Johns Hopkins University
Radiation Oncology and Molecular Radiation Sciences
I am a senior medical physicist and an assistant professor in the Department of Radiation Oncology and Molecular Radiation Sciences in Johns Hopkins School of Medicine, and physics advisor of advanced preclinical radiation research at the Sidney Kimmel Comprehensive Cancer Center. My research interest is radiation physics, biophysics, and their exploitation to improve the efficacy of radiotherapy using different methods including FLASH radiotherapy, high-LET radiotherapy, radiosensitizers, and Auger-electron emitting radionuclides. One of my major focuses is to develop FLASH radiotherapy for preclinical studies, elucidation of its biophysical/biological mechanisms, and its translation into clinical practices. I have invented an orthovoltage x-ray FLASH irradiator for preclinical laboratory research on small animals and cell cultures.

Presenter of 1 Presentation

A NOVEL SELF-SHIELDED X-RAY IRRADIATION SYSTEM FOR LABORATORY FLASH RADIATION RESEARCH

Session Name
Session Type
FLASH Modalities Track (Oral Presentations)
Date
Wed, 01.12.2021
Session Time
18:00 - 19:00
Room
Room 2.31
Lecture Time
18:10 - 18:20

Abstract

Background and Aims

Pre-clinical laboratory research to elucidate biological effects of FLASH irradiation is imperative to support its clinical translation. At present, FLASH research employs complex accelerator technologies of limited accessibilities. Here, we introduce a novel self-shielded FLASH x-ray cabinet system to support preclinical research.

Methods

The proposed system employs two commercially available high-capacity 150 kVp x-ray sources with rotating anode technology in a parallel-opposed arrangement. X-ray sources are supported by independent bidirectional computer-controlled vertical and rotational motions for conformal and angled irradiation (Figure 1). A radiochromic film validated Monte-Carlo simulation platform (Geant4) was used to characterize the dosimetry of the system.

picture1.jpg

Results

This system delivers doses up to 67 Gy to a 20-mm thick water equivalent medium at both FLASH and conventional dose-rates of 40-240 Gy/s and <0.1 Gy/s, respectively. Depth dose-rate uniformity (±5%) is achieved over 8-12 mm in the central region of the medium. The mirrored beams minimize heel effect of the source and achieve cross-beam uniformity within ±3%. Field dimension is adjustable, ranging from 0.1–5.5 cm and 0.1–20 cm for FLASH and conventional irradiation, respectively, suitable for small animal and cell culture irradiations. Angling the two beams minimizes entrance and exit beams overlap, and reduces surface doses up to 39%.

Conclusions

This system greatly enhances FLASH radiation research in regular laboratory setting. In-vivo studies are being conducted to demonstrate kVp x-rays induced FLASH effects on superficial murine models. Results will be presented.

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Author Of 1 Presentation

A NOVEL SELF-SHIELDED X-RAY IRRADIATION SYSTEM FOR LABORATORY FLASH RADIATION RESEARCH

Session Name
Session Type
FLASH Modalities Track (Oral Presentations)
Date
Wed, 01.12.2021
Session Time
18:00 - 19:00
Room
Room 2.31
Lecture Time
18:10 - 18:20

Abstract

Background and Aims

Pre-clinical laboratory research to elucidate biological effects of FLASH irradiation is imperative to support its clinical translation. At present, FLASH research employs complex accelerator technologies of limited accessibilities. Here, we introduce a novel self-shielded FLASH x-ray cabinet system to support preclinical research.

Methods

The proposed system employs two commercially available high-capacity 150 kVp x-ray sources with rotating anode technology in a parallel-opposed arrangement. X-ray sources are supported by independent bidirectional computer-controlled vertical and rotational motions for conformal and angled irradiation (Figure 1). A radiochromic film validated Monte-Carlo simulation platform (Geant4) was used to characterize the dosimetry of the system.

picture1.jpg

Results

This system delivers doses up to 67 Gy to a 20-mm thick water equivalent medium at both FLASH and conventional dose-rates of 40-240 Gy/s and <0.1 Gy/s, respectively. Depth dose-rate uniformity (±5%) is achieved over 8-12 mm in the central region of the medium. The mirrored beams minimize heel effect of the source and achieve cross-beam uniformity within ±3%. Field dimension is adjustable, ranging from 0.1–5.5 cm and 0.1–20 cm for FLASH and conventional irradiation, respectively, suitable for small animal and cell culture irradiations. Angling the two beams minimizes entrance and exit beams overlap, and reduces surface doses up to 39%.

Conclusions

This system greatly enhances FLASH radiation research in regular laboratory setting. In-vivo studies are being conducted to demonstrate kVp x-rays induced FLASH effects on superficial murine models. Results will be presented.

Hide