Intraoperative Localisation of Impalpable Breast Lesions Utilising the ROLLIS Technique Following Peritumoral ^99mTc-colloid Sentinel Node Lymphoscintigraphy

Title:Intraoperative Localisation of Impalpable Breast Lesions Utilising the ROLLIS Technique Following Peritumoral ^99mTc-colloid Sentinel Node Lymphoscintigraphy

Volume: 10 Issue: 2

Author(s): Te-Jui Hung*, John Burrage, Anita Bourke and Donna Taylor

Affiliation:

• Department of Nuclear Medicine, Royal Perth Hospital, Perth,Australia

Keywords: Downscatter, I-125, Tc-99m, Peritumoral, Sentinel lymph node, lymphoscintigraphy.

Abstract: Background: Ultrasound or stereotactic guided hook-wire localisation has been the standard-of-care for the pre-surgical localisation of impalpable breast lesions, which account for approximately a third of all breast cancer. Radioguided occult lesion localisation using I-125 seeds (ROLLIS) is a relatively new technique for guiding surgical excision of impalpable breast lesions, and is a promising alternative to the traditional hook-wire method. When combined with Tc-99m labelled colloid for sentinel node mapping in clinically indicated cases, there has been uncertainty regarding whether the downscatter of Tc-99m into the I-125 energy spectrum could adversely affect the intra-operative detection of the I-125 seed, especially pertaining to a peritumoral injection.

Objective: To evaluate the percentage contribution of downscattered activity from Tc-99m into the I-125 energy spectrum in simulated intra-operative resections of an I-125 seed following different sentinel node injection techniques.

Method: Two scenarios were simulated using breast phantoms with lean chicken breast. The first scenario, with a 2cm distance between the Tc-99m injection site and the I-125 seed, simulated a periareolar ipsiquadrant injection with the subdermal or intradermal technique. The second scenario simulated a peritumoral injection technique with the Tc-99m bolus and an I-125 seed at the same site. Count rates were acquired with a hand-held gamma probe, and the percentage contribution of downscattered Tc-99m gamma photons to the I-125 energy window was calculated.

Results: In scenarios one and two, downscattered Tc-99m activity contributed 0.5% and 33% respectively to the detected count rate in the I-125 energy window. In both scenarios, the I-125 seed was successfully localised and removed using the gamma probe.

Conclusion: There is no significant contribution of downscattered activity associated with a peritumoral injection of Tc-99m to adversely affect the accurate intra-operative localisation of an I- 125 seed.

Cite this article as:

Hung Te-Jui *, Burrage John , Bourke Anita and Taylor Donna, Intraoperative Localisation of Impalpable Breast Lesions Utilising the ROLLIS Technique Following Peritumoral ^99mTc-colloid Sentinel Node Lymphoscintigraphy, Current Radiopharmaceuticals 2017; 10 (2) . https://dx.doi.org/10.2174/1874471010666170428113052

DOI https://dx.doi.org/10.2174/1874471010666170428113052	Print ISSN 1874-4710
Publisher Name Bentham Science Publisher	Online ISSN 1874-4729