Publications by authors named "Aleksi R Schrey"

3 Publications

  • Page 1 of 1

Evaluation of repeated [(18)F]EF5 PET/CT scans and tumor growth rate in experimental head and neck carcinomas.

EJNMMI Res 2014 16;4:65. Epub 2014 Dec 16.

Turku PET Centre, Medicity Research Laboratory, University of Turku, Tykistökatu 6A, Turku, FI-20520, Finland ; Department of Oncology and Radiotherapy, Turku University Hospital, Turku, FI-20521, Finland.

Background: Tumor hypoxia is linked to invasion and metastasis but whether this associates with tumor growth rate is not well understood. We aimed to study the relationship between hypoxia evaluated with the positron emission tomography (PET) tracer [(18)F]EF5 and tumor growth. Our second goal was to assess the variability in the uptake of [(18)F]EF5 in tumor between two scans.

Methods: Four human head and neck squamous cell carcinoma (UT-SCC) cell lines were xenografted in flank or neck of nude mice, and tumor size was closely monitored over the study period. The tumors were clearly visible when the first [(18)F]EF5 scan was acquired. After an exponential growth phase, the tumors were imaged again with [(18)F]EF5 and also with (18)F-fluorodeoxyglucose ([(18)F]FDG).

Results: There was a clear correlation between the percentage of tumor growth rate per day and the [(18)F]EF5 uptake in the latter scan (r = 0.766, p = 0.01). The uptake of [(18)F]EF5 in the first scan and the uptake of [(18)F]FDG did not significantly correlate with the tumor growth rate. We also observed considerable variations in the uptake of [(18)F]EF5 between the two scans.

Conclusions: The uptake of [(18)F]EF5 in the late phase of exponential tumor growth is associated with the tumor growth rate in mice bearing HNC xenografts.
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May 2015

Monitoring microvascular free flaps with tissue oxygen measurement and PET.

Eur Arch Otorhinolaryngol 2008 Jul 30;265 Suppl 1:S105-13. Epub 2008 Jan 30.

Department of Otorhinolaryngology-Head and Neck Surgery, Turku University Central Hospital, 20521 Turku, Finland.

Tissue oxygen measurement and positron emission tomography (PET) were evaluated as methods for predicting ischemia in microvascular free flaps of the head and neck. Ten patients with head and neck squamous cell cancer underwent resection of the tumour followed by microvascular reconstruction with a free flap. Tissue oxygenation of the flap (P(ti)O(2)) was continuously monitored for three postoperative (POP) days and the blood flow of the flap was assessed using oxygen-15 labelled water and PET. In three free flaps a perfusion problem was suspected due to a remarkable drop in P(ti)O(2)-values, due to two anastomosis problems and due to POP turgor. No flap losses occurred. During the blood flow measurements with PET [mean 8.5 mL 100 g(-1) min(-1 )(SD 2.5)], the mean P(ti)O(2) of the flaps [46.8 mmHg (SD 17.0)] appeared to correlate with each other in each patient (p<0.05, n=10). Tissue oxygenation measurement is a feasible monitoring system of free flaps. The perfusion-study with PET correlates with P(ti)O(2)-measurement.
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July 2008

Functional evaluation of microvascular free flaps with positron emission tomography.

J Plast Reconstr Aesthet Surg 2006 ;59(2):158-65

Department of Otorhinolaryngology, Head and Neck Surgery, Turku University Central Hospital, FIN-20521 Turku, Finland.

Background: The aim of this study was to assess blood flow (BF) of microvascular free flaps studied with positron emission tomography (PET) in patients with head and neck squamous cell cancer (HNSCC) undergoing major radical surgery 3-4 weeks after high-dose radiotherapy.

Methods: Five patients underwent resection of the HNSCC of the oral cavity followed by microvascular reconstruction with a radial forearm flap. Regional BF in oral and neck tissues was measured with PET using radiolabelled water ([15O]H2O) twice (1-2 and 12-14 days, respectively) following radical surgery.

Results: In the first postoperative PET study, the median BF in the cutaneous flap area was 5.1 mL/100 g/min, and in the muscle contra-lateral to the recipient site 19.9 mL/100 g/min. A low flap-to-muscle BF ratio appeared to correlate with circulatory incongruity, and thus with poorer flap success. The follow-up study on the second postoperative week supported the results of the primary PET scan.

Conclusions: This pilot study suggests that PET using [15O]H2O is a feasible method to quantitatively evaluate BF of the whole free flap in patients operated on for oral
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June 2006