What is the difference between pet and spect

Through this technique, it is able to determine whether or not a patient has any cardiovascular disease. It can ideally be performed when the patient is at rest or during a nuclear stress test. The procedure also includes a Perfusion imaging which is generally done once at rest and the second time after cardiac stress. The radiotracer used has a half-life of six hours, giving plenty of time for the technologists to perform the imaging. The decay of the radiotracer combines into thousands of gamma-ray which results in forming an appropriate image suitable for diagnosis.

Recently, a PET probe was approved by the FDA to aid in the accurate diagnosis of Alzheimer's disease, which previously could be diagnosed with accuracy only after a patient's death. In the absence of this PET imaging test, Alzheimer's disease can be difficult to distinguish from vascular dementia or other forms of dementia that affect older people.

The total radiation dose conferred to patients by the majority of radiopharmaceuticals used in diagnostic nuclear medicine studies is no more than what is conferred during routine chest x-rays or CT exams. There are legitimate concerns about possible cancer induction even by low levels of radiation exposure from cumulative medical imaging examinations, but this risk is accepted to be quite small in contrast to the expected benefit derived from a medically needed diagnostic imaging study.

Like radiologists, nuclear medicine physicians are strongly committed to keeping radiation exposure to patients as low as possible, giving the least amount of radiotracer needed to provide a diagnostically useful examination. Research in nuclear medicine involves developing new radio tracers as well as technologies that will help physicians produce clearer pictures.

A bacterial infection is a common complication of implanting a medical device into the body. With more patients receiving device implants than ever before, infections from implants are a growing problem. Currently, these types of infections are diagnosed based on physical exam results and microbial cultures. However, such techniques are only useful for detecting late stage infections, which usually have already become difficult to treat. Conversely, medical devices may be needlessly removed when doctors mistake inflammation that is a normal consequence of surgery with inflammation due to an infection.

NIBIB is currently supporting research to develop a new family of PET imaging contrast agents that are taken up specifically by bacterial cells, but not human cells. Hyperactivity disorder is a good example. We know that it is probably caused by a lack of dopamine and that it can be treated - at least sometimes - with dopaminergic medication. Their function in the human brain as a whole is only marginally known, because it is difficult to research. So, correlative imaging means that one tries to establish a relationship between different imaging data.

In the case of the brain, PET and SPECT are usually combined with MRI but, on the other hand, this is usually done retrospectively - retrospective fusion - because presently hybrid cameras combining those modalities are not available. We initiated a research project with Professor Hornegger at the Technical Faculty, which aims at developing intelligent fusion algorithms. The problem is that we have to deal with the different positions of a patient in the different camera systems. This is done by non-rigid transformations, but calculating them correctly is a major problem.

This is comparative imaging with the objective to match - to generate an image of a patient that has three-dimensional features that are matched with each other. How does metabolic process X function in that region? Or metabolic process Y? That is the objective of correlative imaging.

Due to its widespread use, there are more trained technologists available too. The longer half-life of the SPECT radiotracer makes it more widely available and is ideal for cardiac stress testing. Improvements in radiotracer and camera technology are expected to boost image quality, helping to overcome a common SPECT complaint.

It is reported that SPECT resolution is at 12mm to 15mm and images can be prone to attenuation on older cameras. SPECT also does not provide a quantifiable estimate of the blood flow.

PET is less widely available and much more costly to implement, with cameras running into the millions of dollars. Cardiac stress testing can be performed with existing radiopharmaceuticals but can be challenging due to their short half-life, although this is potentially going to be solved in the future as new radiotracers are being developed.

One of the biggest pluses for PET scanning is the superiority of its image quality. PET provides high spatial resolution and the capability to provide quantitative estimates of blood flow. Each has its own strengths and challenges, but each can provide quality images that allow for accurate diagnosis.

Is one better than the other?