||Early clinical experience utilizing scintillator with optical fiber (SOF) detector in clinical boron neutron capture therapy: its issues and solutions
Ishikawa, Masayori ,
Yamamoto, Tetsuya ,
Matsumura, Akira ,
Hiratsuka, Junichi ,
Miyatake, Shin-Ichi ,
Kato, Itsuro ,
Sakurai, Yoshinori ,
Kumada, Hiroaki ,
Shrestha, Shubhechha JOno, Koji
2016-12 , BioMed Central
Background: Real-time measurement of thermal neutrons in the tumor region is essential for proper evaluation of
the absorbed dose in boron neutron capture therapy (BNCT) treatment. The gold wire activation method has been
routinely used to measure the neutron flux distribution in BNCT irradiation, but a real-time measurement using gold
wire is not possible. To overcome this issue, the scintillator with optical fiber (SOF) detector has been developed.
The purpose of this study is to demonstrate the feasibility of the SOF detector as a real-time thermal neutron
monitor in clinical BNCT treatment and also to report issues in the use of SOF detectors in clinical practice and their
Material and methods: Clinical measurements using the SOF detector were carried out in 16 BNCT clinical trial
patients from December 2002 until end of 2006 at the Japanese Atomic Energy Agency (JAEA) and Kyoto University
Research Reactor Institute (KURRI).
Results: The SOF detector worked effectively as a real-time thermal neutron monitor. The neutron fluence obtained
by the gold wire activation method was found to differ from that obtained by the SOF detector. The neutron
fluence obtained by the SOF detector was in better agreement with the expected fluence than with gold wire
activation. The estimation error for the SOF detector was small in comparison to the gold wire measurement. In
addition, real-time monitoring suggested that the neutron flux distribution and intensity at the region of interest
(ROI) may vary due to the reactor condition, patient motion and dislocation of the SOF detector.
Conclusion: Clinical measurements using the SOF detector to measure thermal neutron flux during BNCT
confirmed that SOF detectors are effective as a real-time thermal neutron monitor. To minimize the estimation error
due to the displacement of the SOF probe during treatment, a loop-type SOF probe was developed.