Nuclear imaging is a vital component of the range of medical imaging services available, and one that provides a variety of specific benefits, both in terms of patient experience and recovery, as well as from a clinical perspective. We spoke with Dr Philip Monaghan (FRACP, FAANMS), of Southern Medical Imaging Services, about the application of this particular branch of medical imaging, and how it can offer early diagnosis, proper treatment and optimal patient outcomes.
Dr Monaghan is Positron Emission Tomography (PET) certified following training at St Thomas’ Hospital, London and Westmead Hospital in Sydney. Dr Monaghan holds fellowships in the Royal Australasian College of Physicians, the Australasian Association of Nuclear Medicine Specialists and the American Society of Nuclear Cardiology. He is a member of the Australian Medical Association, the Australia and New Zealand Society of Nuclear Medicine, the American Society of Nuclear Medicine, the British Society of Nuclear Medicine and the European Association of Nuclear Medicine.
Nuclear medicine is an imaging process where a small amount of radioactive material is injected into the patient. After a waiting period (usually between two and four hours), a device scans the body.
According to the Mayo Clinic, the radiation dose that the patient receives is usually less than a routine chest X-ray.
Dr Monaghan explained that “the nuclear medicine bone scan can be performed on any part of the body, obviously depending on the clinical indication. There are no exclusions to the procedure, meaning a nuclear medicine examination can be safely performed in people with contrast sensitivity or allergies, reduced renal function or metallic implants such as pacemaker devices.”
The scan is often performed after an initial clinical assessment, whether that be following an appointment with a traditional health care provider, such as a GP, or after initial treatment upon admission after a trauma injury. “A whole-body bone scan should be performed once the initial clinical assessment and emergency X-rays have been undertaken,” explained Dr Monaghan. “It provides a better whole-body assessment to more completely diagnose injuries sustained.”
However, specialists are more likely to order this type of imaging procedure than General Practitioners because of “higher levels of training and experience in the usefulness of nuclear medicine. The GP may not understand the value and earlier use of bone scans,” Dr Monaghan explained.
It is commonly used in cases of acute injury or previous workplace injury “for assessment of suspected injuries that have been missed. They are also used where a whole-body examination is required to assess for suspected multiple injuries, such as after a motor vehicle accident or severe industrial injury.” The advantage is that “a whole-body image is nearly always completed,” offering a better overall picture for the treating physician.
“The metabolic activity of bone becomes active very soon after an injury or other bony pathology becomes active. Nuclear medicine bone scans become abnormal in many circumstances before there are radiographically demonstrated alterations to the bony structure. It is well-known that bone scans can be positive before plain x-rays or CT scans following an injury. In the case of active arthritis, the bone scan may become positive several years before radiographic changes become apparent.
“Due to the performance of a whole-body examination, bony injury in unsuspected or undetected sites can be clearly visualised and thus used as a screening tool to assess for other or remote sites of injury. Commonly a bone scan can indicate an injury in an anatomical site missed by X-ray, CT or MRI examination because these studies are usually performed on an isolated region only.”
Dr Monaghan emphasised that the technology cost “is comparable to an MRI or CT, but those options only examine one area. In contrast, nuclear medicine offers an assessment of the whole skeleton” – making it a more cost-effective option in terms of total body parts imaged.
In the context of improving recovery timeframes, reducing time off work and improving return-to-work rates, Dr Monaghan explained that in patients who have suspected skeletal pathology such as an acute injury – which has not been evident on a plain X-ray, CT scan and sometimes an MRI that has not been extensive enough – the nuclear imaging has provided a positive result. “The most regularly missed sites of an acute fracture include the hand and wrist, thoracic and lumbar spine, ribs, sternum, scapulae, sacrum, coccyx, pelvis as well as in the ankle and foot. It is a regular occurrence for the bone scan to be positive when a plain x-ray or CT scan is equivocal or unable to demonstrate a recent fracture.”
Recent coverage in medical journals has indicated both the usefulness of the procedure, but also its application in cases specific to the lower back and arthritic conditions, where it has shown to be particularly useful in diagnosing painful, ongoing conditions where other forms of medical imaging have been negative.
Dr Monaghan explained that “bone scanning of the spine (neck, dorsal and lumbar spine) can demonstrate the site of progressive degenerative change accurately and or facet/sacroiliac joint injury or arthritis.
“Accurate localisation of the active pathology is helpful to the referring surgeon to guide treatment to the right site and plan appropriate intervention.
“In my experience, most neurosurgeons or orthopaedic surgeons require complementary information from MRI, and nuclear medicine bone scans to best determine the level and type of pathology that they are dealing with.”
While there are no limitations to the type of patients who can receive this type of medical imaging procedure, according to Dr Monaghan, Australia has “great regional variation in availability. This is due to the cost of practice establishment, and the small number of dedicated nuclear medicine physicians able to write reports.” He estimates that the total number of nuclear medicine trained doctors available for reporting sits at around 300.
In addition to limited availability in some regional areas, Dr Monaghan explained that there is “significant variation amongst general practitioners as to the usefulness and benefits of nuclear medicine. Many general practitioners have a good understanding of the technology. However, I am always surprised at the number of “good” general practitioners who have a poor understanding of what the technology may offer in the management of their patients.”
“Nuclear medicine offers earlier diagnosis, which leads to more effective and accurate treatment,” he explained. “It should also be noted that a negative bone scan has an extremely high negative predictive value for the exclusion of recent bony trauma or injury.”
When we queried the potential risks of the procedure, Dr Monaghan explained that “routine bone scanning has been performed for approximately 50 years in Australia safely, accurately and cost-effectively.”
“The radiation dose and whole-body exposure from a routine nuclear medicine examination are very low and roughly equivalent to the dose received from a CT scan from one region in the body (either skull, chest or abdomen).
“Multiple nuclear medicine procedures can be safely performed and are commonly performed following diagnosis to assess treatment effect and or complication.”
Dr Monaghan also believes that there will be advances in the camera systems and supplementary hardware and software systems that will improve the technology moving forward.
Dr Monaghan’s clinic, Southern Nuclear Imaging Group, has locations in the Illawarra, Canterbury and Blacktown areas and provides comprehensive nuclear imaging services.
Do you have a question about nuclear imaging? We will be conducting further question and answer opportunities with Dr Monaghan and provide the results in our next newsletter.