Introducing the GammaPen: All-in-One Gamma Probe for Sentinel Lymph Node Biopsy

Aram  Radnia; Hamed  Abdollahzadeh; Behnoosh  Teimourian; Mohammad Hossein  Farahani; Mohammad Reza   Ay

doi:10.18502/fbt.v8i2.6519

Aram Radnia Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
Hamed Abdollahzadeh Parto Negar Persia Co., Tehran, Iran
Behnoosh Teimourian Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
Mohammad Hossein Farahani Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
Mohammad Reza Ay Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/fbt.v8i2.6519

Keywords: Gamma Probe; Sentinel Lymph Node; Performance Evaluation.

Abstract

Purpose: Using an itra-operative gamma probe after injection of radiotracer during surgery helps the surgeon to identify the sentinel lymph node of regional metastasis through the detection of radiation. This work reports the design and specification of an integrated gamma probe (GammaPen), developed by our company.

Materials and Methods: GammaPen is a compact and fully integrated gamma probe. The detector module consists of a thallium-activated Cesium Iodide (CsI (Tl)) scintillator, and a Silicon Photo Multiplier (SiPM), shielded using Tungsten housing. Probe sensitivity, spatial resolution and angular resolution in air and water, and side and back shielding effectiveness were measured to evaluate the performance of the probe based on NEMA NU3 standard.

Results: The sensitivity of the probe in the air/water at distances of 10, 30, and 50 mm is 18784/176800, 3500/3050, and 1575/1104 cps/MBq. The spatial and angular resolutions in the air/scattering medium are 40/47 mm and 77/87 degrees at a 30 mm distance from the probe. The detector shielding effectiveness and leakage sensitivity are 99.91% and 0.09%, respectively.

Conclusion: The results and surgeon experience in the operating room showed that GammaPen can be effectively used for sentinel lymph node localization.