Small-scale (sub-organ and cellular level) alpha-particle dosimetry methods using an iQID digital autoradiography imaging system

Abstract

Targeted radiopharmaceutical therapy with alpha-particle emitters (αRPT) is advantageous in cancer treatment because the short range and high local energy deposition of alpha particles enable precise radiation delivery and efficient tumor cell killing. However, these properties create sub-organ dose deposition effects that are not easily characterized by direct gamma-ray imaging (PET or SPECT). We present a computational procedure to determine the spatial distribution of absorbed dose from alpha-emitting radionuclides in tissues using digital autoradiography activity images from an ionizing-radiation quantum imaging detector (iQID). Data from 211At-radioimmunotherapy studies for allogeneic hematopoietic cell transplantation in a canine model were used to develop these methods. Nine healthy canines were treated with 16.9–30.9 MBq 211At/mg monoclonal antibodies (mAb). Lymph node biopsies from early (2–5 h) and late (19–20 h) time points (16 total) were obtained, with 10–20 consecutive 12-µm cryosections extracted from each and imaged with an iQID device. iQID spatial activity images were registered within a 3D volume for dose-point-kernel convolution, producing dose-rate maps. The accumulated absorbed doses for high- and low-rate regions were 9 ± 4 Gy and 1.2 ± 0.8 Gy from separate dose-rate curves, respectively. We further assess uptake uniformity, co-registration with histological pathology, and requisite slice numbers to improve microscale characterization of absorbed dose inhomogeneities in αRPT.

Development of an ultrahigh resolution real time alpha particle imaging system for observing the trajectories of alpha particles in a scintillator

“…High-resolution alpha-particle imaging is required for the distribution measurements in cells or dissected animals for the development of new radio-compounds and dosimetry for targeted alpha-particle therapy 1 – 3 . High-resolution alpha-particle imaging is also required for distribution measurements in mineralogical studies 4 .…”

Sub-micrometer real-time imaging of trajectory of alpha particles using GAGG plate and CMOS camera

“…The major properties of the GAGG used in our alpha-particle imaging experiments are density of 6.63 g/cm 3 , maximum emission light wavelength of 520 nm, and the light emission of 45,000-50,000 photons/MeV [18].…”

“…High-resolution and real-time imaging of the trajectories of alpha particles is desired in nuclear medicine and nuclear engineering fields. For example, alpha-particle imaging is required for the distribution measurements in cells or dissected animals in research on the development of radiocompounds in targeted alpha-particle therapy [1][2][3]. High-resolution alpha-particle imaging is also required for mineralogical studies [4] and at nuclear fuel facilities where plutonium (Pu) is used [5,6].…”

Development of an ultrahigh-resolution, real-time alpha-particle imaging system for observing the trajectories of alpha particles in a scintillator

“…High-resolution alpha-particle imaging is required for the distribution measurements in cells or dissected animals for the development of new radio-compounds and dosimetry for targeted alpha-particle therapy [1][2][3]. High-resolution alpha-particle imaging is also required for distribution measurements in mineralogical studies [4] as well as plutonium (Pu) particle detection at nuclear facilities [5][6].…”