Chapter 75 - Micro-CT and volumetric imaging in developmental toxicology

Abstract

The chapter briefly introduces the modern bioimaging technologies and their uniqueness when used in DART studies, with emphasis on X-ray micro-CT and volumetric imaging technology, especially for applications in developmental toxicology. These bioimaging technologies include various light microscopies, X-ray radiography and fluoroscopy, computed tomography (CT or CAT), magnetic resonance imaging (MRI), positron emission tomography (PET), scintigraphy, single photon emission computed tomography (SPECT), thermography and ultrasound imaging. With the successful application of modern imaging technologies in the clinical domain, especially tomography imaging approaches such as CT, MRI and ultrasound imaging, scientists immediately began to think about applying these imaging technologies to preclinical toxicology studies. However, the most popular animal species used in preclinical studies are small animals. The basic principles of X-ray computed tomography is Planar X-ray imaging i.e. conventional radiography, produces two-dimensional (2D) projection images of three-dimensional (3D) objects. The CT principles can be defined in three parts: X-ray projection imaging, computer-assisted imaging and image reconstruction. The contrast agent staining process plays a critical role in micro-CT imaging of soft tissue. The alizarin red-S-based single-staining method and alizarin red-S with alcian blue-based double-staining methods are two techniques for the bone and cartilage examination. Ultrasound imaging (UI) is a primary fetal imaging technology in the clinical setting. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are two additional volumetric imaging modalities that have high molecular imaging sensitivity.