^99m Tc-phytate lymphoscintigraphy for detection of sentinel node: Preliminary results of the first year′s clinical experience in Isfahan, Iran

Abstract

Sentinel lymph node is the first regional lymph node that drains the lymph from the primary tumor. It is potentially the first node to receive the seeding of lymph-borne metastatic cells. This study aimed to discuss lymphoscintigraphy procedural guidelines for detection of sentinel node using 99mTc-Phytate in Isfahan, Iran. Moreover, the preliminary results of the first year's clinical experience of lymphoscintigraphy in Isfahan, Iran are also presented. A total of 36 consecutive sentinel node procedures were performed following our protocol in March 2013 to March 2014. For all 36 patients, after intradermal injection of 0.5–1 mCi of 99mTc-Phytate, 5, 30 and 120 min with hands up lymphoscintigraphy was performed. All procedures were performed in a 1-day setting with 99mTc-Phytate injection in intradermal volume of about 0.1 cc. At 5, 30 and 120 min after injection, anterior and lateral images (4 min), were acquired using gamma-camera (energy 140 keV, window 15–20% and LEHR collimator). For all patients, at least one axillary sentinel lymph node was detected. For three patients, 2 SNs were seen. The images 5 min after injection showed at least one axillary sentinel node in 18 of 36 patients. However for the remaining patients, more delayed images (after 30 and 120 min) were needed. Although, no changes were seen in 120 min images compared to 30 min images. Considering the used protocol, from the evaluated data it can be concluded that lymphoscintigraphy after 30 min periareolar injection of about 0.5–1 mCi 99mTc-Phytate in an intradermal volume of about 0.1 cc yields an axillary sentinel node in all the patients. Imaging 120 min after injection is of no additional value and can be omitted.

Optimal imaging time for Tc-99m phytate lymphoscintigraphy for sentinel lymph node mapping in patients with breast cancer

“…Most SLNs in patients who did not demonstrate SLNs on imaging were eventually identified intraoperatively either by blue dye or a hand-held gamma detector. Studies directly comparing Tc-99m phytate with other colloid radiotracers also showed noninferiority of Tc-99m phytate in terms of the imaging and the intraoperative nodal detection rate, which supports our study findings [21222324]. Although the use of Tc-99m phytate is largely restricted in certain Asian countries, current evidence suggests that it is quite adequate for SLN mapping and should suffice in hospitals performing breast cancer surgery.…”

“…The injection dose, nonetheless, is reasonably regarded as a predictive variable because higher injected radioactivity theoretically produces a more intense signal from the SLN and hence is easier to detect by a gamma camera. Although most studies used a radioactivity dose <1.0 mCi, our study results imply that a 2.0 mCi total radioactivity dose might achieve a better detection rate when Tc-99m phytate is used [142223242526]. This phenomenon can be endorsed by the hypothesis we propose.…”

Determination of Uterus Absorbed Dose by Patients following Myocardial Perfusion Scan using TLD and Conjugate View Methods

“…The radiation dose estimation is the basis for the use of radiopharmaceuticals in nuclear medicine, and it is also the first step in protection against radiation. For example, in therapeutic applications of radiopharmaceuticals, it is necessary to assess the absorbed dose in the tumor and normal tissues to choose the most appropriate treatment protocol, maintaining doses to vital organs at safe levels [1].…”