Biopsy validation of 18F-DOPA PET and biodistribution in gliomas for neurosurgical planning and radiotherapy target delineation: results of a prospective pilot study.

Abstract

BACKGROUND:

Delineation of glioma extent for surgical or radiotherapy planning is routinely based on MRI. There is increasing awareness that contrast enhancement on T1-weighted images (T1-CE) may not reflect the entire extent of disease. The amino acid tracer (18)F-DOPA (3,4-dihydroxy-6-[18F] fluoro-l-phenylalanine) has a high tumor-to-background signal and high sensitivity for glioma imaging. This study compares (18)F-DOPA PET against conventional MRI for neurosurgical biopsy targeting, resection planning, and radiotherapy target volume delineation.

METHODS:

Conventional MR and (18)F-DOPA PET/CT images were acquired in 10 patients with suspected malignant brain tumors. One to 3 biopsy locations per patient were chosen in regions of concordant and discordant (18)F-DOPA uptake and MR contrast enhancement. Histopathology was reviewed on 23 biopsies. (18)F-DOPA PET was quantified using standardized uptake values (SUV) and tumor-to-normal hemispheric tissue (T/N) ratios.

RESULTS:

Pathologic review confirmed glioma in 22 of 23 biopsy specimens. Thirteen of 16 high-grade biopsy specimens were obtained from regions of elevated (18)F-DOPA uptake, while T1-CE was present in only 6 of those 16 samples. Optimal (18)F-DOPA PET thresholds corresponding to high-grade disease based on histopathology were calculated as T/N > 2.0. In every patient, (18)F-DOPA uptake regions with T/N > 2.0 extended beyond T1-CE up to a maximum of 3.5 cm. SUV was found to correlate with grade and cellularity.

CONCLUSIONS:

(18)F-DOPA PET SUV(max) may more accurately identify regions of higher-grade/higher-density disease in patients with astrocytomas and will have utility in guiding stereotactic biopsy selection. Using SUV-based thresholds to define high-grade portions of disease may be valuable in delineating radiotherapy boost volumes.

• Authors: Deanna H Pafundi, Nadia N Laack, Ryan S Youland, Ian F Parney, Val J Lowe, Caterina Giannini, Brad J Kemp, Michael P Grams, Jonathan M Morris, Jason M Hoover, Leland S Hu, Jann N Sarkaria, Debra H Brinkmann
• Journal: Neuro-oncology (Neuro Oncol) Vol. 15 Issue 8 Pg. 1058-67 (Aug 2013) ISSN: 1523-5866 [Electronic] England
• PMID: 23460322 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Radiopharmaceuticals
• fluorodopa F 18
• Dihydroxyphenylalanine

Topics

• Adult
• Aged
• Brain Neoplasms (diagnostic imaging, pathology, surgery)
• Dihydroxyphenylalanine (analogs & derivatives, pharmacokinetics)
• Female
• Follow-Up Studies
• Glioma (diagnostic imaging, pathology, surgery)
• Humans
• Immunoenzyme Techniques
• Male
• Middle Aged
• Neoplasm Grading
• Neurosurgical Procedures
• Pilot Projects
• Positron-Emission Tomography
• Prognosis
• Prospective Studies
• Radiopharmaceuticals (pharmacokinetics)
• Radiotherapy Planning, Computer-Assisted
• Radiotherapy, Image-Guided
• Surgery, Computer-Assisted
• Tissue Distribution
• Young Adult