To describe the types of radiotracers used in positron emission tomography (PET) and single-photon emission computed tomography (SPECT) in detecting skeletal metastases.
To provide an overview of mechanism of uptake, physical properties, advantages and limitations of the radiotracers, and how they can be applied inclinical practice.
Bones are common sites of metastases in most cancers. Skeletal metastasis is often a poor prognostic indicator and presents late when devastating complications such as fractures and spinal cord compression occur. Other significant complications include pain, hypercalcemia and bone marrow suppression. Therefore, it is important to detect skeletal involvement early and to determine whether patients respond to treatment.
Traditional bone scintigraphy and cross-sectional imaging are useful but are limited in their sensitivity and specificity at detecting bone metastases and at monitoring treatment response. It can...
Findings and procedure details
Bone-specific SPECT tracer:
Bone-specific and non-specific PET tracers:
68Ga-PSMA and 18F-PSMA
Advantages of SPECT and SPECT-CT(Figure 1)
Similar to planar scintigraphy, SPECT utilises gamma-ray, both these modalities are highly sensitive, widely available and relatively cheap to conduct. Compared to planar scintigraphy which has poor spatial resolution (1 cm), SPECT-CT is able to more accurately localise metabolically active foci and characterise them, reducing equivocal reports and allows reliable identification of degenerative disease, often difficult to be distinguished from bone...
With the advancement in nuclear medicine, there is greater potential of improving diagnostic accuracies in detecting osseous metastasis. Having an understanding of the physical properties, advantages and limitations of the radiotracers is important to optimise the clinical applications of SPECT and PET. However, results from comparative studies can be difficult to translate into clinical practice and rigorous cost-effectiveness analysis is required to justify application in clinical practice.
Personal information and conflict of interest
O. Y. Wong; London/UK - nothing to disclose
V. Naidu; London/UK - nothing to disclose
G. Kakar; London/UK - nothing to disclose
H. Steinitz; London/UK - nothing to disclose
J. Bomanji; London/UK - nothing to disclose
G. Gnanasegaran; London/UK - nothing to disclose
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