Daghighian F, Mazziotta J C, Hoffman E J, Shenderov P, Eshaghian B, Siegel S, Phelps M E
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Med Phys. 1994 Jan;21(1):153-7. doi: 10.1118/1.597240.
An intraoperative beta probe was designed, built, and tested for detection of radio-labeled malignant tissues that has the advantage of being selectively sensitive to beta while insensitive to gamma radiation. Since beta radiation (electrons or positrons) has a short range in tissue, this probe is ideal for detecting tracers in tumors at the surface of the surgical field. This probe contains a plastic scintillation detector sensitive to beta rays and to a lesser degree some background gamma rays. A second detector counts spurious gamma rays and allows for their subtraction from the activity measured by the first detector. Sensitivity of the dual probe for I-131 and F-18 was measured to be 108 counts/s/kBq (4000 counts/s/microCi). The dual-detector probe faithfully measured the 10:1 "tumor" to background ratio of radioactivity concentrations in a simulated environment of a tumor in the presence of intense background 511 keV photons. In another phantom experiment, simulating abdominal tumor deposits with various realistic I-131 radioactive concentrations, the probe was able to accurately identify tumors of approximately 50 mg with a tumor/normal radioactivity concentration of 3/1 in 10 s.
设计、制造并测试了一种术中β探测器，用于检测放射性标记的恶性组织，该探测器具有对β射线选择性敏感而对γ射线不敏感的优点。由于β辐射（电子或正电子）在组织中的射程较短，这种探测器非常适合检测手术视野表面肿瘤中的示踪剂。该探测器包含一个对β射线敏感且对一定程度的背景γ射线也敏感的塑料闪烁探测器。第二个探测器对杂散γ射线进行计数，并允许从第一个探测器测量的活度中减去这些γ射线。测量该双探测器对I-131和F-18的灵敏度为108计数/秒/千贝克勒尔（4000计数/秒/微居里）。在存在高强度背景511keV光子的肿瘤模拟环境中，双探测器探头忠实地测量了放射性浓度10:1的“肿瘤”与背景比。在另一个体模实验中，模拟具有各种实际I-131放射性浓度的腹部肿瘤沉积物，该探头能够在10秒内准确识别出肿瘤/正常放射性浓度为3/1、重量约为50mg的肿瘤。
