Assessing good operating conditions for intraoperative imaging of melanoma sentinel nodes by a portable gamma camera. Issue 1 (February 2015)

• Record Type: Journal Article
• Authors: Riccardi, Lucia; Gabusi, Michele; Bignotto, Michele; Gregianin, Michele; Vecchiato, Antonella; Paiusco, Marta
• Is Part Of: Physica medica. Volume 31:Issue 1(2015)
• Page Start: 92
• Page End: 97
• Publication Date: 2015-02
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2014.10.079
• Languages: English
• ISSNs: 1120-1797

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Abstract</title> <sec> <title id="sectitle0015">Objective</title> <p id="abspara0010">To provide guidance for reliable identification of low-activity sentinel nodes in the setting of melanoma surgery using a commercial hand-held gamma camera.</p> </sec> <sec> <title id="sectitle0020">Methods</title> <p id="abspara0015">The average uptake of <sup>99m</sup>Tc nanocolloid by sentinel nodes was evaluated in 95 excised nodes using a Sentinella 102<sup>®</sup> (Oncovision, Valencia, Spain) portable gamma camera. The device sensitivity was assessed for different source depths and collimator distances, imaging an 8-mm sphere filled with a known-activity solution of <sup>99m</sup>Tc. Five nuclear medicine physicians were asked to identify the source at different activity levels and positions within the field of view. For each image the number of signal counts inside a circular region of interest (ROI) was measured, while the variability of ROI counts among operators was assessed. The number of counts providing a minimal, near-constant inter-operator variability was determined as a criterion for a consistent identification of the source. Either the minimum activity or the acquisition time needed to collect the appropriate statistics were then calculated.</p> </sec> <sec> <title id="sectitle0025">Results</title> <p id="abspara0020">The median SN uptake (0.5%) turned out to be compatible with values reported in the literature. The sensitivity of the compact gamma camera ranged from ∼25 cpm/kBq to ∼1 cpm/kBq. A total of 50 counts in the ROI circumscribing the lymph node-simulating sphere appeared to be a robust criterion for identification of the source.</p> </sec> <sec> <title id="sectitle0030">Conclusions</title> <p id="abspara0025">Ten megabecquerels of injected activity at the time of surgery and one minute of acquisition allows reliable identification of sentinel nodes for collimator-to-source distances up to 10 cm.</p> </sec> </abstract>