Dopamine Pathway Imaging – Atlas of cases using TRODAT-1

Introduction: Dopamine pathway imaging has role in a variety of neurologic and psychiatric disorders, such as Parkinson’s disease (PD), attention-deficit/hyperactivity disorder (ADHD) and psychosis. Various positron emission tomography (PET) and single photon emission computed tomography (SPECT) based radiotracers are available for imaging the pre-synaptic dopaminergic pathway and post-synaptic dopamine receptors. The most commonly used radioligands are [¹²³I]FP-CIT, [¹⁸F]FDOPA, and [^99mTc]TRODAT-1. The primary clinical applications include distinguishing PD from non-neurodegenerative parkinsonian disorders and identifying Lewy Body Dementia versus Alzheimer’s disease.

Methods: Parkinson’s disease (PD) is the second most common neurodegenerative disease. It is associated with progressive loss of dopaminergic neurons in the substantia nigra and nerve terminals in the striatum. Dopamine transporter (DAT) is an integral plasma membrane protein present in the pre-synaptic terminal of dopaminergic neurons. [^99mTc]TRODAT-1 is a tropane derivative and an analogue of cocaine, which binds to the presynaptic DAT protein. This can guide a timely diagnosis and management of Parkinson’s disease, and can help improve patient quality of life significantly. In this exhibit, we wish to discuss interesting case findings of [^99mTc]TRODAT-1 SPECT/CT with the help of a series of cases of suspected PD.

Results: Pictorial demonstration of concepts of radiochemistry and imaging protocol of [^99mTc]TRODAT-1 scan will be provided along with functional imaging of cases with suspected PD. The key headings would include: Overview of Dopamine pathway imaging, Epidemiology of PD, Clinical cases utilizing [^99mTc]TRODAT-1 scan in cases of suspected PD and discussion of pertinent findings and pitfalls.

Conclusions: In this exhibit, we present case scenarios that help realise the potential of [^99mTc]TRODAT-1 SPECT/CT scan in cases of suspected PD.