Introduction

The radioguided occult lesion localization (ROLL) technique has been used in breast conservative surgery by associating lumpectomy and sentinel lymph node biopsy.
The combination of two techniques is commonly known as SNOLL - Sentinel lymph node and occult lesion localization.

Radioguided localization of occult breast lesion

Extensive use of mammography has increased the identification of DCIS and LCIS.
Such lesions must be well located preoperatively, completely removed avoiding unnecessary traumas in the surrounding tissues and carefully centered in the specimen excised.

For the localization of opacities and microcalcification observed by mammography device equipped with a computerised stereotactice system is used for guiding the injection once teh 3D coordinates of the lesion have been calculated.
Craniocaudal projections are acquiredd for lesions located in the superior and inferior breast quadrants, and external and internal lateral projections are obtained for lesions in the lateral and medial quadrants.
A 22 guage needle in the stereotactic frame is inserted in the lesion with position of the needle tip corresponding to the calculated coordinates.
New mammogram is obtained to verify the location of the tip of the needle.
Injection of the 99mTc MAA is given followed by immediate administration of 0.2ml of radioopaque contrast medium.
Remove Needle.
Take another image to verify that the contrast medium has been properly located in the lesion.

When the occult lesion is displated by ultrasound, the radiotracer is injected under ultrasonographic guidance.
Examination id done using a liner probe at a frequency of 10 to 13 or 7.5 to 10MHz, depending on breast size.
Then another probe (7.5 to 10MHz) is cinnected to a needle biopsy device.
The needle is introduced in the device and manually inserted in the center of the breast lesion.
The radiotracer is then injected followed by 0.2ml of saline.

Later, Scintigraphic images are acquired for 5 to 10 minutes with 512 x 512 matrix and zoom of 1.3 in order to exclude external radioactive contamination.
If the area of administration of the radiotracer is a clear cut spot, patient can undergo excisional biopsy.
When the radiotracer has diffused over a large area of breast, localization should be replicated by an alternative method.

Surgery can be performed on the same or on the following day.
The gamma probe is introduced by a small skin incision.
Intraoperative localization of the injection site of 99mTc MAA by gamma probe permits early identification and removal of the breast lesion.
The specimen is counted ex-vivo by the gamma probe to confirm complete removal of the lesion. It could also be radiographed to verify the success of the procedure.

Follow me on Twitter @KoteRutuja for more updates and resources.