Historadiography
Encyclopedia
Historadiography is a technique formerly utilized in the fields of histology
and cellular biology to provide semiquantitative information regarding the density of a tissue sample. It is usually synonymous with microradiography. This is achieved by layering a ground section of mineralized tissue (such as bone) with photographic emulsion on a glass slide and exposing the sample to a beam of X-rays. After developing the emulsion, the resulting radiograph can be viewed with a microscope
. A side-by-side comparison with a slide containing radiographs of various substances of known mass can provide a rough mass estimate, and therefore a rough approximation of the concentration of calcium salts in the sample.
Historadiography has also been used to visualize staining of tissue, such as spinal cord
samples with thorotrast
, which contains thorium
that is opaque to X-rays.
Over recent decades researchers have generally lost interest in historadiography. The most recent publication using the term (1998) to be indexed in PubMed
referred to autoradiography of tritium
incorporated in thymidine
.
Histology
Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...
and cellular biology to provide semiquantitative information regarding the density of a tissue sample. It is usually synonymous with microradiography. This is achieved by layering a ground section of mineralized tissue (such as bone) with photographic emulsion on a glass slide and exposing the sample to a beam of X-rays. After developing the emulsion, the resulting radiograph can be viewed with a microscope
Microscope
A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy...
. A side-by-side comparison with a slide containing radiographs of various substances of known mass can provide a rough mass estimate, and therefore a rough approximation of the concentration of calcium salts in the sample.
Historadiography has also been used to visualize staining of tissue, such as spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
samples with thorotrast
Thorotrast
Thorotrast is a suspension containing particles of the radioactive compound thorium dioxide, ThO2, used as a contrast medium in X-ray diagnostics in the 1930s and 40s ....
, which contains thorium
Thorium
Thorium is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder....
that is opaque to X-rays.
Over recent decades researchers have generally lost interest in historadiography. The most recent publication using the term (1998) to be indexed in PubMed
PubMed
PubMed is a free database accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez information retrieval system...
referred to autoradiography of tritium
Tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...
incorporated in thymidine
Thymidine
Thymidine is a chemical compound, more precisely a pyrimidine deoxynucleoside. Deoxythymidine is the DNA nucleoside T, which pairs with deoxyadenosine in double-stranded DNA...
.