TY - JOUR T1 - Performance of a Dual, Solid-State Intraoperative Probe System with <sup>18</sup>F, <sup>99m</sup>Tc, and <sup>111</sup>In JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 352 LP - 360 VL - 42 IS - 2 AU - Raymond R. Raylman Y1 - 2001/02/01 UR - http://jnm.snmjournals.org/content/42/2/352.abstract N2 - The use of tracer-avid radiopharmaceuticals and handheld, intraoperative, radiation-sensitive probes to localize areas of tumors promises to improve surgical treatments of cancer. Currently several β- and γ-ray-emitting radiopharmaceuticals are proposed for use in these procedures. Therefore, intraoperative-probe systems should be capable of optimum performance with several different radionuclides. The goal of this study was to evaluate the performance of a dual, solid-state probe with three of these radionuclides (18F, 99mTc, and 111In). Methods: The detector unit of the intraoperative-probe system used in this investigation consisted of a stack of two ion-implanted silicon detectors separated by 0.5 mm. The system could be operated in two modes: β optimized, in which the difference between the signals from the two detectors was calculated to correct the β signal for photon contamination, and photon-optimized mode, in which the signals were summed. Detection sensitivity and an index measuring β detection selectivity were measured in both acquisition modes with the three different radionuclides. The γ-ray detection sensitivity of a commercially available probe was measured with 99mTc and compared with the results with a solid-state probe. Results: β and photon emissions (γ-rays and annihilation photons) produced by all three radionuclides were detected by the probe. In β-optimized acquisition mode, the greatest β-detection sensitivity was achieved with 18F; photon sensitivity was greatest for measurements with 111In. The lowest detection sensitivities (β and photon) were obtained with 99mTc. With the probe system in γ-optimized mode, the greatest β and photon sensitivities were achieved with 18F; the lowest were obtained with 99mTc. The γ-detection sensitivity measured with 99mTc in γ mode (5.59 ± 0.41 counts per second [cps]/kBq) compared surprisingly well with the results from the commercial probe (8.75 ± 0.47cps/kBq). Conclusion: The results from this investigation demonstrate the flexibility and versatility of the dual, solid-state probe system used in this study. These capabilities may be used to improve existing techniques or lead to new methods for performing radionuclide-guided surgeries. ER -