The ability to see inside the body has allowed great improvements in non-invasive diagnostics. X-rays were discovered in the late 1800’s and gave the first look inside the body without a scalpel. 70 years later computer tomography was discovered allowing full three dimensional views inside the body. Around the same time work began towards the development of an MRI machine which gives 3D images inside the body without the need for ionizing radiation.
CT scanners have been around for 40 years and have improved in increased speed and reduced radiation exposure. While there are still advancements to be made with multi-detector machines the technology is mature and a great way to obtain 3D images of bones and other materials with high mineral concentrations. Despite all the improvements a CT scan still delivers a large radiation dose.
Magnetic Resonance Imaging
While a CT scan gives very crisp images of bones other soft tissue remains dark and difficult if not impossible to distinguish. While MRI machines are a fair bit more complex and expensive they do give good images of soft tissue as they measure the time it takes for a hydrogen atom to re-align to the bores magnetic field. By varying the settings different types of soft tissue can be highlighted. MRI technology still has a great deal of potential with stronger magnetic fields and specialised applications like functional MRI and gaited MRI.
Once you have the image data there is a great number of ways that it can be manipulated. Traditionally a radiologist would look at the scan data slice by slice using his/her specific knowledge and training to detect abnormalities and make a prognosis. Today with the advent of common high power computers and advanced image processing software various tissues can be delineated (segmented) from the scan data. This process of segmentation can be manual, automatic or semi-automatic. Here at Medical Models our primary use is to delineate various bones from the other tissue. We use specialized software that allows a few initiation points and lines (seeds) to give the software a starting point. The volumetric data is thus separated into bone and non-bone. These bones can then be exported as 3D models and printed on one of our printers.
While outside of our current software; CT and MRI scans can be registered together to give the benefit of both a CT scan (bones) and MRI (soft tissue). This is fairly un-common but has a great deal of potential for increased detail and possibilities.