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Brigitte Wilczek

Publications and source records attributed to Brigitte Wilczek.

5 recordsLinked to original sources
PubMed2006

Different methods for the detection of small changes in uptake between single-photon emission computed tomography (SPECT) examinations: 99mTc-sestamibi in chemotherapy for breast tumours.

AIM: This study was undertaken to evaluate different methods for the detection of small changes in uptake between single-photon emission computed tomography (SPECT) examinations in the same individual. No standard exists for making digital evaluations at single-photon examinations. For this purpose, we employed a patient cohort from a previous study assessing the response to neoadjuvant chemotherapy for breast cancer using Tc-hexakis-2-methoxyisobutylisonitrile (Tc-sestamibi). METHODS: The tumour uptake in 29 women with locally advanced breast cancer was examined using Tc-sestamibi and SPECT before neoadjuvant chemotherapy and, on average, 19 days after one chemotherapy cycle. The histology of the finally resected tumour confirmed a therapeutic response. Different assessments of the uptake, various levels of background activity subtraction and different reference tissues for relative activity calculations were used. The tumour uptake and activity of the reference tissues were also related to the administered activity. RESULTS: Different definitions of tumour activity had little influence. Relating the tumour uptake to a large portion of the abdomen, as well as visual evaluation, showed a therapeutic response. Comparison with the administered activity showed that the apparent responses were due to an increased activity of the reference tissues. Referring the tumour uptake to the administered activity truly depicted a therapeutic response. CONCLUSIONS: A critical attitude is necessary when making digital evaluations at SPECT. Digital data may seem more relevant than they really are. Relative comparisons may be unreliable. It may be necessary to develop standardized methods for this purpose.

Adult↗
PubMed2006

Integrin receptor imaging of breast cancer: a proof-of-concept study to evaluate 99mTc-NC100692.

UNLABELLED: The present study was a proof-of-concept study to provide an initial indication of the efficacy and safety of imaging malignant breast tumors using (99m)Tc-NC100692. The agent is a small peptide with high affinity for integrin receptors that are upregulated and expressed preferentially on proliferating endothelial cells. METHODS: Sixteen patients with suggestive mammographic findings and 4 patients with benign lesions were included. The "standard of truth" was based on the histopathologic diagnosis of the recruited patients. All subjects received up to 75 microg of (99m)Tc-NC100692 with an average (99m)Tc activity of 694 MBq (range, 561-747 MBq). Safety endpoints were treatment-emergent adverse events (AEs) and changes in a limited physical examination, electrocardiogram (ECG) recordings, blood biochemistry, hematology, coagulation, vital signs, and urine analysis after administration of (99m)Tc-NC100692 and throughout the 24-h follow-up. Static images and SPECT were acquired between 40 min and 2.5 h after injection of the agent. Two experienced nuclear medicine physicians read the images in a nonblinded fashion. RESULTS: Nineteen of 22 malignant lesions were detected using (99m)Tc-NC100692 scintigraphy. Twenty lesions confirmed as malignant by histopathology were seen on mammography or ultrasound. Two additional lesions were identified from histopathology alone. Safety parameters evaluated through the follow-up period of 2.5 h included clinical laboratory tests, vital signs, and ECG. Five of 20 subjects experienced nonserious AEs, and all AEs were classified as mild. One subject experienced an AE (dysgeusia) possibly related to administration of (99m)Tc-NC100692. This AE was mild and lasted only for a few minutes. No deaths, serious AEs, or withdrawals due to AEs occurred during the study. CONCLUSION: Nineteen of 22 malignant lesions (86%) were clearly detected via scintigraphic imaging after administration of (99m)Tc-NC100692. Overall, the efficacy data in subjects with suspected breast lesions suggest that (99m)Tc-NC100692 scintigraphy may be effective in detecting malignant lesions. The use of (99m)Tc-NC100692 in subjects with breast cancer is safe and well tolerated. Further studies are warranted to assess the clinical potential of (99m)Tc-NC100692.

Adult↗
PubMed2004

Sentinel node scintigraphy in breast cancer using a dual tracer technique.

AIM: In order to depict the anatomy and improve the localization, sentinel node scintigraphy in breast cancer was combined with intravenous administration of pertechnetate. As this may reduce the detectability of weak 'hot spots', the number of lymph nodes detected at scintigraphy and at surgery in one group of patients was compared with that obtained in another group that had not received pertechnetate. PATIENTS AND METHODS: The number of 'hot spots' at frontal and lateral views in 47 female patients at scintigraphy performed 2-3 h after subcutaneous injection of radiocolloid together with 25 MBq pertechnetate i.v. was compared in retrospect with that of 41 female patients who had not received pertechnetate. The number of lymph nodes detected at surgery using a hand-held gamma probe together with blue dye in the two groups was also compared. The washout kinetics of pertechnetate was studied in 10 patients. RESULTS: There was no difference in the number of detected lymph nodes at any comparison. The kinetics study revealed a decreasing activity with time after correction for physical decay. CONCLUSION: Administration of a 25 MBq pertechnetate i.v. in order to improve the anatomical localization at sentinel node scintigraphy in breast cancer does not reduce the detectability of radioactive lymph nodes.

Adult↗
PubMed2004

99mTc-exametazime as a breast tumor-seeking agent: comparison with 99mTc-sestamibi.

UNLABELLED: (99m)Tc-sestamibi is commonly used for mammoscintigraphy. Occasional uptake of (99m)Tc-exametazime in various tumors has been described. In this study, an intraindividual comparison of these 2 radiopharmaceuticals for mammoscintigraphy was made. METHODS: A kinetic study (30 min) in the lateral prone view of 20 breast tumors (> or =1 cm) in 20 women was conducted with (99m)Tc-exametazime. Thereafter, 21 breast tumors (> or =1 cm) in 21 women were examined with both agents (2 patients were included in both groups) under identical conditions (interval, 2-7 d). In the latter group, the tumor-to-background breast activity ratio and the tumor uptake normalized to the administered activity (cps/MBq) at 10 min after injection were calculated and compared for both agents. RESULTS: All tumors (43 tumors in 39 patients) were visualized with (99m)Tc-exametazime. There was also one instance of false-positive uptake using this agent. The uptake phase lasted approximately 10 min. Thereafter, the activity was practically stable. (99m)Tc-Sestamibi failed to depict 4 tumors. On the group level, the tracers did not differ in tumor-to-background activity ratio or normalized tumor uptake. Intraindividual agreement in tumor-to-background ratios between the tracers was moderate (intraclass correlation coefficient = 0.49). CONCLUSION: Uptake of (99m)Tc-exametazime in breast tumors > or = 1 cm seems to be comparable with that of (99m)Tc-sestamibi at a group level. The specificity is unknown. There is a restricted intraindividual agreement between the tracers, confirming different uptake mechanisms. This may open up possibilities for assessing different tumor characteristics in vivo, especially since the uptake of both agents is based on mechanisms believed to be involved in resistance to antineoplastic drugs.

Breast Neoplasms↗