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Journal of Medical Radiation Sciences Mar 2021A transparent and equitable process for selecting patients who will benefit most from treatment at the Australian Bragg Centre for Proton Therapy as well as providing...
A transparent and equitable process for selecting patients who will benefit most from treatment at the Australian Bragg Centre for Proton Therapy as well as providing cost benefit for the investment made by government for this valuable resource, needs to be in place as soon as the Centre becomes operational, particularly for patients with more common cancers. Markov modelling is one method of patient selection and an example is provided in this issue of the Journal of Medical Radiation Sciences.
Topics: Cost-Benefit Analysis; Humans; Patient Selection; Proton Therapy
PubMed: 33259660
DOI: 10.1002/jmrs.454 -
The British Journal of Radiology Mar 2020
Topics: Humans; Neoplasms; Proton Therapy
PubMed: 32081045
DOI: 10.1259/bjr.20209004 -
World Journal of Gastroenterology Jul 2018Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death, as few patients can be treated with currently available curative local modalities. In... (Review)
Review
Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death, as few patients can be treated with currently available curative local modalities. In patients with HCC where curative modalities are not feasible, radiation therapy (RT) has emerged as an alternative or combination therapy. With the development of various technologies, RT has been increasingly used for the management of HCC. Among these advances, proton beam therapy (PBT) has several unique physical properties that give it a finite range in a distal direction, and thus no exit dose along the beam path. Therefore, PBT has dosimetric advantages compared with X-ray therapy for the treatment of HCC. Indeed, various reports in the literature have described the favorable clinical outcomes and improved safety of PBT for HCC patients compared with X-ray therapy. However, there are some technical issues regarding the use of PBT in HCC, including uncertainty of organ motion and inaccuracy during calculation of tissue density and beam range, all of which may reduce the robustness of a PBT treatment plan. In this review, we discuss the physical properties, current clinical data, technical issues, and future perspectives on PBT for the treatment of HCC.
Topics: Carcinoma, Hepatocellular; DNA Damage; Digestive System; Humans; Liver Neoplasms; Proton Therapy; Radiation Injuries; Radiometry; Radiotherapy Dosage; Treatment Outcome
PubMed: 30065555
DOI: 10.3748/wjg.v24.i28.3090 -
Scientific Reports May 2022The objective of this study was to improve the precision of linear energy transfer (LET) measurements using [Formula: see text] optically stimulated luminescence...
The objective of this study was to improve the precision of linear energy transfer (LET) measurements using [Formula: see text] optically stimulated luminescence detectors (OSLDs) in proton beams, and, with that, improve OSL dosimetry by correcting the readout for the LET-dependent ionization quenching. The OSLDs were irradiated in spot-scanning proton beams at different doses for fluence-averaged LET values in the (0.4-6.5) [Formula: see text] range (in water). A commercial automated OSL reader with a built-in beta source was used for the readouts, which enabled a reference irradiation and readout of each OSLD to establish individual corrections. Pulsed OSL was used to separately measure the blue (F-center) and UV ([Formula: see text]-center) emission bands of [Formula: see text] and the ratio between them (UV/blue signal) was used for the LET measurements. The average deviation between the simulated and measured LET values along the central beam axis amounts to 5.5% if both the dose and LET are varied, but the average deviation is reduced to 3.5% if the OSLDs are irradiated with the same doses. With the measurement procedure and automated equipment used here, the variation in the signals used for LET estimates and quenching-corrections is reduced from 0.9 to 0.6%. The quenching-corrected OSLD doses are in agreement with ionization chamber measurements within the uncertainties. The automated OSLD corrections are demonstrated to improve the LET estimates and the ionization quenching-corrections in proton dosimetry for a clinically relevant energy range up to 230 MeV. It is also for the first time demonstrated how the LET can be estimated for different doses.
Topics: Linear Energy Transfer; Luminescence; Proton Therapy; Protons; Radiometry
PubMed: 35585205
DOI: 10.1038/s41598-022-10575-4 -
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 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 -
Current Treatment Options in Oncology Jun 2021The rise in the incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPC), the relatively young age at which it is diagnosed, and... (Review)
Review
The rise in the incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPC), the relatively young age at which it is diagnosed, and its favorable prognosis necessitate the use of treatment techniques that reduce the likelihood of side effects during and after curative treatment. Intensity-modulated proton therapy (IMPT) is a form of radiotherapy that de-intensifies treatment through dose de-escalation to normal tissues without compromising dose to the primary tumor and involved, regional lymph nodes. Preclinical studies have demonstrated that HPV-positive squamous cell carcinoma is more sensitive to proton radiation than is HPV-negative squamous cell carcinoma. Retrospective studies comparing intensity-modulated photon (X-ray) radiotherapy to IMPT for OPC suggest comparable rates of disease control and lower rates of pain, xerostomia, dysphagia, dysgeusia, gastrostomy tube dependence, and osteoradionecrosis with IMPT-all of which meaningfully affect the quality of life of patients treated for HPV-associated OPC. Two phase III trials currently underway-the "Randomized Trial of IMPT versus IMRT for the Treatment of Oropharyngeal Cancer of the Head and Neck" and the "TOxicity Reduction using Proton bEam therapy for Oropharyngeal cancer (TORPEdO)" trial-are expected to provide prospective, level I evidence regarding the effectiveness of IMPT for such patients.
Topics: Alphapapillomavirus; Humans; Oropharyngeal Neoplasms; Papillomavirus Infections; Proton Therapy; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated; Randomized Controlled Trials as Topic; Squamous Cell Carcinoma of Head and Neck
PubMed: 34086150
DOI: 10.1007/s11864-021-00847-y -
Radiotherapy and Oncology : Journal of... Mar 2022With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of...
BACKGROUND AND PURPOSE
With high survival rates for pediatric Hodgkin lymphoma (HL), attention has turned to minimizing treatment-related morbidity and mortality. Chemotherapy and dose of radiation to organs at risk (OARs) contribute to elevated risks of secondary malignancy and cardiopulmonary disease. We sought to characterize the radiation dose to OARs, toxicities, and outcomes for pediatric HL patients treated with proton therapy (PT).
MATERIALS AND METHODS
Fifty patients aged 11-21 with HL consecutively treated with PT were evaluated 1-2 months following completion of PT and every 6 months thereafter. Acute and late toxicities were captured retrospectively using CTCAE v5. Patterns of relapse were characterized, and survival was assessed using Kaplan-Meier method.
RESULTS
Most (47, 94%) patients received PT to the mediastinum. Median mean heart dose was 4.3 Gy (RBE) and median bilateral lung V20Gy was 5.8%. Median integral dose was 1.7 Gy. For the 27 female patients, a median mean dose of 0.4 and 0.3 Gy (RBE) was delivered to ipsilateral and contralateral breast tissue, respectively. No on-treatment grade 3-5 toxicities were seen. At a median follow-up of 5.3 years, no PT-related grade 3-5 toxicities or secondary malignancies developed. Five patients relapsed at a median time of 9.2 months after PT (range 2.5-24.9 months; 5-year recurrence free survival 90%). Recurrences were both in- and out-of-field in all 5 cases with no marginal failures. All relapsed patients were successfully salvaged (5-year overall survival 100%).
CONCLUSION
For pediatric HL patients, proton treatment resulted in marked dose sparing of OARs with low rates of toxicity, no marginal failures, and excellent 5-year survival.
Topics: Adolescent; Adult; Child; Female; Hodgkin Disease; Humans; Neoplasm Recurrence, Local; Organs at Risk; Proton Therapy; Radiotherapy Dosage; Retrospective Studies; Young Adult
PubMed: 35101461
DOI: 10.1016/j.radonc.2022.01.016 -
International Journal of Radiation... Nov 2023Adjuvant proton beam therapy (PBT) is increasingly available to patients with breast cancer. It achieves better planned dose distributions than standard photon radiation... (Meta-Analysis)
Meta-Analysis
PURPOSE
Adjuvant proton beam therapy (PBT) is increasingly available to patients with breast cancer. It achieves better planned dose distributions than standard photon radiation therapy and therefore may reduce the risks. However, clinical evidence is lacking.
METHODS AND MATERIALS
A systematic review of clinical outcomes from studies of adjuvant PBT for early breast cancer published in 2000 to 2022 was undertaken. Early breast cancer was defined as when all detected invasive cancer cells are in the breast or nearby lymph nodes and can be removed surgically. Adverse outcomes were summarized quantitatively, and the prevalence of the most common ones were estimated using meta-analysis.
RESULTS
Thirty-two studies (1452 patients) reported clinical outcomes after adjuvant PBT for early breast cancer. Median follow-up ranged from 2 to 59 months. There were no published randomized trials comparing PBT with photon radiation therapy. Scattering PBT was delivered in 7 studies (258 patients) starting 2003 to 2015 and scanning PBT in 22 studies (1041 patients) starting 2000 to 2019. Two studies (123 patients) starting 2011 used both PBT types. For 1 study (30 patients), PBT type was unspecified. Adverse events were less severe after scanning than after scattering PBT. They also varied by clinical target. For partial breast PBT, 498 adverse events were reported (8 studies, 358 patients). None were categorized as severe after scanning PBT. For whole breast or chest wall ± regional lymph nodes PBT, 1344 adverse events were reported (19 studies, 933 patients). After scanning PBT, 4% (44/1026) of events were severe. The most prevalent severe outcome after scanning PBT was dermatitis, which occurred in 5.7% (95% confidence interval, 4.2-7.6) of patients. Other severe adverse outcomes included infection, pain, and pneumonitis (each ≤1%). Of the 141 reconstruction events reported (13 studies, 459 patients), the most prevalent after scanning PBT was prosthetic implant removal (34/181, 19%).
CONCLUSIONS
This is a quantitative summary of all published clinical outcomes after adjuvant PBT for early breast cancer. Ongoing randomized trials will provide information on its longer-term safety compared with standard photon radiation therapy.
Topics: Humans; Female; Breast Neoplasms; Proton Therapy
PubMed: 36868521
DOI: 10.1016/j.ijrobp.2023.02.023 -
Sovremennye Tekhnologii V Meditsine 2021Proton therapy (PT) due to dosimetric characteristics (Bragg peak formation, sharp dose slowdown) is currently one of the most high-tech techniques of radiation therapy... (Review)
Review
Proton therapy (PT) due to dosimetric characteristics (Bragg peak formation, sharp dose slowdown) is currently one of the most high-tech techniques of radiation therapy exceeding the standards of photon methods. In recent decades, PT has traditionally been used, primarily, for head and neck cancers (HNC) including skull base tumors. Regardless of the fact that recently PT application area has significantly expanded, HNC still remain a leading indication for proton radiation since PT's physic-dosimetric and radiobiological advantages enable to achieve the best treatment results in these tumors. The present review is devoted to PT usage in HNC treatment in the world and Russian medicine, the prospects for further technique development, the assessment of PT's radiobiological features, a physical and dosimetric comparison of protons photons distribution. The paper shows PT's capabilities in the treatment of skull base tumors, HNC (nasal cavity, paranasal sinuses, nasopharynx, oropharynx, and laryngopharynx, etc.), eye tumors, sialomas. The authors analyze the studies on repeated radiation and provide recent experimental data on favorable profile of proton radiation compared to the conventional radiation therapy. The review enables to conclude that currently PT is a dynamic radiation technique opening up new opportunities for improving therapy of oncology patients, especially those with HNC.
Topics: Head and Neck Neoplasms; Humans; Photons; Proton Therapy; Radiometry; Skull Base Neoplasms
PubMed: 34603766
DOI: 10.17691/stm2021.13.4.08