The researchers are currently trying to produce gold nanoparticles in different shapes and sizes, to label them with other radiocolloids
, and to study tissue distribution of the labeled nanoparticles.
Radiocolloids (technetium 99m sulfur colloid or technetium 99m colloidal albumin), filtered or unfiltered, can also be used; the optimal particle size is 10 to 15 nm.
The radiocolloid is injected around the tumor in the nuclear medicine suite from 30 minutes to 24 hours before surgery.
Radiocolloid has also been discussed as assisting in the SLN biopsy of colon carcinomas.
In oral cancers, the SLN may be close to the primary tumor in the oral cavity and difficult to identify in a level I dissection; the radiocolloid produces a "shine-through" effect, with an increasing background signal from the primary tumor.
Some believe that preoperative treatment may impair the flow of the radiocolloid or the blue dye.