Lymphoscintigraphy

Indications:

1. Assessment of patients with suspected lymphoedema.

2. Identification of sentinel lymph node (SLN)

Principle:

• Small radiolabelled colloidal particles are injected into lymphatic rich epidermal areas. The particles are small enough to move freely in lymph vessels and are temporarily trapped in nodes.

• In cases of suspected lymphoedema the nano-colloid is injected into the web spaces of the hands or feet.
  When the procedure is used to identify the sentinel node; in breast carcinoma, the nano-colloid is injected in the periareolar region and in melanoma, it is injected either side of the melanoma scar.

Preparation and Procedure:

• The length of the procedure, (1–3 hours) should be noted when organising a patient's theatre schedule. If the patient has early morning surgery, the procedure should be arranged for the afternoon before.

• Images are taken until the SLN is visualised. The position of the sentinel node is then marked on the skin.

Comments:

• The SLN is the first node that drains from a tumour. If the node is biopsied and found to be tumour free, then the likelihood of nodal spread of tumour is very low. The SLN is identified in the operating theatre using a specially designed radiation probe and a blue dye.

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