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Chinese Clinical Oncology Aug 2016Relative to conventional photon irradiation, proton therapy has distinct advantages in its ability to more precisely target tumor while shielding adjacent normal... (Review)
Review
Relative to conventional photon irradiation, proton therapy has distinct advantages in its ability to more precisely target tumor while shielding adjacent normal tissues. In the setting of skull base tumors, proton therapy plays a critical role in the dose-escalation required for optimal tumor control of chordomas, chondrosarcomas, and malignancies of the paranasal sinuses and nasal cavity. For benign tumors such as craniopharyngiomas, pituitary adenomas and meningiomas, proton therapy can limit long-term adverse effects, such as secondary malignancies. This review summarizes published literature to date regarding the role of proton therapy in skull base tumors and introduces emerging proton therapy approaches such as pencil-beam scanning (PBS).
Topics: Humans; Proton Therapy; Skull; Skull Base Neoplasms
PubMed: 27558252
DOI: 10.21037/cco.2016.07.05 -
International Journal of Radiation... Oct 2017Considering the clinical potential of protons attributable to their physical characteristics, interest in proton therapy has increased greatly in this century, as has... (Review)
Review
Considering the clinical potential of protons attributable to their physical characteristics, interest in proton therapy has increased greatly in this century, as has the number of proton therapy installations. Until recently, passively scattered proton therapy was used almost entirely. Notably, the overall clinical results to date have not shown a convincing benefit of protons over photons. A rapid transition is now occurring with the implementation of the most advanced form of proton therapy, intensity modulated proton therapy (IMPT). IMPT is superior to passively scattered proton therapy and intensity modulated radiation therapy (IMRT) dosimetrically. However, numerous limitations exist in the present IMPT methods. In particular, compared with IMRT, IMPT is highly vulnerable to various uncertainties. In this overview we identify three major areas of current limitations of IMPT: treatment planning, treatment delivery, and motion management, and discuss current and future efforts for improvement. For treatment planning, we need to reduce uncertainties in proton range and in computed dose distributions, improve robust planning and optimization, enhance adaptive treatment planning and delivery, and consider how to exploit the variability in the relative biological effectiveness of protons for clinical benefit. The quality of proton therapy also depends on the characteristics of the IMPT delivery systems and image guidance. Efforts are needed to optimize the beamlet spot size for both improved dose conformality and faster delivery. For the latter, faster energy switching time and increased dose rate are also needed. Real-time in-room volumetric imaging for guiding IMPT is in its early stages with cone beam computed tomography (CT) and CT-on-rails, and continued improvements are anticipated. In addition, imaging of the proton beams themselves, using, for instance, prompt γ emissions, is being developed to determine the proton range and to reduce range uncertainty. With the realization of the advances described above, we posit that IMPT, thus empowered, will lead to substantially improved clinical results.
Topics: Health Physics; Humans; Linear Energy Transfer; Movement; Neoplasms; Proton Therapy; Quality of Health Care; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Image-Guided; Radiotherapy, Intensity-Modulated; Relative Biological Effectiveness; Respiration; Technology, Radiologic; Uncertainty
PubMed: 28871980
DOI: 10.1016/j.ijrobp.2017.05.005 -
The British Journal of Radiology Mar 2019Extraordinary normal tissue response to highly spatially fractionated X-ray beams has been explored for over 25 years. More recently, alternative radiation sources have... (Review)
Review
Extraordinary normal tissue response to highly spatially fractionated X-ray beams has been explored for over 25 years. More recently, alternative radiation sources have been developed and utilized with the aim to evoke comparable effects. These include protons, which lend themselves well for this endeavour due to their physical depth dose characteristics as well as corresponding variable biological effectiveness. This paper addresses the motivation for using protons to generate spatially fractionated beams and reviews the technological implementations and experimental results to date. This includes simulation and feasibility studies, collimation and beam characteristics, dosimetry and biological considerations as well as the results of in vivo and in vitro studies. Experimental results are emerging indicating an extraordinary normal tissue sparing effect analogous to what has been observed for synchrotron generated X-ray microbeams. The potential for translational research and feasibility of spatially modulated proton beams in clinical settings is discussed.
Topics: Animals; Dose Fractionation, Radiation; Humans; Proton Therapy; Radiometry; Radiotherapy Dosage
PubMed: 30359081
DOI: 10.1259/bjr.20180466 -
The British Journal of Radiology Mar 2020Proton therapy has shown dosimetric advantages over conventional radiation therapy using photons. Although the integral dose for patients treated with proton therapy is... (Review)
Review
Proton therapy has shown dosimetric advantages over conventional radiation therapy using photons. Although the integral dose for patients treated with proton therapy is low, concerns were raised about late effects like secondary cancer caused by dose depositions far away from the treated area. This is especially true for neutrons and therefore the stray dose contribution from neutrons in proton therapy is still being investigated. The higher biological effectiveness of neutrons compared to photons is the main cause of these concerns. The gold-standard in neutron dosimetry is measurements, but performing neutron measurements is challenging. Different approaches have been taken to overcome these difficulties, for instance with newly developed neutron detectors. Monte Carlo simulations is another common technique to assess the dose from secondary neutrons. Measurements and simulations are used to develop analytical models for fast neutron dose estimations. This article tries to summarize the developments in the different aspects of neutron dose in proton therapy since 2017. In general, low neutron doses have been reported, especially in active proton therapy. Although the published biological effectiveness of neutrons relative to photons regarding cancer induction is higher, it is unlikely that the neutron dose has a large impact on the second cancer risk of proton therapy patients.
Topics: Humans; Monte Carlo Method; Neoplasms, Radiation-Induced; Neoplasms, Second Primary; Neutrons; Photons; Proton Therapy; Radiometry; Radiotherapy Dosage; Relative Biological Effectiveness
PubMed: 31868525
DOI: 10.1259/bjr.20190412 -
Seminars in Oncology Jun 2019Treatment of cancer patients with charged particles like proton and carbon ions landmarks a new era in high-precision medicine. This review aims to summarize the... (Review)
Review
Treatment of cancer patients with charged particles like proton and carbon ions landmarks a new era in high-precision medicine. This review aims to summarize the physical and biological advantages of charged particle beams over conventional photon irradiation, presents some highlights in the treatment of selected tumor entities, and gives an update on previous and ongoing clinical trials.
Topics: Clinical Trials as Topic; Heavy Ion Radiotherapy; Humans; Neoplasms; Proton Therapy
PubMed: 31451309
DOI: 10.1053/j.seminoncol.2019.07.005 -
Practical Radiation Oncology 2024This work aims at reviewing challenges and pitfalls in proton facility design related to equipment upgrade or replacement. Proton therapy was initially developed at... (Review)
Review
PURPOSE
This work aims at reviewing challenges and pitfalls in proton facility design related to equipment upgrade or replacement. Proton therapy was initially developed at research institutions in the 1950s which ushered in the use of hospital-based machines in 1990s. We are approaching an era where older commercial machines are reaching the end of their life and require replacement. The future widespread application of proton therapy depends on cost reduction; customized building design and installation are significant expenses.
METHODS AND MATERIALS
We take this opportunity to discuss how commercial proton machines have been installed and how buildings housing the equipment have been designed.
RESULTS
Data on dimensions and weights of the larger components of proton systems (cyclotron main magnet and gantries) are presented and innovative, non-gantry-based, patient positioning systems are discussed.
CONCLUSIONS
We argue that careful consideration of the building design to include larger elevators, hoistways from above, wide corridors and access slopes to below grade installations, generic vault and treatment room layouts to accommodate multiple vendor's equipment, and modular system design can provide specific benefits during planning, installation, maintenance, and replacement phases of the project. Room temperature magnet coils can be constructed in a more modular manner: a potential configuration is presented. There is scope for constructing gantries and magnet yokes from smaller modular sub-units. These considerations would allow a hospital to replace a commercial machine at its end of life in a manner similar to a linac.
Topics: Proton Therapy; Humans; Facility Design and Construction; Equipment Design
PubMed: 37967747
DOI: 10.1016/j.prro.2023.09.011 -
British Journal of Hospital Medicine... Oct 2019Radiotherapy is a highly effective anti-cancer treatment commonly used alongside systemic therapies and surgery to achieve long-term cancer-free survival. Conventional... (Review)
Review
Radiotherapy is a highly effective anti-cancer treatment commonly used alongside systemic therapies and surgery to achieve long-term cancer-free survival. Conventional radiotherapy uses photon beams to deliver a high dose of radiation to the tumour volume to eradicate cancer cells. This has to be offset against the irradiation of surrounding normal tissues, as increasing this dose causes more treatment-related toxicity. In August 2018, the NHS's first high energy proton beam therapy centre opened at The Christie NHS Foundation Trust in Manchester. A second NHS centre is scheduled to open in 2020 at the University College London Hospitals NHS Trust. Proton beam therapy may offer dosimetric advantages compared to conventional radiotherapy as a result of its characteristic dose deposition - proton beams deliver a comparatively higher proportion of their dose to the target volume relative to normal tissues, without significant exit doses when compared to conventional photon therapy. Therefore proton beam therapy may be indicated for certain tumours situated next to critical organs or in the paediatric population where quality of life and the reduction of secondary effects from radiation are particularly significant. The indications for proton beam therapy and patient outcomes after treatment will be carefully monitored and evaluated in order to provide a robust evidence base for its use.
Topics: Diagnostic Imaging; Humans; London; Neoplasms; Proton Therapy; Quality of Life; Radiotherapy Dosage; State Medicine
PubMed: 31589515
DOI: 10.12968/hmed.2019.80.10.574 -
Cancer Journal (Sudbury, Mass.) 2014External beam radiation therapy is a commonly utilized treatment modality in the management of head and neck cancer. Given the close proximity of disease to critical... (Review)
Review
External beam radiation therapy is a commonly utilized treatment modality in the management of head and neck cancer. Given the close proximity of disease to critical normal tissues and structures, the delivery of external beam radiation therapy can result in severe acute and late toxicities, even when delivered with advanced photon-based techniques, such as intensity-modulated radiation therapy. The unique physical characteristics of protons make it a promising option in the treatment of advanced head and neck cancer, with the potential to improve sparing of normal tissues and/or safely escalate radiation doses. Clinical implementation will require the continued development of advanced techniques such as intensity-modulated proton therapy, using pencil beam scanning, as well as rigorous methods of quality assurance and adaptive techniques to accurately adjust to changes in anatomy due to disease response. Ultimately, the widespread adaptation and implementation of proton therapy for head and neck cancer will require direct, prospective comparisons to standard techniques such as intensity-modulated radiation therapy, with a focus on measures such as toxicity, disease control, and quality of life.
Topics: Chondrosarcoma; Chordoma; Head and Neck Neoplasms; Humans; Oropharyngeal Neoplasms; Papillomavirus Infections; Paranasal Sinus Neoplasms; Patient Positioning; Proton Therapy; Radiation Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Adjuvant; Skull Base Neoplasms
PubMed: 25415689
DOI: 10.1097/PPO.0000000000000077 -
Critical Reviews in Oncogenesis 2024Given the radiobiological and physical properties of the proton, proton beam therapy has the potential to be advantageous for many patients compared with conventional... (Review)
Review
Given the radiobiological and physical properties of the proton, proton beam therapy has the potential to be advantageous for many patients compared with conventional radiotherapy by limiting toxicity and improving patient outcomes in specific breast cancer scenarios.
Topics: Humans; Breast Neoplasms; Proton Therapy; Female; Protons
PubMed: 38683154
DOI: 10.1615/CritRevOncog.2023050319 -
Urologic Oncology Sep 2019Men diagnosed with localized prostate cancer have many curative treatment options including several different radiotherapeutic approaches. Proton radiation is one such... (Review)
Review
Men diagnosed with localized prostate cancer have many curative treatment options including several different radiotherapeutic approaches. Proton radiation is one such radiation treatment modality and, due to its unique physical properties, offers the appealing potential of reduced side effects without sacrificing cancer control. In this review, we examine the intriguing dosimetric rationale and theoretical benefit of proton radiation for prostate cancer and highlight the results of preclinical modeling studies. We then discuss the current state of the clinical evidence for proton efficacy and toxicity, derived from both large claim-based datasets and prospective patient-reported data. The result is that the data are mixed, and clinical equipoise persists in this area. We place these studies into context by summarizing the economics of proton therapy and the changing practice patterns of prostate proton irradiation. Finally, we await the results of a large prospective randomized clinical trial currently accruing and also a large prospective pragmatic comparative study which will provide more rigorous evidence regarding the clinical and comparative effectiveness of proton therapy for prostate cancer.
Topics: Humans; Male; Prostatic Neoplasms; Proton Therapy
PubMed: 30527342
DOI: 10.1016/j.urolonc.2018.11.012