A mobile high-resolution gamma camera for therapeutic dose control during radionuclide therapy

Area of Science:

• Nuclear Medicine
• Medical Imaging
• Radiotherapy Physics

Background:

• Molecular radiotherapy using iodine-131 (¹³¹I) is a primary treatment for thyroid diseases.
• Significant patient variability in therapeutic doses and treatment effects necessitates individualized dosimetry.
• Accurate quantitative assessment of ¹³¹I distribution and biokinetics is crucial for optimizing clinical outcomes.

Purpose of the Study:

• To develop a high-resolution, mobile gamma camera for bedside quantitative assessment of ¹³¹I.
• To evaluate the imaging performance and quantification capabilities of the prototype camera.
• To validate the camera's utility for individualized dosimetry in thyroid disease treatment.

Main Methods:

• Developed a prototype mobile gamma camera with a 5 × 5 cm² field of view, featuring a 3D-printed tungsten collimator and a CeBr₃ scintillator with silicon photomultiplier detectors.
• Evaluated intrinsic and overall imaging performance using ¹³³Ba and ¹³¹I sources.
• Tested quantification accuracy with ¹³¹I-filled thyroid phantoms using single and conjugate view approaches, with and without scatter correction.

Main Results:

• The camera demonstrated high imaging performance: 7.68 ± 0.01% energy resolution, 0.74 ± 0.28 mm intrinsic spatial resolution, and 0.15 ± 0.10 mm spatial distortion.
• Overall spatial resolution was 3.14 ± 0.03 mm at 5 cm with a sensitivity of 1.23 ± 0.01 cps/MBq.
• Activity recovery factors exceeding 97% were achieved with thyroid phantoms, indicating excellent quantification accuracy.

Conclusions:

• The developed mobile gamma camera shows significant promise for accurate ¹³¹I quantification at the patient's bedside.
• Preliminary results support its potential as a tool for individualized dosimetry in molecular radiotherapy for thyroid diseases.
• Further development is motivated towards a clinical-grade camera with enhanced imaging capabilities and a larger field of view.