3.2. Voxels

Voxels: Extension to 3D—volumetric pixels represent a small cube of material in the scanned object. Medical 3D data consists of stacked imaging slices, each with an array of voxels describing tissue properties.

Voxels are the three-dimensional counterparts to the two-dimensional pixels found in digital images. In medical imaging, a voxel represents a cube-shaped volume of tissue or material. While pixels provide information for a specific position in a 2D scan (like a CT or MRI scan), voxels extend this concept into three dimensions. Each voxel holds data about the characteristics of the material it represents, such as density or color, depending on the imaging modality. Medical 3D data is typically compiled from multiple 2D slices, creating a stack of voxels that describe various tissue properties of the scanned object, like a cube made up of smaller cubes that build a larger 3D picture.

Imagine a child's toy made of small building blocks. Each block represents a voxel, and when stacked together, they form a complete shape, like a castle or a spaceship. Just as the blocks' arrangement creates a larger structure, the three-dimensional array of voxels forms a full representation of a patient's anatomy in medical imaging.

Scans: CT or MRI scanners generate DICOM image stacks. These are used to build 3D anatomical models by reconstructing regions using the values of the voxels (density, attenuation, etc.).

CT and MRI scanners take numerous slices of an object's structure and save them in a standardized file format known as DICOM, which stands for Digital Imaging and Communications in Medicine. Each slice is composed of individual pixels recorded at specific locations, but when these slices are stacked together, they form an array of voxels in three dimensions. By analyzing the values associated with each voxel, which may indicate different tissues' properties (like hardness or softness), we can reconstruct a detailed 3D model of the anatomical structure, helping medical professionals visualize and understand complex bodily features.

Think of it as a loaf of bread made of many slices. Each slice is like a 2D image from a scan, and when you stack them, you can visualize the entire loaf. Just as the whole loaf presents the texture and characteristics of the bread, the stacked images create a 3D view of the patient's anatomy, making it easier to plan treatments or surgeries.

Applications: Patient-specific anatomical modelling, surgical planning, prosthetics, and 3D printed models for education/training.

Voxels play a crucial role in various medical applications. By utilizing the 3D models created from voxel data, healthcare professionals can tailor treatments for individual patients, aiding in surgical planning and design of prosthetics. 3D printing technology allows for creating physical models from voxel data, which can be used for educational purposes or to visualize complex anatomical structures in detail before performing surgery. This patient-specific approach enhances precision in medical procedures and improves education and training for upcoming healthcare providers.

Picture a surgeon using a detailed model of a patient's heart made from 3D printing. Just as an architect uses a model of a building to visualize and plan construction, surgeons use these voxel-based models to practice and refine their approaches before performing actual surgeries, improving outcomes and minimizing risks.

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