Allan MacLeod Cormack by Ana Patel

Individual Entry

anapatel01902 — 2024-02-07 16:48:13 UTC

Allan MacLeod Cormack was physicist from Johannesburg, South African who was awarded the Nobel Prize for developing the new diagnostic technique of computerized axial tomography (CAT) ⁽¹⁾.

During his part time position in a hospital’s radiology department, he became interested in the problem of x-ray imaging of soft tissues or layers of differing densities ⁽¹⁾.

Source (1): https://www.britannica.com/biography/Allan-MacLeod-Cormack

Cormack’s Background

anapatel01902 — 2024-02-07 16:54:10 UTC

During his residency in Cape Town’s Groote Schuur Hospital, Cormack witnessed the first surgery for a human heart transplant here⁽¹⁾.

He supervised the use of radioisotopes as the calibration of film badges that were used to monitor hospital workers’ exposure to radiation⁽¹⁾. He also witnessed the use of radiation for treatment of cancer which captured his attention⁽¹⁾.

Although Cormack had an interest in particle physics stemmed from his parent’s teaching and engineering background, his time at this hospital sparked his interest in learning about the flaws associated with imaging technology⁽¹⁾.

Source (1): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900806/

Paper Publishing his Experiments

anapatel01902 — 2024-02-07 17:23:35 UTC

Cormack began a series of experiments towards constructing a radiological cross-section which led him to write a paper in 1963 which was later published in the Journal of Applied Physics⁽¹⁾.

This paper set a foundational basis for CT scanning and revealed the potential of viewing cross sections of the body in vivo for the first time; however, the scientific community showed no interest in his work.⁽²⁾

Source (1): https://pubs.aip.org/aip/jap/article/34/9/2722/165376/Representation-of-a-Function-by-Its-Line-Integrals

Source (2): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900806/

Where the Experimentation Took Place

anapatel01902 — 2024-02-07 17:41:32 UTC

In 1966, Cormack moved to Tufts University in Boston as an assistant professor ⁽¹⁾. His work primarily focused on studying and teaching nuclear and particle physics, and conducted most of the research dedicated towards inventing the CT scan on his own time⁽¹⁾.

Later he went to Harvard to utilize their cyclotron, under his director Andreas Koehler, which helped him progress in his discovery of the CAT scan.

Source (1): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900806/#sec1-3title

Source (2): https://www.nobelprize.org/prizes/medicine/1979/cormack/biographical/

Continued Research by Sir Godfrey Hounsfield

anapatel01902 — 2024-02-15 05:27:33 UTC

Sir Godfrey Hounsfield was a biomedical engineer who had a keen interest in computer technology while working at EMI Central Laboratories as a on radar and guided weapons⁽¹⁾.

Afterwards, Hounsfield began to research and study various aspects of automatic pattern recognition and their potential in computed tomography⁽¹⁾. He came upon the theoretical mathematics from Cormack which helped him build the first clinical prototypes for a CAT scan⁽¹⁾.

Source (1): https://www.nobelprize.org/prizes/medicine/1979/hounsfield/biographical/

Cormack’s contributions

anapatel01902 — 2024-02-16 14:06:51 UTC

Cormack was the first to analyze the conditions necessary for obtaining accurate radiographic cross sections in biological systems⁽¹⁾. He understood that the problem was finding a mathematical model to accurately describe how x-rays penetrate in each part of a tissue slice⁽¹⁾.

His work focused on understanding how X-rays are absorbed by different parts of the tissue based on mean absorption value along straight lines within the sample⁽¹⁾.

Source (1): https://academic.oup.com/eurheartj/article/40/26/2101/5528774

Hounsfield’s Contributions

anapatel01902 — 2024-02-16 14:25:09 UTC

Hounsfield is known for introducing CT into medicine by constructing the first practicable system for medical care⁽¹⁾.

However, he was unaware of Cormack’s contributions so he developed his own method for reconstructing X-ray images⁽¹⁾. He initially designed four clinical prototypes, and in 1976 he progressed to five sophisticated prototypes that would eventually be used clinically.

Source(1): https://academic.oup.com/eurheartj/article/40/26/2101/5528774

The first CT scan

anapatel01902 — 2024-02-16 14:40:37 UTC

The first computer tomography (CT) was used for examine the skull and diseases of the brain⁽¹⁾. Due to its great precision and sensitivity, it allowed physicians to radiological diagnose neural diseases which led to a break breakthrough in this field.

While the process for the scan caused little discomfort to the patient, there was the drawback of radiation exposure and injection of radio contrast⁽¹⁾.

Source (1): https://academic.oup.com/eurheartj/article/40/26/2101/5528774

CT Scan Changes the Traditionally Methods for X-ray Systems

anapatel01902 — 2024-02-16 14:53:43 UTC

With the induction of CT into the medical field, there were a few changes to original x-ray systems. It replaced X ray film with sensitive crystal detectors as well as storing and analyzing the signals mathematically in the computer⁽¹⁾.

The computer was programmed to reconstruct an image of the examined cross section by solving a large number of equations including corresponding number of unknowns⁽¹⁾.

Began of the high sensitivity and precision, the device can detect very subtle differences in tissue density leading to very high density resolution⁽¹⁾.

Source (1): https://academic.oup.com/eurheartj/article/40/26/2101/5528774

Hounsfield worked independently from Cormack

anapatel01902 — 2024-02-18 16:45:54 UTC

Hounsfield was unaware of the work Cormack has already published in 1963⁽¹⁾. Therefore, he worked independently from Cormack and designed his own theoretical models for the CT scan.

Specifically, Hounsfield used automatic pattern recognition to describe a complete system of cross sectioning different parts of organ to reconstruct the image from a 3D to 2D dimension

Source (1): https://www.nobelprize.org/prizes/medicine/1979/hounsfield/biographical/

Inspiration for the Device

anapatel01902 — 2024-02-18 17:07:26 UTC

Cormack's time at the Groote Schuur Hospital sparked his interest in learning about the flaws associated with imaging technology⁽¹⁾.

While working as a trained nuclear physicist, he monitored the use of radioisotopes as the calibration of film badges that were used to track hospital workers’ exposure to radiation⁽¹⁾. He also witnessed the use of radiation for treatment of cancer which captured his attention⁽¹⁾.

Seeing these procedures, he became fascinated by imaging technology and its deficiencies. Cormack began a series of experiments towards constructing a radiological cross-sectional view of biological systems⁽¹⁾.

Source (1): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900806/

Contemporary Entry: Advancement in CT scanning

anapatel01902 — 2024-02-18 17:21:03 UTC

After Cormack’s and Hounsfield’s initial discovery of the CT scan, the advancement in the technology has progressed exponentially.

In the early 2000s, 64-sliced scanners were replacing the 16-sliced scanners in the 1960s⁽¹⁾. This allows scanning to occur about 4x faster than the original, which reduces the time and discomfort from the patient.

Additionally, recent research and scientists are exploring the use of artificial intelligence to help radiologist in image interpretation, automating routine tasks such as organ segmentation, tumor detection and anomaly identification⁽²⁾.

Source (1): https://www.neurologica.com/blog/advances-ct-scan-technology

Source (2):https://www.itnonline.com/article/advancements-computed-tomography-technology#:~:text=Portable%20and%20Point%2Dof%2Dcare,diagnostic%20imaging%20in%20critical%20situations.