Single photon emission computed tomography-computed tomography visualization of sentinel lymph nodes for lymph flow guided nodal irradiation in oral tongue cancer.

PURPOSE: To evaluate correlation of single photon emission computed tomography-computed tomography (SPECT-CT) data on lymph flow (LF) from oral tongue cancer (OC) and the topography of lymph nodes (LN) metastases; to determine the clinical value of lymph flow guided radiotherapy (LFGRT). MATERIALS AND METHODS: SPECT-CT visualization of LF from the OC lesions was performed after peritumoral injection of 99mTc-phytate in 26 primary patients with clinical stage cT1-2N0M0 disease. We determined the individual drainage (unilateral/bilateral) from the tumor, and localization of sentinel LNs according to the neck levels. Metastases in LNs were verified with histology and a 2-year follow-up. RESULTS: SPECT-CT detected bilateral LF in 10 (38.5%) of 26 patients; in 16 (61.5%) cases the drainage was unilateral. Histology revealed LNs metastases in three cases; regional recurrences were diagnosed in other four patients. In all seven observations metastases were located at the same site and level as the sentinel LNs. In eight (30.8%) of 26 patients sentinel LNs were visualized unilaterally at levels Ib-IIa; in five cases, unilaterally at levels I-IIa-III. In these patients, LFGRT demonstrated 59%-70% reduction of irradiated volume, and 26%-42% and 51%-70% decrease of the mean dose to the spinal cord and the contralateral parotid gland. In patients with a bilateral drainage the reduction of doses absorbed by the spinal cord and contralateral parotid gland was 19% and 6%, respectively. CONCLUSION: Localization of sentinel LNs determined by SPECT-CT corresponds to the localization of metastatic LNs in terms of side and levels.

Atlas of sentinel lymph nodes in early breast cancer using single-photon emission computed tomography: implication for lymphatic contouring.

PURPOSE: to determine the localization of sentinel lymph nodes (SLNs) in a large cohort of patients with breast cancer and validate the European Society for Therapeutic Radiology and Oncology (ESTRO), Radiation Therapy Oncology Group (RTOG), and Radiotherapy Comparative Effectiveness (RADCOMP) guidelines on regional lymph node clinical target volume (CTV-LN) delineation. MATERIALS AND METHODS: A total of 254 women with cT1-3N0-1M0 breast cancer underwent single-photon emission computed tomography (SPECT-CT) visualization of SLNs after intra- and peritumoral injection of 99mTc-radiocolloids. All SPECT-CT images were fused with reference simulation computed tomography. A 3D atlas of SLNs was created and used for evaluation of CTV-LN defined by contouring guidelines. RESULTS: SPECT-CT visualized 532 SLNs that were localized in axillary level I in 67.5%, level II in 15.4%, level III in 7.3%, internal mammary in 8.5%, and supraclavicular in 1.3% cases. The majority of level II-IV and internal mammary SLNs were inside the recommended CTV-LN. Axillary level I SLNs were covered by ESTRO and RTOG contours in 85% and 85% cases, respectively. "Out of contours" SLNs were mostly detected in lateral subgroup of level I LN (18.5%), while 98%-99% of anterior pectoral and central axillary SLNs were covered by CTV-LN. Internal mammary SLNs were visualized in 33 cases and were outside ESTRO and RTOG contours in 3 and 6 observations, respectively. CONCLUSION: SPECT-CT atlas of SLNs demonstrated that in most cases ESTRO and RTOG guidelines correctly represented CTV-LNs with the exception of lateral subgroup of SLNs.

SPECT-CT visualization and biopsy of sentinel lymph nodes in patients with stage IAB-IIA cervical cancer.

OBJECTIVE: To evaluate the diagnostic accuracy of sentinel lymph node (SLN) biopsy and to determine clinical significance of preoperative single-photon emission computed tomography/computed tomography (SPECT-CT). METHODS: We retrospectively evaluate data and images of 55 women with stage IAB-IIA cervical cancer that underwent sentinel lymph node biopsy and subsequent lymph node dissection. 99mTc-phytate (300 MBq) was injected submucosally in 4 points and SPECT-CT started 2 h after the injection. All lymph nodes (LN) that accumulated radiocolloids were regarded as sentinel. Next day after the mapping radical hysterectomy with complete pelvic and parametrial LN dissection and SLN biopsy were performed according to the institute protocol. RESULTS: SPECT-CT identified SLNs in 51 of 55 patients. All SLNs were successfully detected during the surgery. The SLN mapping efficacy was 92.7%. LN metastases were diagnosed in 6/51 (11.8%) cases, including 2 patients with positive SLNs. Sensitivity, negative predictive value (NPV) and false-negative rate for SLN biopsy were as follows: 33.4%, 91.8% and 66.6%. In patients with unilateral SPECT-CT localization of SLNs, LN metastases were identified in 4 (20%) of 20 patients but SLN biopsy was false negative in all cases. In 31 women, SPECT-CT detected SLNs on both sides of the pelvis. In this group, regional LN metastases were diagnosed in 2 patients, and in both cases metastases were detected only in SLNs. CONCLUSIONS: In women with SPECT-CT visualization of SLNs on both sides of the pelvis, SLN biopsy had high sensitivity and NPV. In patients with unilateral SLN localization, SLN biopsy cannot be used for the prediction of regional LN status.

Lymph flow guided irradiation of regional lymph nodes in patients with cervical cancer: Preliminary analysis of scintigraphic data.

PURPOSE: To evaluate patterns of lymph flow from primary lesions in patients with cervical cancer and to determine how useful for radiotherapy planning this information can be. MATERIALS AND METHODS: SPECT-CT visualization of sentinel (SLN) lymph nodes (LNs) was performed in 36 primary patients with IB-IIB cervical cancer. The acquisition started 120-240 min after 4 peritumoral injections of 99mTc-radiocolloids (150-300 MBq in 0.4-1 ml). We determined localization of LN with uptake of radiocolloids, type of lymph flow (mono-, bi-lateral) and lymph flow patterns (supraureteral paracervical, infraureteral paracervical and directly to para-aortic LNs). RESULTS: SLNs were visualized in 31 of 36 women. Bilateral lymph-flow was detected in 22 (71%), monolateral - in the other 9 (29%) cases. The distribution of SLNs was as follows: external iliac - 64.5%, internal iliac - 54.8%, obturator - 32.2%, common iliac - 35.5% and pre-sacral 3.2%. Para-aortic LNs were visualized in 5 (16.1%) patients. The supraureteral paracervical pattern of lymph flow was identified in 22, infraureteral paracervical - in 4 and their combination - in the other 5 women. CONCLUSION: Visualization of an individual pattern of lymph flow from primary cervical cancer can be considered as a promising tool for optimization of the volume of irradiated regional LNs.

Axillary lymph node staging in breast cancer: clinical value of single photon emission computed tomography-computed tomography (SPECT-CT) with 99mTc-methoxyisobutylisonitrile.

OBJECTIVE: To determine diagnostic accuracy of SPECT, CT and SPECT-CT in axillary lymph node (LN) staging in breast cancer (BC). METHODS: Sixty consecutive patients with primary operable T1-3NxM0 BC were included in this study. All patients underwent SPECT-CT examination on Symbia-T16 scanner which consists of dual-head gamma camera combined with 16 slices diagnostic CT. SPECT-CT acquisition started 10-15 min after i/v injection of 740-1,000 MBq of 99mTc-MIBI. On CT images of axillary LN we analyzed following diagnostic signs: size (short axis more or less than 10 mm), shape (round or oval), cortical thickness and fat content (solid or with fat gate). Intensity of tracer uptake in axillary LN was classified as follows: grade (Gr) I-background, Gr II-slightly above background, Gr III-intense but below uptake in muscles, Gr IV-as high as in muscles. Histological examination of dissected LN was used as gold standard. RESULTS: Various combinations of CT signs of axillary LN involvement demonstrated moderate diagnostic value with best results characterized by low (55 %) sensitivity (SEN), 97 % specificity (SP) and 83 % accuracy (AC). Intensive (Gr IV) uptake of 99mTc-MIBI in axillary LN characterized by low (55 %) SEN, high (100 %) SP and moderate (84 %) AC. Combination of CT and SPECT signs looks most promising especially when LN metastases were diagnosed in patients with enlarged solid LN or normal sized LN with Gr III-IV 99Tc-MIBI uptake. In these cases, SEN was equal to 75 %, SP-90 %, AC-85 %, only one of 5 patients with false negative results had metastases in more than 2 LN. CONCLUSIONS: By combination of SPECT and CT data we can more accurately diagnose axillary LN invasion by breast cancer.