Assessment of response of brain metastases to radiotherapy by PET imaging of apoptosis with ¹⁸F-ML-10.
OBJECTIVE
Early assessment of tumor response to therapy is vital for treatment optimization for the individual cancer patient. Induction of apoptosis is an early and nearly universal effect of anticancer therapies. The purpose of this study was to assess the performance of (18)F-ML-10, a novel PET radiotracer for apoptosis, as a tool for the early detection of response of brain metastases to whole-brain radiation therapy (WBRT).


METHODS
Ten patients with brain metastases treated with WBRT at 30 Gy in ten daily fractions were enrolled in this trial. Each patient underwent two (18)F-ML-10 PET scans, one prior to the radiation therapy (baseline scan), and the second after nine or ten fractions of radiotherapy (follow-up scan). MRI was performed at 6-8 weeks following completion of the radiation therapy. Early treatment-induced changes in tumor (18)F-ML-10 uptake on the PET scan were measured by voxel-based analysis, and were then evaluated by correlation analysis as predictors of the extent of later changes in tumor anatomical dimensions as seen on MRI scans 6-8 weeks after completion of therapy.


RESULTS
In all ten patients, all brain lesions were detected by both MRI and the (18)F-ML-10 PET scan. A highly significant correlation was found between early changes on the (18)F-ML-10 scan and later changes in tumor anatomical dimensions (r = 0.9).


CONCLUSIONS
These results support the potential of (18)F-ML-10 PET as a novel tool for the early detection of response of brain metastases to WBRT.
Department of Radiation Oncology, Nuclear Medicine, Radiology and Neurology, Rabin Medical Center, Petach-Tikvah, Israel. Aarona2@clalit.org.il
Aaron M
AM
Allen
Miri
M
Ben-Ami
Ayelet
A
Reshef
Adam
A
Steinmetz
Yulia
Y
Kundel
Edna
E
Inbar
Ruth
R
Djaldetti
Tal
T
Davidson
Eyal
E
Fenig
Ilan
I
Ziv
D000328:Adult; D000368:Aged; D017209:Apoptosis; D001692:Biological Transport; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008764:Methylmalonic Acid / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000378:metabolism; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000009:adverse effects / Q000379:methods*; D011849:Radioactive Tracers; D012449:Safety; D059629:Signal-To-Noise Ratio; D016896:Treatment Outcome
C532430:5-fluoropentyl-2-methylmalonic acid; D011849:Radioactive Tracers; D008764:Methylmalonic Acid