A new silicon detector for microdosimetry applications in proton therapy

Abstract

A silicon-on-insulator diode array with a sensitive depth of 10 microns has been developed for microdosimetry in proton therapy. The detector was coupled to a radiation-hard charge sensitive amplifier with the probe assembly capable of measuring an LET down to 1.2 keV/ym. The device has been successfully tested at two proton therapy centers: The 230 MeV Northeastern Proton Therapy Center, Boston and the 250 MeV Proton Medical Research Center at Tsukuba, Japan. The device offers much improved spatial resolution compared with a proportional gas counter particularly in the critical high dose region around the proton Bragg peak. Due to its small cross-sectional area (0.04 cm2) measurements may also be made in facilities with short high intensity beams.

A computational technique for simulating ionization energy deposition by energetic ions in complex targets

“…As previously reported [2], [3], [5], the SOI microdosimeter consists of an array of reversed biased, p-n junctions as illustrated in Figs. 1 and 2.…”

“…As previously reported [2], a radiation hard hybrid AMPTEK A-250 preamplifier was connected to the SOI chip in close proximity. The electronic readout circuit was optimized to reduce electronic noise and hence enable the measurement of low LET events in the microdosimeter.…”

“…There are however several disadvantages in measuring lineal energy spectra with TEPC's [1]. A number of these have been overcome by using reversed biased, silicon-on-insulator diode arrays with microscopic sensitive volumes as microdosimeters [2]- [5]. Silicon microdosimetry studies using SOI devices in radiation oncology have been reported previously [2]- [5].…”

“…A number of these have been overcome by using reversed biased, silicon-on-insulator diode arrays with microscopic sensitive volumes as microdosimeters [2]- [5]. Silicon microdosimetry studies using SOI devices in radiation oncology have been reported previously [2]- [5]. In these studies, silicon microdosimeters were used to measure lineal energy spectra in such radiation oncology modalities as boron-neutron capture therapy (BNCT) [3], [4] and Proton therapy [2].…”

“…Silicon microdosimetry studies using SOI devices in radiation oncology have been reported previously [2]- [5]. In these studies, silicon microdosimeters were used to measure lineal energy spectra in such radiation oncology modalities as boron-neutron capture therapy (BNCT) [3], [4] and Proton therapy [2]. Recently the technique has been applied to measurements in fast neutron therapy (FNT).…”