3D Printing of Composite Radiation Shielding for Broad Spectrum Protection of Electronic Systems.

The miniaturization of satellite systems has compounded the need to protect microelectronic components from damaging radiation. Current approaches to mitigate this damage, such as indiscriminate mass shielding, built-in redundancies, and radiation-hardened electronics, introduce high size, weight, power, and cost penalties that impact the overall performance of the satellite or launch opportunities. Additive manufacturing provides an appealing strategy to deposit radiation shielding only on susceptible components within an electronic assembly.

Voxel-wise dose rate calculation in clinical pencil beam scanning proton therapy.

. Clinical outcomes after proton therapy have shown some variability that is not fully understood. Different approaches have been suggested to explain the biological outcome, but none has yet provided a comprehensive and satisfactory rationale for observed toxicities.

Absence of Tissue-Sparing Effects in Partial Proton FLASH Irradiation in Murine Intestine.

Ultra-high dose rate irradiation has been reported to protect normal tissues more than conventional dose rate irradiation. This tissue sparing has been termed the FLASH effect. We investigated the FLASH effect of proton irradiation on the intestine as well as the hypothesis that lymphocyte depletion is a cause of the FLASH effect.

Proton FLASH effects on mouse skin at different oxygen tensions.

. Irradiation at FLASH dose rates (>40 Gy s) has received great attention due to its reported normal tissue sparing effect. The FLASH effect was originally observed in electron irradiations but has since been shown to also occur with both photon and proton beams.

FLASH Investigations Using Protons: Design of Delivery System, Preclinical Setup and Confirmation of FLASH Effect with Protons in Animal Systems.

Extremely high-dose-rate irradiation, referred to as FLASH, has been shown to be less damaging to normal tissues than the same dose administrated at conventional dose rates. These results, typically seen at dose rates exceeding 40 Gy/s (or 2,400 Gy/min), have been widely reported in studies utilizing photon or electron radiation as well as in some proton radiation studies. Here, we report the development of a proton irradiation platform in a clinical proton facility and the dosimetry methods developed.

Iterative optimization of relative stopping power by single detector based multi-projection proton radiography.

In proton therapy, range uncertainties induced by the conversion from x-ray CT (xCT) Hounsfield units (HU) to relative stopping power (RSP) compromise the precision of dose delivery. To reduce range uncertainties induced by HU-converted RSPs, this study investigates optimizing the RSP of individual voxels in xCT iteratively based on multi-projection proton radiography (pRG) acquired using a single amorphous silicon flat panel imager. Time-resolved dose rate functions (DRF) were measured by the imager placed downstream of a test phantom consisting of tissue substitute materials.

Improvement of single detector proton radiography by incorporating intensity of time-resolved dose rate functions.

Proton radiography, which images patients with the same type of particles as those with which they are to be treated, is a promising approach to image guidance and water equivalent path length (WEPL) verification in proton radiation therapy. We have shown recently that proton radiographs could be obtained by measuring time-resolved dose rate functions (DRFs) using an x-ray amorphous silicon flat panel. The WEPL values were derived solely from the root-mean-square (RMS) of DRFs, while the intensity information in the DRFs was filtered out.

On the nuclear halo of a proton pencil beam stopping in water.

The dose distribution of a proton beam stopping in water has components due to basic physics and may have others from beam contamination. We propose the concise terms core for the primary beam, halo (see Pedroni et al 2005 Phys. Med.

Validation of an in-vivo proton beam range check method in an anthropomorphic pelvic phantom using dose measurements.

Purpose: In-vivo dosimetry and beam range verification in proton therapy could play significant role in proton treatment validation and improvements. In-vivo beam range verification, in particular, could enable new treatment techniques one of which could be the use of anterior fields for prostate treatment instead of opposed lateral fields as in current practice. This paper reports validation study of an in-vivo range verification method which can reduce the range uncertainty to submillimeter levels and potentially allow for in-vivo dosimetry.

Radiation resistance of biological reagents for in situ life detection.

Life on Mars, if it exists, may share a common ancestry with life on Earth derived from meteoritic transfer of microbes between the planets. One means to test this hypothesis is to isolate, detect, and sequence nucleic acids in situ on Mars, then search for similarities to known common features of life on Earth. Such an instrument would require biological and chemical components, such as polymerase and fluorescent dye molecules.

Investigation of an implantable dosimeter for single-point water equivalent path length verification in proton therapy.

Purpose: In vivo range verification in proton therapy is highly desirable. A recent study suggested that it was feasible to use point dose measurement for in vivo beam range verification in proton therapy, provided that the spread-out Bragg peak dose distribution is delivered in a different and rather unconventional manner. In this work, the authors investigate the possibility of using a commercial implantable dosimeter with wireless reading for this particular application.

PET/CT imaging for treatment verification after proton therapy: a study with plastic phantoms and metallic implants.

The feasibility of off-line positron emission tomography/computed tomography (PET/CT) for routine three dimensional in-vivo treatment verification of proton radiation therapy is currently under investigation at Massachusetts General Hospital in Boston. In preparation for clinical trials, phantom experiments were carried out to investigate the sensitivity and accuracy of the method depending on irradiation and imaging parameters. Furthermore, they addressed the feasibility of PET/CT as a robust verification tool in the presence of metallic implants.

Dose-volume prediction of radiation-related complications after proton beam radiosurgery for cerebral arteriovenous malformations.

Object: The use of radiosurgery for the treatment of cerebral arteriovenous malformations (AVMs) and other lesions demands an accurate understanding of the risk of radiation-related complications. Some commonly used formulas for predicting risk are based on extrapolation from small numbers of animal experiments, pilot human treatment series, and theoretical radiobiological considerations. The authors studied the incidence of complications after AVM radiosurgery in relation to dose, volume, and other factors in a large patient series.