Kristoffer Petersson

Kristoffer Petersson
University of Oxford | OX · Department of Oncology

PhD

About

69
Publications
11,857
Reads
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1,961
Citations
Introduction
FLASH radiation is a novel radiotherapy technique that show great potential in improving cancer treatment. However, very little is known about the biological mechanisms behind the highly beneficial FLASH effect. Our research group aims to identify these mechanisms, explain the effect, and to find the optimal way of implementing the technique in clinical practice.
Additional affiliations
October 2019 - present
University of Oxford
Position
  • Group Leader
Description
  • Group Leader - Physics and Biology of FLASH Radiation
July 2017 - present
Skåne University Hospital and Lund University
Position
  • Medical Professional
June 2014 - June 2017
Lausanne University Hospital
Position
  • PostDoc Position
Education
February 2010 - February 2014
Lund University
Field of study
  • Medical Radiation Physics
August 2004 - June 2009
Lund University
Field of study
  • Medical radiation physics
January 2003 - April 2004
South Skåne Regiment (P7)
Field of study
  • Military service

Publications

Publications (69)
Article
Introduction To ensure a clinical translation of FLASH radiation therapy (FLASH-RT) for a specific tumor type, studies on tumor control and toxicity within the same biological system are needed. In this study, our objective was to evaluate tumor control and toxicity for hypofractionated FLASH-RT and conventional radiation therapy (CONV-RT) in an im...
Article
Full-text available
FLASH radiotherapy is a novel technique that has been shown in numerous preclinical in vivo studies to have the potential to be the next important improvement in cancer treatment. However, the biological mechanisms responsible for the selective FLASH sparing effect of normal tissues are not yet known. An optimal translation of FLASH radiotherapy in...
Article
Full-text available
Objective: FLASH irradiation reportedly produces less normal tissue toxicity, while maintaining tumour response. To investigate oxygen’s role in the ‘FLASH effect’, we assessed DNA damage levels following irradiation at different oxygen tensions, doses and dose rates. Methods: Samples of whole blood were irradiated (20 Gy) at various oxygen tensio...
Article
As radiotherapy using ultra-high dose rates has gained new interest, the dosimetric challenges arising at these conditions needs to be addressed. Ionization chambers suffer from a large decrease in ion collection efficiency due to ion recombination, making on-line dosimetry difficult. In this work we present experimental setups and dosimetric proce...
Article
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Purpose Hypoxia (low oxygen) is a common feature of solid tumors that has been intensely studied for more than six decades. Here we review the importance of hypoxia to radiotherapy with a particular focus on the contribution of hypoxia to immune responses, metastatic potential and FLASH radiotherapy, active areas of research by leading women in the...
Article
Purpose/Objective(s) Studies of electron FLASH radiotherapy (FLASH-RT) in companion animals are being conducted at several institutions. High energy electron beams are generally suitable for treatment of superficial cancers, but of limited use for deep-seated tumors. In this case report, the feasibility of intracavitary electron FLASH-RT is demonst...
Article
Full-text available
Introduction The aim of this study was to evaluate if surface guided radiotherapy (SGRT) can decrease patient positioning time for localized prostate cancer patients compared to the conventional 3-point localization setup method. The patient setup accuracy was also compared between the two setup methods. Materials and methods A total of 40 localiz...
Article
Purpose Preclinical studies using ultra-high dose rate (FLASH) irradiation have demonstrated reduced normal tissue toxicity compared to conventional dose rate (CONV) irradiation, although this finding is not universal. We investigated the effect of temporal pulse structure and average dose rate of FLASH compared to CONV irradiation, on acute intest...
Article
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Background Irradiation with ultra-high dose rate (FLASH) has been shown to spare normal tissue without hampering tumor control in several in vivo studies. Few cell lines have been investigated in vitro, and previous results are inconsistent. Assuming that oxygen depletion accounts for the FLASH sparing effect, no sparing should appear for cells irr...
Article
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Research efforts in FLASH radiotherapy have increased at an accelerated pace recently. FLASH radiotherapy involves ultra-high dose rates and has shown to reduce toxicity to normal tissue while maintaining tumor response in pre-clinical studies when compared to conventional dose rate radiotherapy. The goal of this review is to summarize the studies...
Article
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FLASH radiotherapy has emerged as a treatment technique with great potential to increase the differential effect between normal tissue toxicity and tumor response compared to conventional radiotherapy. To evaluate the feasibility of FLASH radiotherapy in a relevant clinical setting, we have commenced a feasibility and safety study of FLASH radiothe...
Article
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An electron beam of very high energy (50–250 MeV) can potentially produce a more favourable radiotherapy dose distribution compared to a state-of-the-art photon based radiotherapy technique. To produce an electron beam of sufficiently high energy to allow for a long penetration depth (several cm), very large accelerating structures are needed when...
Article
When relativistic electrons are used to irradiate tissues, such as during FLASH pre-clinical irradiations, the electron beam energy is one of the critical parameters that determine the dose distribution. Moreover, during such irradiations, linear accelerators (linacs) usually operate with significant beam loading, where a small change in the accele...
Article
Purpose: Recent data have shown that single-fraction irradiation delivered to the whole brain in less than tenths of a second using FLASH radiotherapy (FLASH-RT), does not elicit neurocognitive deficits in mice. This observation has important clinical implications for the management of invasive and treatment-resistant brain tumors that involves re...
Article
Full-text available
Purpose Ultra-high dose rate FLASH radiotherapy was shown to minimize side effects of irradiation in various organs while keeping anti-tumor efficacy. This property, called the FLASH effect, causes enthusiasm in radiation oncology community as it opens opportunities for safe dose escalation and improved radiotherapy outcome. Here, we investigated t...
Article
Full-text available
In the novel and promising radiotherapy technique known as FLASH, ultra-high dose-rate electron beams are used. As a step towards clinical trials, dosimetric advances will be required for accurate dose delivery of FLASH. The purpose of this study was to determine whether a built-in transmission chamber of a clinical linear accelerator can be used a...
Article
Overview The National Cancer Institute’s Radiation Research Program in collaboration with the Radiosurgery Society hosted a workshop on Understanding High-Dose, Ultra-High Dose rate and Spatially Fractionated Radiotherapy on August 20-21, 2018 to bring together experts in experimental and clinical experience in these and related fields. Critically,...
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Introduction Radiotherapy treatment planning is a multi-criteria problem. Any optimization of the process produces a set of mathematically optimal solutions. These optimal plans are considered mathematically equal, but they differ in terms of the trade-offs involved. Since the various objectives are conflicting, the choice of the best plan for trea...
Article
Background: Recent demonstrations of normal tissue sparing by high dose, high dose rate FLASH radiotherapy have driven considerable interest in its application to improve clinical outcomes. However, there remains significant uncertainty about the underlying mechanisms of FLASH sparing, and how deliveries can be optimised to maximize benefit from t...
Article
Full-text available
Radiotherapy is a cornerstone of both curative and palliative cancer care. However, radiotherapy is severely limited by radiation-induced toxicities. If these toxicities could be reduced, a greater dose of radiation could be given therefore facilitating a better tumor response. Initial pre-clinical studies have shown that irradiation at dose rates...
Article
Objectives: Recent in vivo results have shown prominent tissue sparing effect of radiotherapy with ultra-high dose rates (FLASH) compared to conventional dose rates (CONV). Oxygen depletion has been proposed as the underlying mechanism, but in vitro data to support this has been lacking. The aim of the current study was to compare FLASH to CONV ir...
Article
Background Patients with esophageal cancer commonly suffer from dysphagia, leading to nutritional problems and impaired quality of life. Self-expanding metallic stents (SEMS) is frequently used in the palliative setting providing a rapid but short-term relief. In this phase II study we assessed a novel first-line treatment schedule with short-cours...
Article
Full-text available
Background: The majority of patients with incurable esophageal adenocarcinoma suffer from dysphagia. We assessed a novel treatment strategy with initial short-course radiotherapy followed by chemotherapy with the primary aim to achieve long-term relief of dysphagia. Methods: This phase II trial included treatment-naîve patients with dysphagia due t...
Article
Purpose: Preclinical studies using a new treatment modality called FLASH Radiotherapy (FLASH-RT) need a two-phase procedure to ensure minimal uncertainties in the delivered dose. The first phase requires a new investigation of the reference dosimetry lying outside the conventional metrology framework from national metrology institutes but necessar...
Article
Full-text available
Here, we highlight the potential translational benefits of delivering FLASH radiotherapy using ultra-high dose rates (>100 Gy⋅s ⁻¹ ). Compared with conventional dose-rate (CONV; 0.07–0.1 Gy⋅s ⁻¹ ) modalities, we showed that FLASH did not cause radiation-induced deficits in learning and memory in mice. Moreover, 6 months after exposure, CONV caused...
Article
Objectives: The purpose of this study was to modify a clinical linear accelerator, making it capable of electron beam ultra-high dose rate (FLASH) irradiation. Modifications had to be quick, reversible, and without interfering with clinical treatments. Methods: Performed modifications: (1) reduced distance with three setup positions, (2) adjuste...
Data
https://prezi.com/69rn4_1gg03x/optimising-the-clinical-use-of-tomotherapy/
Article
Full-text available
Background and purpose: Adjuvant radiation therapy (RT) of the whole breast (WB) is still the standard treatment for early breast cancer. A variety of radiation techniques is currently available according to different delivery strategies. This study aims to provide a comparison of six treatment planning strategies commonly adopted for breast-conse...
Article
This study is the first proof of concept that the FLASH effect can be triggered by X-rays. Our results show that a 10 Gy whole-brain irradiation delivered at ultra-high dose-rate with synchrotron generated X-rays does not induce memory deficit; it reduces hippocampal cell-division impairment and induces less reactive astrogliosis.
Article
Background: Previous studies using FLASH radiotherapy (RT) in mice showed a marked increase of the differential effect between normal tissue and tumors. To stimulate clinical transfer, we evaluated whether this effect could also occur in higher mammals. Methods: Pig skin was used to investigate a potential difference in toxicity between irradiat...
Article
Purpose: The Oriatron eRT6 is an experimental high dose-per-pulse linear accelerator (linac) which was designed to deliver an electron beam with variable dose-rates, ranging from a few Gy/min up to hundreds of Gy/s. It was built to study the radiobiological effects of high dose-per-pulse/dose-rate electron beam irradiation, in the context of precl...
Article
Background and purpose: Treatment plan evaluation is a clinical decision-making problem that involves visual search and analysis in a contextually rich environment, including delineated structures and isodose lines superposed on CT data. It is a two-step process that includes visual analysis and clinical reasoning. In this work, we used eye tracki...
Article
Full-text available
We present a clinical distance measure for Pareto front evaluation studies in radiotherapy, which we show strongly correlates (r = 0.74 and 0.90) with clinical plan quality evaluation. For five prostate cases, sub-optimal treatment plans located at a clinical distance value of >0.32 (0.28–0.35) from fronts of Pareto optimal plans, were assessed to...
Article
This study shows for the first time that normal brain tissue toxicities after WBI can be reduced with increased dose rate. Spatial memory is preserved after WBI with mean dose rates above 100 Gy/s, whereas 10 Gy WBI at a conventional radiotherapy dose rate (0.1 Gy/s) totally impairs spatial memory.
Article
Purpose: The purpose of this work was to establish an empirical model of the ion recombination in the Advanced Markus ionization chamber for measurements in high dose rate/dose-per-pulse electron beams. In addition, we compared the observed ion recombination to calculations using the standard Boag two-voltage-analysis method, the more general theo...
Article
Purpose: The aim of this study was to assess the suitability of Gafchromic EBT3 films for reference dose measurements in the beam of a prototype high dose-per-pulse linear accelerator (linac), capable of delivering electron beams with a mean dose-rate (Ḋm ) ranging from 0.07 to 3000 Gy/s and a dose-rate in pulse (Ḋp ) of up to 8·10(6) Gy/s. To do...
Article
Multi-criteria optimization provides decision makers with a range of clinical choices through Pareto plans that can be explored during real time navigation and then converted into deliverable plans. Our study shows that dosimetric differences can arise between the two steps, which could compromise the clinical choices made during navigation.
Article
Background and purpose The purpose of this study was to investigate the correlation between the haematological toxicity observed in patients treated with craniospinal irradiation, and the dose distribution in normal tissue, specifically the occurrence of large volumes exposed to low dose. Materials and methods Twenty adult male patients were inclu...
Thesis
Full-text available
Radiotherapy is one of the major tools for treating cancer. Through research and technical development radiotherapy is becoming more advanced with new treatment techniques emerging. In the work presented in this thesis, well-known methods have been used, or modified for use, and new methods have been introduced in order to optimise the clinical use...
Article
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Purpose: In this work we explore a method named clinical grading analysis (CGA) which is based on clinical assessments performed by radiation oncologists (ROs). The purpose is to investigate how useful the method is for treatment plan comparisons, and how the CGA results correlate with dosimetric evaluation parameters, traditionally used for treat...
Article
Full-text available
Purpose/Objective: In this study we have looked at acute haematological effects of the dose bath on adult patients treated with cranio-spinal irradiation (CSI). CSI treatments were decided to be delivered with helical tomotherapy when it became available at our clinic. However, it was soon discovered that these patients exhibited acute haematologic...
Article
The resulting plans from a new type of treatment planning system called SharePlan have been studied. This software allows for the conversion of treatment plans generated in a TomoTherapy system for helical delivery, into plans deliverable on C-arm linear accelerators (linacs), which is of particular interest for clinics with a single TomoTherapy un...
Article
Full-text available
Purpose: Treatment with helical tomotherapy is beneficial for many patients compared to treatment with a conventional C-arm linac. To be able to treat more patients with tomotherapy the total treatment time per fraction for every patient has to be shortened. One way of doing this is to replace the time consuming use of MVCT imaging for positioning...
Article
Purpose: It is common for radiation oncologists (ROs) today to have a mixed arsenal of radiotherapy treatment modalities at their disposal. To optimize a clinic’s use of its different treatment modalities, while at the same time giving every patient an optimal treatment, is not a trivial task. The purpose of this study was to give ROs a tool to cho...
Article
A new type of treatment planning system called SHAREPLAN has been studied, which enables the transfer of treatment plans generated for helical tomotherapy delivery to plans that can be delivered on C-arm linacs. The purpose is to ensure continuous patient treatment during periods of unscheduled downtime for the TomoTherapy unit, particularly in cli...
Thesis
Full-text available
Introduction: SharePlanTM is a new type of treatment planning system produced by RaySearch Laboratories AB for TomoTherapy Inc. SharePlan enables transfer of treatment plans generated with the TomoTherapy Hi∙Art® system to plans deliverable at conventional linacs. The main reason for this is to ensure continuous patient treatment if the TomoTherap...

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