Nuclear Medicine

History

Radioisotopes have been used in Medicine routinely since the 1950's, and allowed organ function and pathology to be determined non-invasively. The Royal Adelaide Hospital's use of such techniques dates back to this time, and formally began in 1962.

The Department of Nuclear Medicine was established, as part of the Institute of Medical & Veterinary Science, in a purpose built area on 1 May 1968  by amalgamating diagnostic radioisotope services from :

• the Royal Adelaide Hospital's Radiotherapy Department
• the Institute of Medical & Veterinary Science
• the University of Adelaide's Departments of Medicine and Surgery
• utilising the resources of the University of Adelaide's Anti-Cancer Foundation Radiation Physics Unit

The initial staff of 14 people included Director Dr Harry Lander and a staff of Medical, Chemistry & Physics graduates who operated Gamma cameras, static probes, the Whole Body Monitor and provided Radiopharmacy services.

Clinical research programs in areas such as cardiovascular, brain function, gastric emptying and pharmaceutical development have always been part of the department's philosophy. These areas continue today.

In 1977 the department helped establish ultrasound services on the hospital campus in conjunction with the Radiology department.

Computer analysis of data at the University of Adelaide became possible in 1968, with further upgrades in 1978 to two Nuclear Medicine systems in house.

The department became part of the Royal Adelaide Hospital in 1983. This also saw the department's first investigations into bone mineral analysis by supporting a research bone densitometer, and examining calcium turnover with the whole body monitor.

The department has progressively updated cameras and bone densitometry equipment over this time, including :

• installation of single photon emmission tomographic (SPECT) gamma cameras in 1987 and 1991
• the addition of a dual headed SPECT gamma camera in 1995
• the first whole body bone densitometer in Australia in 1987
• the first mobile X-ray based bone densitometry service in Australia in 1994
• the first near radiographic image X-ray densitometer in Australia in 1994
• updating bone densitometers to ensure the same calibration is used on both city and rural instruments
• major departmental renovations in 2001 (and ongoing) with dedicate suites for Positron Emmission Tomography (PET), Bone Densitometry, Nuclear Medicine Imaging and Haematological studies
• development of urea breath testing kits and testing services for Australia wide distribution in 1995
• installation of the first Positron Emission Tomography suite in South Australia in 2000, with an upgrade to PET with integral CT for image fusion in 2005
• a common analysis platform for Nuclear Medicine computer images
• electronic distribution of doctors reports in 2004
• acceptance of electronic referrals for doctors within the hospital in 2004
• electronic storage and distribution of images to be complete in 2005

How it works

Nuclear Medicine uses radioisotopes to study body functions in health and disease. The result is often an image which portrays both the function and anatomy of organs.
More conventional imaging, such as radiology, depends more on the anatomy of the body.
Three important bases for Nuclear Medicine follow:

Radiopharmaceuticals
The radioisotopes used in Nuclear Medicine are usually short lived (the isotope half life is usually measured in hours), and in combination with a radiopharmaceutical to which the radioisotope is attached, remain radioactive in the body for very short times.
To determine how an organ is functioning, the radioisotope (frequently ^99mTechnetium - a man made radioisotope) is attached to a pharmaceutical compound which is metabolised by a specific organ such as the heart, bones or liver. In a normal organ, the uptake of this radiopharmaceutical will have characteristic uptake, clearance or distribution. Organs which are not functioning normally will have variations on these characteristics, and therefore indicate potential disease.

Gamma Cameras
We can observe these properties in the organ with a gamma camera - an instrument designed to detect gamma rays. The detection of the gamma ray results in an electrical signal being produced by the camera, which will also indicate its position.
Often, the data produced over a period of time (seconds or minutes) will be collected to generate movies of the organ functioning - like a heart beating.
The gamma ray emmissions of the target organ (with the radiopharmaceutical) can therefore produce 2 dimensional images on film or digitally. With the addition of a rotating gantry, the image can be become 3 dimensional - tomography.

Image processing
Nuclear Medicine is a major user of computers. As the gamma camera data is electronic, a digital interface is used on a computer to store both spatial and time information. This can generate large amounts of data, which can be analysed with the computers to produce filling and emptying curves, time to peak, differences information, and much more complex analysis. Additionally, manipulation of the images can be performed to present diagnostic information in the most appropriate way.