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Medical and Biological Applications of Low Energy Accelerators
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
Proton therapy is an advanced form of radiation therapy that uses a high-energy proton beam for cancer treatment. In contrast to conventional photon-based radiation therapy, proton beam delivers the majority of their destructive energy within a small range inside the tumor, known as the Bragg peak, thereby reducing adverse effects to adjacent healthy tissues. In IBA-equipped proton therapy centers, cyclotrons accelerate protons to an extremely high speed, generating a controlled beam, which is delivered very precisely in the treatment rooms, through a nozzle, to the targeted tumor. With proton therapy, there is significant potential to reduce side effects, improve overall outcomes in cancer treatment and offer a better quality of life to patients.
Radiation Protection of the Patient
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
W. P. M. Mayles, Uwe Schneider
The situation is different in proton therapy. Protons produce neutrons by inelastic nuclear interactions with material in the beam line as well as within the patient (see Section 25.2). However, neutron dose for scanned proton therapy comes more or less only from neutrons produced in the patient, whereas in passively scattered proton therapy, most energy is deposited by neutrons produced upstream in the beam line. These differences are illustrated in Figure 61.3, which shows that the neutron dose equivalent can be an order of magnitude larger for passive proton therapy. Figure 61.3 also shows peripheral photon doses from low-energy 3D CRT and IMRT treatments, respectively. Clearly, the neutron dose from proton therapy is lower than the combination of scatter and leakage in photon therapy. However, it should be noted that Figure 61.3 does not include the dose from prompt gamma radiation as a result of proton irradiation. In summary, neutron dose resulting from proton therapy is well balanced by the integral dose advantage of the protons when compared with photon therapy (Section 39.1). As such, it is expected that second cancer induction will not be higher after proton therapy and might even be lower (~50%) when pencil-beam scanning is used. This is in general agreement with epidemiological results published by Chung et al. (2013).
Radiotherapy Physics
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Andrea Wynn-Jones, Caroline Reddy, John Gittins, Philip Baker, Anna Mason, Greg Jolliffe
The use of high linear energy transfer (LET) radiation, such as proton therapy, is also possible. Proton therapy potentially offers some advantages to using high-energy X-rays, relating to the physics of how the radiation dose is distributed in the target, but is not suitable for all patients. NHS proton therapy facilities in the UK are currently limited to a small number of specialist centres.
“I don’t want to hear statistics, I want real life stories”: Systematic review and thematic synthesis of patient and caregiver experiences of Proton Beam Therapy
Published in Journal of Psychosocial Oncology, 2023
Emma Fiddimore, Emily Harrop, Annmarie Nelson, Stephanie Sivell
The theme of living in a “bubble” during PBT treatment was inextricably linked to instances where participants had traveled abroad or across the country to receive treatment. As of 2021, there were around 100 proton therapy centers worldwide, which are widely spread, and some patients travel long distances to reach their center.17 This raises the issue of equity of access for treatment; in this review, many of those considering PBT stated there are financial or social barriers to receiving treatment far from home, such as loss of income and lack of childcare.31,35,36 This inequity is not unique to PBT—similar findings are observed for other advanced cancer therapies, such as cell immunotherapy, which is not widely available but is subject to media sensationalism surrounding its novelty, making it desirable to patients despite low accessibility.54,55 Addressing these inequities should be a priority of health providers for the future of these treatments.
Transitioning from conventional photon therapy to proton therapy for primary brain tumors
Published in Acta Oncologica, 2023
Hanna Ek, Ingrid Fagerström Kristensen, Lars Stenberg, Sara Kinhult, Hunor Benedek, Simon Ek, Svend Aage Engelholm, Silke Engelholm, Per Munck af Rosenschöld
In this retrospective cohort study all adult patients with grade 2–3 gliomas that were planned for radiotherapy at the Department of Oncology at Skåne University Hospital from May 2012 to December 2019 were included. The patients were scanned and delineated at Skåne University Hospital, and subsequently received either PT at the Skandion Clinic, Uppsala during 2016–2019 or XRT at Skåne University Hospital during 2012–2019. The patients were followed up until March 31, 2021. In this study, we included patients several years before the introduction of proton therapy. In this way, patients with favorable clinical prognostic factors who were treated using both XRT and PT were studied and included in the multivariate analysis. Thus, we hope to reveal any differences related to the therapy rather than intrinsic bias in the selection of PT patients. We followed the EQUATOR guidelines for reporting, using the STROBE checklist for observational studies (checklist included in the Supplementary File) [16]. The study was approved by the Swedish Ethical Review Authority (2020-04164).
Proton therapy for early breast cancer patients in the DBCG proton trial: planning, adaptation, and clinical experience from the first 43 patients
Published in Acta Oncologica, 2022
Maria Fuglsang Jensen, Line Bjerregaard Stick, Morten Høyer, Camilla Jensenius Skovhus Kronborg, Ebbe Laugaard Lorenzen, Hanna Rahbek Mortensen, Petra Witt Nyström, Stine Elleberg Petersen, Pia Randers, Linh My Hoang Thai, Esben Svitzer Yates, Birgitte Vrou Offersen
Radiation therapy (RT) of early breast cancer reduces the risk of local, regional and distant failure, and for selected patients it improves overall survival [1,2]. RT is the standard treatment following breast conserving surgery (BCS) and for all high-risk patients, which in most countries are defined by having minimum one regional node macro-metastasis or a tumor larger than 50 mm. The majority of these patients receives target coverage and low dose to organs at risk (OAR) with photon RT using conventional tangential field arrangements. This technique has many practical advantages such as high robustness toward shrinkage, swelling and other smaller day-to-day variations. However, for some anatomies, it can be challenging to provide adequate target coverage without a high dose to the heart, lung or contralateral breast despite treatment in deep inspiration breath-hold. This is especially seen when the internal mammary nodes (IMN) are a target and for these patients, a coverage compromise is often made to achieve a lower dose to heart and lung [3]. These high-risk patients may be the best candidates for proton therapy and several comparative treatment planning studies have shown that protons can provide full target coverage and a low dose to the heart and lung for all anatomies [4–7]. Indeed, proton therapy has been introduced for selected breast cancer patients in several proton centers across the world [8–14] and randomized clinical trials are currently enrolling patients to clarify benefits and risks and refine selection criteria for future standard use of proton therapy for breast cancer patients [15,16].