TY  - JOUR
U1  - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1  - Lim, Winna
A1  - Acker, Gueliz
A1  - Hardt, Juliane
A1  - Kufeld, Markus
A1  - Kluge, Anne
A1  - Brenner, Winfried
A1  - Conti, Alfredo
A1  - Budach, Volker
A1  - Vajkoczy, Peter
A1  - Senger, Carolin
A1  - Prasad, Vikas
T1  - Dynamic 18F-FET PET/CT to differentiate recurrent primary brain tumor and brain metastases from radiation necrosis after single-session robotic radiosurgery
JF  - Cancer Treatment and Research Communications
N2  - Objective
Cyberknife robotic radiosurgery (RRS) provides single-session high-dose radiotherapy of brain tumors with a steep dose gradient and precise real-time image-guided motion correction. Although RRS appears to cause more radiation necrosis (RN), the radiometabolic changes after RRS have not been fully clarified. 18F-FET-PET/CT is used to differentiate recurrent tumor (RT) from RN after radiosurgery when MRI findings are indecisive. We explored the usefulness of dynamic parameters derived from 18F-FET PET in differentiating RT from RN after Cyberknife treatment in a single-center study population.

Methods
We retrospectively identified brain tumor patients with static and dynamic 18F-FET-PET/CT for suspected RN after Cyberknife. Static (tumor-to-background ratio) and dynamic PET parameters (time-activity curve, time-to-peak) were quantified. Analyses were performed for all lesions taken together (TOTAL) and for brain metastases only (METS). Diagnostic accuracy of PET parameters (using mean tumor-to-background ratio >1.95 and time-to-peak of 20 min for RT as cut-offs) and their respective improvement of diagnostic probability were analyzed.

Results
Fourteen patients with 28 brain tumors were included in quantitative analysis. Time-activity curves alone provided the highest sensitivities (TOTAL: 95%, METS: 100%) at the cost of specificity (TOTAL: 50%, METS: 57%). Combined mean tumor-to-background ratio and time-activity curve had the highest specificities (TOTAL: 63%, METS: 71%) and led to the highest increase in diagnosis probability of up to 16% p. – versus 5% p. when only static parameters were used.

Conclusions
This preliminary study shows that combined dynamic and static 18F-FET PET/CT parameters can be used in differentiating RT from RN after RRS.
KW  - Radiation necrosis
KW  - Robotic radiosurgery
KW  - Cyberknife
KW  - 18F-FET-PET/CT
KW  - Dynamic 18F-FET-PET/CT
KW  - Amino acid PET
Y1  - 2022
UN  - https://nbn-resolving.org/urn:nbn:de:bsz:960-opus4-24347
SN  - 2468-2942
SS  - 2468-2942
U6  - https://doi.org/10.25968/opus-2434
DO  - https://doi.org/10.25968/opus-2434
VL  - 32
ER  -