[Development of a front shield for a 3D positron emission tomograph]

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Biophysics

Background:

• Three-dimensional (3D) Positron Emission Tomography (PET) acquisition exhibits higher accidental coincidence rates and scatter coincidence rates compared to 2D acquisition.
• The absence of a slice shield collimator in 3D PET contributes to increased count loss.
• Reducing gamma rays from outside the axial field of view (FOV) is hypothesized to improve 3D PET image quality.

Purpose of the Study:

• To develop and evaluate a front shield for a Shimadzu SET-2300W (Headtome V) PET camera.
• To mitigate gamma ray penetration from outside the axial FOV during brain studies.
• To assess the impact of the front shield on coincidence rates, count loss, and overall image quality in 3D PET.

Main Methods:

• Development and implementation of a novel front shield for the Shimadzu SET-2300W (Headtome V) PET camera.
• Testing the efficacy of the front shield in reducing external gamma rays during 3D PET acquisition for brain imaging.
• Quantification of accidental coincidence rates, scatter coincidence rates, and count loss under various conditions with and without the front shield.

Main Results:

• The developed front shield effectively decreased gamma ray incidence from outside the FOV.
• A significant reduction in the accidental coincidence rate was observed with the front shield.
• Count loss at high count rates was also diminished, indicating improved data acquisition efficiency.

Conclusions:

• The front shield is a viable method for enhancing 3D PET image quality by reducing external gamma ray interference.
• Implementing this front shield can lead to improved accuracy and reliability in clinical brain studies using 3D PET.
• Further research may explore the application of similar shielding techniques in other PET imaging scenarios.