Before a probe is selected, it is important to analyze the specific requirements for which the probe will be used. An optimal solution does not exist, because improvement of one characteristic will mean deterioration of one or more of the other characteristics.
Because uptake in lymph nodes may be low, a high sensitivity is the primary requirement. Collimation will increase the precision of localization of nodes before an incision is made. The side shielding of the probe should be excellent when a hot injection site is nearby. Collimation is recommended in this situation and the threshold setting must be raised to such a level that scattered radiation from the injection site is eliminated. Depending on the estimated radioactivity uptake, depth of the node, and the position of the injection site, the shield or collimator to be used is chosen. Optimally, the surgeon might want to be able to switch between different probe configurations during the surgical procedure, starting with excellent spatial resolution and (if necessary) energy discrimination, then switching to a higher sensitivity if needed.
Summarizing, a probe is required with high sensitivity, a choice of addon collimators, and the ability to suppress low-energy radiation at a level that can be specified by the user.
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Complete Guide to Preventing Skin Cancer. We all know enough to fear the name, just as we do the words tumor and malignant. But apart from that, most of us know very little at all about cancer, especially skin cancer in itself. If I were to ask you to tell me about skin cancer right now, what would you say? Apart from the fact that its a cancer on the skin, that is.