Sunday, June 30, 2024

Nuclear Medicine; Pioneers

Nuclear Medicine is the field that combines principles of chemistry, physics biology and medicine to develop diagnostic and therapeutic techniques with the use of a radioactive substance.  Several pioneers have contributed to the field:

Marie Currie (1861-1934) discovered the radioactive elements plutonium and radium.  Her work led to the use of radioactivity in medicine.

George de Hevesy (1885-1966) he suggested and developed the tracer principle, using radioactive isotopes to study chemical processes in living organisms. He won the Nobel Price in Chemistry in 1943 for his work on radioactive tracers.

Earnst Lawrence ( 1901-1958) he invented the cyclotron, a particle accelerator which was used to produce radioactive tracers in nuclear medicine 

Benedict Cassen (1902-1972) he developed the rectilinear scanner in 1950s, the first imaging device for nuclear medicine that preceded the gamma camera. 

Hal Anger (1920-2005) he invented the gamma camera (also known as Anger camera) in 1957.  The Anger camera is the key imaging device used in nuclear medicine today to detect radiation emitted by radioactive tracers in the body.

Michael Phelps, Edward Hoffman and Michael Ter-Pogossian are credited with the development of the modern PET scanner. Michael Phelps in particular is credited for his work in creating the first practical PET scanner in the mid-1970s.  The collective efforts of these researchers led to the establishment of PET as a powerful medical imaging technique.

The above mentioned pioneers, among others have contributed in the establishment and advancement of nuclear medicine, making it an important field in modern diagnostics and treatment. 

This post is dedicated to John Olsen who was the Chief of Nuclear Medicine during my tenure as Department Chairman at Ohio State University and Lyda Gogou the Dean of Health Sciences at West Attica University who was among the PET pioneers in Greece.

Saturday, June 1, 2024

Breast imaging: newer developments

 Mammography is a medical imaging study that uses low dose x-rays to examine the human breast.  It can detect tumors before they are felt on physical examinationand can find microcalcifications that may indicate breast cancer.  Recently digital imaging has replaced film/screen mammography as it provides better image quality and allows easier storage and image sharing. Three dimensional mammography known as tomosynthesis is a newer mamographic technique which is useful in women with dense breast parenchyma.  Multiple randomized studies have demonstrated decreases in mortality from breast cancer by approximately 30% when screening mammograms are performed annually in women whose age is between 40 to 70. 

In 1990, Jackson in a Radiology article suggested ultrasound as a valuable tool in breast imaging especially when a mass is felt clinically or detected on mammography. Ultrasound helps in differentiating between solid masses that can be cancerous and fluid filled cysts that are benign.  In cases when a cancer is suspected ultrasound is used to guide needle biopsies and other therapeutic procedures such as breast cancer ablation. While useful, ultrasound is not a replacement for mammography.  For women with dense breasts when combined with mammography and clinical examination they provide a comprehensive evaluation.

In 1976, Frank, Ferris et al in a NEJM article described the technique of needle localization that allows placement of a wire with its tip adjacent to the lesion.  The technique ensures tat the surgeon can remove the suspicious finding with minimal tissue removal.  Wire localization can be performed either under mammographic or ultrasound guidance.

Magnetic resonance imaging (MRI) is using a magnetic field and radio waves to create detailed images of the breast.  Research in breast MRI started in 1980 in the USA and Germany.  MRI is highly sensitive and can detect abnormalities not seeing in either mammography or ultrasound.  In 1986, Heywang et al demonstrated that breast cancers enhance following gadolinium administration. In 1990, Kuhl et al published their study in the use of MRI in the screening of women at high risk for breast cancer, such as those with strong family history or genetic mutations like BRCA1 or BRCA2.

This post is dedicated to my friend and associate John Olsen MD who introduced the concept of mobile mammography and was the first who did stereotactic biopsies at Ohio State University.  He was the chief of Nuclear Medicine and Breast imaging at OSU and President of our departmental corporation URI.  I had the pleasure working with him during my tenure at OSU and learning from him on how to allay cancer patients fears.