scholarly journals Cancer radiotherapy based on femtosecond IR laser-beam filamentation yielding ultra-high dose rates and zero entrance dose

2012 ◽  
Vol 109 (38) ◽  
pp. E2508-E2513 ◽  
Author(s):  
Ridthee Meesat ◽  
Hakim Belmouaddine ◽  
Jean-François Allard ◽  
Catherine Tanguay-Renaud ◽  
Rosalie Lemay ◽  
...  
Keyword(s):  
Tumor Volume ◽  
Aqueous Media ◽  
Laser Pulses ◽  
Infrared Laser ◽  
High Dose ◽  
X Rays ◽  
Cancer Radiotherapy ◽  
Dose Rates ◽  
Therapeutic Benefits ◽  
Entrance Dose

Since the invention of cancer radiotherapy, its primary goal has been to maximize lethal radiation doses to the tumor volume while keeping the dose to surrounding healthy tissues at zero. Sadly, conventional radiation sources (γ or X rays, electrons) used for decades, including multiple or modulated beams, inevitably deposit the majority of their dose in front or behind the tumor, thus damaging healthy tissue and causing secondary cancers years after treatment. Even the most recent pioneering advances in costly proton or carbon ion therapies can not completely avoid dose buildup in front of the tumor volume. Here we show that this ultimate goal of radiotherapy is yet within our reach: Using intense ultra-short infrared laser pulses we can now deposit a very large energy dose at unprecedented microscopic dose rates (up to 1011 Gy/s) deep inside an adjustable, well-controlled macroscopic volume, without any dose deposit in front or behind the target volume. Our infrared laser pulses produce high density avalanches of low energy electrons via laser filamentation, a phenomenon that results in a spatial energy density and temporal dose rate that both exceed by orders of magnitude any values previously reported even for the most intense clinical radiotherapy systems. Moreover, we show that (i) the type of final damage and its mechanisms in aqueous media, at the molecular and biomolecular level, is comparable to that of conventional ionizing radiation, and (ii) at the tumor tissue level in an animal cancer model, the laser irradiation method shows clear therapeutic benefits.

Survival of mammalian cells exposed to X rays at ultra-high dose-rates

1969 ◽  
Vol 42 (494) ◽  
pp. 102-107 ◽  
Author(s):  
Roger J. Berry ◽  
Eric J. Hall ◽  
David W. Forster ◽  
Thomas H. Storr ◽  
Michael J. Goodman
Keyword(s):  
Mammalian Cells ◽  
High Dose ◽  
X Rays ◽  
Dose Rates

Absorbed dose-to-water protocol applied to synchrotron-generated x-rays at very high dose rates

2016 ◽  
Vol 61 (14) ◽  
pp. N349-N361 ◽  
Author(s):  
P Fournier ◽  
J C Crosbie ◽  
I Cornelius ◽  
P Berkvens ◽  
M Donzelli ◽  
...  
Keyword(s):  
Absorbed Dose ◽  
High Dose ◽  
X Rays ◽  
Dose Rates ◽  
Absorbed Dose To Water ◽  
Very High

THE PRODUCTION OF MUTATIONS BY THE IRRADIATION OF MONTCALM BARLEY

1955 ◽  
Vol 33 (6) ◽  
pp. 515-530 ◽  
Author(s):  
Thomas Lawrence
Keyword(s):  
High Dose Rate ◽  
Mutation Induction ◽  
High Dose ◽  
X Rays ◽  
New Approach ◽  
X Ray ◽  
Dose Rates ◽  
Radiation Sources ◽  
Early Maturing ◽  
New Varieties

Five radiation sources were used to induce mutations in barley. All treatments were given at a dosage of 10,000 r. equivalent. The radiation sources with their respective dose-rates in the region of the irradiated seeds were: a betatron (181.8 r./min.), an X-ray machine (201 r./min.), radium-beryllium (5.3 r./min.), and two Co60 sources (4.5 r./min. and 75.75 r./min.). None of the radiation sources used was more effective than the X-ray treatment in producing mutations. The betatron and the high dose-rate treatments from Co60 appear to be somewhat less effective than X-rays. Over 30 different mutant types were produced, including a number of vital mutants, such as stiff-strawed and early-maturing types. These appear promising as new varieties, but require further agronomic evaluation. It is concluded that mutation induction will become a useful new approach for plant breeders.

scholarly journals X-ray Emission Hazards from Ultrashort Pulsed Laser Material Processing in an Industrial Setting

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7163
Author(s):  
Ulf Stolzenberg ◽  
Mayka Schmitt Rahner ◽  
Björn Pullner ◽  
Herbert Legall ◽  
Jörn Bonse ◽  
...  
Keyword(s):  
Material Processing ◽  
High Dose ◽  
Reference Scenario ◽  
X Rays ◽  
Laser Material Processing ◽  
Laser Material ◽  
X Ray ◽  
Dose Rates ◽  
Industrial Setting ◽  
Ambient Dose

Interactions between ultrashort laser pulses with intensities larger than 1013 W/cm2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 1015 W/cm2 at pulse durations of ~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified.

Radiation therapy in the management of gynaecological cancer

2020 ◽  
pp. 832-843
Author(s):  
Anthony Fyles ◽  
Anuja Jhingran ◽  
David Gaffney ◽  
Dustin Boothe ◽  
Marco Carlone ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
World War Ii ◽  
Radiation Treatment ◽  
Uterine Cancer ◽  
High Dose Rate ◽  
Gynaecological Cancer ◽  
High Dose ◽  
External Beam ◽  
X Rays ◽  
Dose Rates

Therapeutic applications for radiation therapy followed quickly from the discovery of X-rays by Roentgen in 1895. The first radiation treatment is credited to Grubbe, who reported the external beam treatment of breast cancer in 1896. Application to gynaecological cancers was almost immediate. However, the limited penetrating ability of the low-energy radiation of early X-ray tubes and isotopes was a major limitation. Consequently, brachytherapy and near-contact external beam therapy were preferred for gynaecological cancer until the advent of cobalt-60—the first source of a penetrating beam of megavoltage photons with a high dose rate, long half-life, and reasonable cost. This led to cobalt-60 machines becoming the most widely utilized treatment machine from the 1950s to 1970s. Radar research during World War II dramatically improved microwave technology. Linear accelerator-based machines (linacs) applied these advances to use microwaves to accelerate electrons onto a tungsten target and emit a fraction of their kinetic energy as mega-electron volt energy X-rays. The emitted X-rays are collimated into a beam and directed towards the patient. Advantages of linacs over cobalt-60 include higher dose rates, sharper beam edges, higher energies, and simplified radiation protection. This chapter describes the basic principles of radiotherapy and the role of radiotherapy in the management of gynaecological cancers, including cervix cancer, uterine cancer, and rarer tumours such as those arising from vaginal, vulvar, and ovarian cancers.

scholarly journals Can high dose rates used in cancer radiotherapy change therapeutic effectiveness?

2016 ◽  
Vol 6 ◽  
pp. 449-452 ◽  
Author(s):  
Maria Konopacka ◽  
Jacek Rogoliński ◽  
Aleksander Sochanik ◽  
Krzysztof Ślosarek
Keyword(s):  
Therapeutic Effectiveness ◽  
High Dose ◽  
Cancer Radiotherapy ◽  
Dose Rates

scholarly journals Development of a Portable Hypoxia Chamber for Ultra-high Dose Rate Laser-Driven Proton Radiobiology Applications

2021 ◽  
Author(s):  
Pankaj Chaudhary ◽  
Deborah Caroline Gwynne ◽  
Boris Odlozilik ◽  
Aaron McMurray ◽  
Giuliana Milluzzo ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dose Rate ◽  
Oxygen Concentration ◽  
High Dose Rate ◽  
High Dose ◽  
X Rays ◽  
Enhancement Ratio ◽  
Dose Rates ◽  
Oxygen Enhancement Ratio ◽  
Oxygen Enhancement

Abstract BackgroundThere is currently significant interest in assessing the role of oxygen in the radiobiological effects at ultra-high dose rates. Oxygen modulation is postulated to play a role in the enhanced sparing effect observed in FLASH radiotherapy, where particles are delivered at 40-1000 Gy/s. Furthermore, the development of laser-driven accelerators now enables radiobiology experiments in extreme regimes where dose rates can exceed 10^9 Gy/s, and predicted oxygen depletion effects on cellular response can be tested. Access to appropriate experimental enviroments, allowing measurements under controlled oxygenation conditions, is a key requirement for these studies. We report on the development and application of a bespoke portable hypoxia chamber specifically designed for experiments employing laser-driven sources, but also suitable for comparator studies under FLASH and conventional irradiation conditions.Materials and MethodsWe used oxygen concentration measurements to test the induction of hypoxia and the maintenance capacity of the chambers. Cellular hypoxia induction was verified using hypoxia inducible factor-1α immunostaining. Calibrated radiochromic films and GEANT-4 simulations verified the dosimetry variations inside and outside the chambers. We irradiated hypoxic human skin fibroblasts (AG01522B) and patient-derived glioblastoma (E2) cancer stem cells with laser-driven protons, conventional protons and reference 225 kVp X-rays to quantify DNA DSB damage and repair under hypoxia. We further measured the oxygen enhancement ratio for cell survival exposed to cyclotron-accelerated protons and X-rays in the normal fibroblast and radioresistant GBM stem cells. ResultsOxygen measurements showed that our chambers maintained a radiobiological hypoxic environment for at least 45 minutes and pathological hypoxia for up to 24 hrs after disconnecting the chambers from the gas supply. We observed a significant reduction in the 53BP1 foci induced by laser-driven protons, conventional protons and X-rays in the hypoxic cells compared to normoxic cells at 30 minutes post-irradiation. Under hypoxic irradiations, the Laser-driven protons induced significant residual DNA DSB damage in hypoxic AG01522 cells compared to the conventional dose rate protons suggesting an important impact of these extreme high dose-rate exposures. We obtained an oxygen enhancement ratio (OER) of 2.1 ± 0.108 and 2.501 ±0.125 respectively for the AG01522 and patient derived GBM stem cells for the X-rays using our hypoxia chambers for irradiation. ConclusionWe demonstrated the design and application of portable hypoxia chambers for studying cellular radiobiological endpoints after laser-driven protons at ultra-high dose, conventional protons and X-ray exposures. Good levels of reduced oxygen concentration could be maintained in the absence of external gassing to quantify hypoxic effects and the data obtained provided an indication of an enhanced residual DNA DSB damage under hypoxic conditions at ultra-high dose rate compared to the conventional protons or X-rays.

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