the body's water molecules and transforms
their vibrations into high-resolution images of the organs and soft tissues.
Another imaging technique called positron emission tomography, or PET,
detects gamma rays from radioactive material that's swallowed by or injected
into the patient and is captured by a gamma ray cameras.
If you have ever watched a medical crime movie or viewed your own MRI or
CT scan images, you probably noticed that a medical image isn't one picture,
but instead, consists of dozens of images, each depicting a single cross section
of a body part. Medical images such as MRIs and CT scans depict the body
in hundreds of shades of grey. Bone appears white. Soft tissue resembles the
subtle color variations of the sky on an overcast day. Voids, such as the insides
of the lungs, appear as lat black.
In a medical image, different cell types that share a similar physical density
appear in the image as nearly identical shades of gray. These confusing shades
of gray are a major obstacle to turning image data into a 3D computer model
