# Field Shaping Scintillator-coupled High-gain Avalanche Rushing Photoconductor (SHARP) for Active Matrix Flat Panel Imager (AMFPI): Towards Large-Area, High-Efficiency, and Low-Dose X-ray Imaging

> **NIH NIH R21** · STATE UNIVERSITY NEW YORK STONY BROOK · 2020 · $236,758

## Abstract

Abstract
 The field of medical x-ray imaging experienced a "digital revolution" in the early 2000s, with the
spreading of digital radiography (DR) systems which are based on active matrix flat panel imagers
(AMFPI). Since then we have seen rapid development and clinical translation of large-area AMFPI
based on amorphous silicon (a-Si) active matrix technology. Because of their compact size, rapid
image readout and excellent image quality, AMFPI is being used not only for traditional x-ray
imaging modalities such as general radiography and fluoroscopy, but also in tomographic imaging
applications including cone beam computed tomography (CBCT) and digital tomosynthesis. It is
believed that AMFPI will become the dominant detector technology for x-ray imaging. However
before AMFPI can equal the performance of the x-ray image intensifier (XRII) in fluoroscopy, they
have one major difficulty to overcome: producing x-ray quantum noise limited images at very low
dose, such as in the dark part of a fluoroscopy image (0.1 R per frame). Our hypothesis is that
an indirect-conversion x-ray flat-panel imager with avalanche gain and cadmium selenide (CdSe)
photoelectric conversion layer will provide an enormous dynamic range and efficiency that permits
x-ray quantum noise limited performance from a single x-ray photon level in low-dose fluoroscopy
all the way to high dose radiography. The objective of this proposal is therefore to fabricate and
test a prototype high-efficiency flat-panel x-ray imaging detector with avalanche gain. Conceptually the proposed detector employs four major components: (1) a structured cesium iodide (CsI)
scintillator to convert x-rays to optical photons; (2) an ultra-high efficiency CdSe photoelectric
conversion layer to convert the optical image to charge; (3) field shaping avalanche amorphous selenium (a-Se) photoconductor, called field shaping HARP (High-gain Avalanche Rushing amorphous
Photoconductor), to amplify charge via avalanche multiplication gain; and (4) a large area active
matrix (AM) thin film transistor (TFT) array to read out the image electronically in real-time. The
proposed detector is known as "field shaping SHARP-AMFPI (Scintillator-HARP Active
Matrix Flat-Panel Imager)". Successful development of field-shaping SHARP-AMFPI will lead
to the clinical-translation ready, practical low-dose x-ray imaging technology, which will be the first
ever large area solid-state detector with stable avalanche gain.

## Key facts

- **NIH application ID:** 9841399
- **Project number:** 5R21EB025300-03
- **Recipient organization:** STATE UNIVERSITY NEW YORK STONY BROOK
- **Principal Investigator:** Amirhossein Goldan
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $236,758
- **Award type:** 5
- **Project period:** 2018-01-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9841399

## Citation

> US National Institutes of Health, RePORTER application 9841399, Field Shaping Scintillator-coupled High-gain Avalanche Rushing Photoconductor (SHARP) for Active Matrix Flat Panel Imager (AMFPI): Towards Large-Area, High-Efficiency, and Low-Dose X-ray Imaging (5R21EB025300-03). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9841399. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*