Sentinel Node Images

FIgure 15. A) Sentinel node imaging showing 1 mintue sequential frames after intradermal injection of 99mTc-sulfur colloid. The sentinel node is seen as a small focus of activity at about 2 o'clock superior to the injection site. B) Summed view of the sequential images. The injections site has been shielded and there is improved visualization of the sentinel node (arrow).

regional nodal basin is typical of melanoma, with less than 1% of patients presenting with "skip" lesions. The histological evaluation of the sentinel node, therefore, is an important prognostic indicator and one which directs appropriate wide field dissection. Five year survival in patients with tumor negative sentinel lymph nodes is 90% following selective dissection and 93% following complete lymph node dissection. Surgical intervention therefore can, with confidence, be limited in patients with negative sentinel lymph nodes.

Imaging after peritumoral intradermal injection usually shows the lymphatic channels within 20 minutes of administration and the sentinel node(s) should be seen by 30 minutes (Fig. 15). Whilst one nodal basin is usually seen for lesions on the limbs, up to three geographically disparate nodal basins may be demonstrated after injection around a melanoma site on the trunk or head and neck region and up to 40% of patients will show unexpected drainage patterns. A skin marker is placed over the node(s) and the patient moved to the operating room for sentinel node excision. A hand held gamma probe is an important adjunct to the localization of the marked node at surgery.

In this population of patients, sentinel node imaging has been shown to be effective in identifying the sentinel nodes in 90-95% of patients in most series and should now be regarded as standard of care in the management of this rapidly expanding patient group.

FDG Imaging

Most authors believe that PET imaging with FDG is the most effective way of identifying locoregional and distant metastases. PET imaging methods show a sensitivity and specificity of over 90% in patients with medium to high pre-test probabilities. Tumor deposits as small as 5 mm have consistently been identified, and sensitivity is significantly higher than for either CT or MRI. However, because of high background activity in the liver and brain, small lesions in these sites will be more effectively diagnosed with morphological imaging techniques. False positive

How To Prevent Skin Cancer

How To Prevent Skin Cancer

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.

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