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Journal of Magnetic Resonance Imaging :... Dec 2018Advances in multimodality imaging, providing accurate information of the irradiated target volume and the adjacent critical structures or organs at risk (OAR), has made... (Review)
Review
Advances in multimodality imaging, providing accurate information of the irradiated target volume and the adjacent critical structures or organs at risk (OAR), has made significant improvements in delivery of the external beam radiation dose. Radiation therapy conventionally has used computed tomography (CT) imaging for treatment planning and dose delivery. However, magnetic resonance imaging (MRI) provides unique advantages: added contrast information that can improve segmentation of the areas of interest, motion information that can help to better target and deliver radiation therapy, and posttreatment outcome analysis to better understand the biologic effect of radiation. To take advantage of these and other potential advantages of MRI in radiation therapy, radiologists and MRI physicists will need to understand the current radiation therapy workflow and speak the same language as our radiation therapy colleagues. This review article highlights the emerging role of MRI in radiation dose planning and delivery, but more so for MR-only treatment planning and delivery. Some of the areas of interest and challenges in implementing MRI in radiation therapy workflow are also briefly discussed. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;48:1468-1478.
Topics: Humans; Immobilization; Magnetic Resonance Imaging; Multimodal Imaging; Neoplasms; Perfusion; Radiation Oncology; Radiotherapy; Radiotherapy Planning, Computer-Assisted; Tomography, X-Ray Computed
PubMed: 30194794
DOI: 10.1002/jmri.26271 -
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 -
Journal of Radiation Research Jun 2023Japanese national oncological experts convened to evaluate the efficacy and safety of particle beam therapy (PT) for pulmonary, liver and lymph node oligometastases...
Comprehensive analysis of Japanese nationwide cohort data of particle beam therapy for pulmonary, liver and lymph node oligometastases: particle beam therapy versus high-precision X-ray radiotherapy.
Japanese national oncological experts convened to evaluate the efficacy and safety of particle beam therapy (PT) for pulmonary, liver and lymph node oligometastases (P-OM, L-OM and LN-OM, respectively) and to conduct a statistically comparative analysis of the local control (LC) rate and overall survival (OS) rate of PT versus those of X-ray stereotactic body radiotherapy (X-SBRT) and X-ray intensity-modulated radiotherapy (X-IMRT). They conducted [1] an analysis of the efficacy and safety of metastasis-directed therapy with PT for P-OM, L-OM and LN-OM using a Japanese nationwide multi-institutional cohort study data set; [2] a systematic review of X-ray high-precision radiotherapy (i.e. X-SBRT/X-IMRT) and PT for P-OM, L-OM and LN-OM; and [3] a statistical comparison between LC and OS of the cohort data set in PT and that of the extracted historical data set in X-SBRT/X-IMRT from the preceding systematic review. Safety was evaluated as the incidence of grade ≥ 3 adverse events, while statistical comparisons of LC and OS were conducted by estimating the incidence rate ratios (IRR) for local progression and mortality, respectively. This study demonstrated that PT provided durable LC (3-year LC rate: 72.8-83.2%) with acceptable OS (3-year OS rate: 38.5-68.1%) and risk of severe toxicity incidence of 0.8-3.5% in radical metastasis-directed therapy for P-OM, L-OM and LN-OM. Compared to LC with X-SBRT or X-IMRT, LC with PT was potentially superior for P-OM; superior for L-OM; and equivalent for LN-OM. In particular, this study demonstrated that PT may be a new treatment option for L-OM tumors measuring > 5 cm.
Topics: Humans; Cohort Studies; East Asian People; Liver; Radiosurgery; Retrospective Studies; Treatment Outcome; X-Rays; Neoplasm Metastasis
PubMed: 37053162
DOI: 10.1093/jrr/rrad004 -
The British Journal of Radiology Mar 2020Radiation therapy is an essential component of treatment for locally advanced non-small cell lung cancer (NSCLC) but can be technically challenging because of the... (Review)
Review
Radiation therapy is an essential component of treatment for locally advanced non-small cell lung cancer (NSCLC) but can be technically challenging because of the proximity of lung tumors to nearby critical organs or structures. The most effective strategy for reducing radiation-induced toxicity is to reduce unnecessary exposure of normal tissues by using advanced technology; examples from photon (X-ray) therapy have included three-dimensional conformal radiation therapy versus its predecessor, two-dimensional radiation therapy, and intensity-modulated photon radiation therapy versus its predecessor, three-dimensional conformal therapy. Using particle-beam therapy rather than photons offers the potential for further advantages because of the unique depth-dose characteristics of the particles, which can be exploited to allow still higher dose escalation to tumors with greater sparing of normal tissues, with the ultimate goal of improving local tumor control and survival while preserving quality of life by reducing treatment-related toxicity. However, the costs associated with particle therapy with protons are considerably higher than the current state of the art in photon technology, and evidence of clinical benefit from protons is increasingly being demanded to justify the higher financial burden on the healthcare system. Some such evidence is available from preclinical studies, from retrospective, single-institution clinical series, from analyses of national databases, and from single-arm prospective studies in addition to several ongoing randomized comparative trials. This review summarizes the rationale for and challenges of using proton therapy to treat thoracic cancers, reviews the current clinical experience, and suggests topics for future research.
Topics: Carcinoma, Non-Small-Cell Lung; Forecasting; Humans; Lung Neoplasms; Organ Sparing Treatments; Organs at Risk; Prospective Studies; Proton Therapy; Quality of Life; Radiation Injuries; Radiotherapy, Conformal; Radiotherapy, Intensity-Modulated; Randomized Controlled Trials as Topic; Retrospective Studies; Treatment Outcome
PubMed: 31430188
DOI: 10.1259/bjr.20190378 -
International Journal of Radiation... Mar 2022This study provides the first experimental application of multiscale 3-dimensional (3D) x-ray phase contrast imaging computed tomography (XPCI-CT) virtual histology for...
PURPOSE
This study provides the first experimental application of multiscale 3-dimensional (3D) x-ray phase contrast imaging computed tomography (XPCI-CT) virtual histology for the inspection and quantitative assessment of the late-stage effects of radio-induced lesions on lungs in a small animal model.
METHODS AND MATERIALS
Healthy male Fischer rats were irradiated with x-ray standard broad beams and microbeam radiation therapy, a high-dose rate (14 kGy/s), FLASH spatially fractionated x-ray therapy to avoid beamlet smearing owing to cardiosynchronous movements of the organs during the irradiation. After organ dissection, ex vivo XPCI-CT was applied to all the samples and the results were quantitatively analyzed and correlated to histologic data.
RESULTS
XPCI-CT enables the 3D visualization of lung tissues with unprecedented contrast and sensitivity, allowing alveoli, vessel, and bronchi hierarchical visualization. XPCI-CT discriminates in 3D radio-induced lesions such as fibrotic scars and Ca/Fe deposits and allows full-organ accurate quantification of the fibrotic tissue within the irradiated organs. The radiation-induced fibrotic tissue content is less than 10% of the analyzed volume for all microbeam radiation therapy-treated organs and reaches 34% in the case of irradiations with 50 Gy using a broad beam.
CONCLUSIONS
XPCI-CT is an effective imaging technique able to provide detailed 3D information for the assessment of lung pathology and treatment efficacy in a small animal model.
Topics: Animals; Lung; Male; Rats; Tomography, X-Ray Computed; X-Ray Therapy; X-Rays
PubMed: 34678432
DOI: 10.1016/j.ijrobp.2021.10.009 -
Seminars in Radiation Oncology Apr 2021The dosimetric advantages of particle therapy lead to significantly reduced integral dose to normal tissues, making it an attractive treatment option for body sites such... (Review)
Review
The dosimetric advantages of particle therapy lead to significantly reduced integral dose to normal tissues, making it an attractive treatment option for body sites such as the thorax. With reduced normal tissue dose comes the potential for dose escalation, toxicity reduction, or hypofractionation. While proton and heavy ion therapy have been used extensively for NSCLC, there are challenges in planning and delivery compared with X-ray-based radiation therapy. Particularly, range uncertainties compounded by breathing motion have to be considered. This article summarizes the current state of particle therapy for NSCLC with a specific focus on the impact of dosimetric uncertainties in planning and delivery.
Topics: Carcinoma, Non-Small-Cell Lung; Humans; Lung Neoplasms; Physics; Proton Therapy; Radiotherapy Planning, Computer-Assisted
PubMed: 33610274
DOI: 10.1016/j.semradonc.2020.11.004 -
The British Journal of Radiology Jan 2021Coronavirus disease 19 (Covid-19) poses a huge threat to health systems and economies worldwide. So far, there has been no proven effective treatment for SARS-CoV-2...
Coronavirus disease 19 (Covid-19) poses a huge threat to health systems and economies worldwide. So far, there has been no proven effective treatment for SARS-CoV-2 infection. Various potential therapies, viz., immunomodulatory agents, antiviral therapy, and plasma transfusion, are undergoing clinical trials. An intensive search of the medical corpora revealed that low dose X-ray radiation therapy has been used in the past to treat interstitial pneumonia. In this article we explore a historical background of low-dose X-rays for the treatment of pneumonia and how it could be a promising therapy in treating patients with COVID-19.
Topics: COVID-19; History, 20th Century; Humans; Radiotherapy Dosage; X-Ray Therapy
PubMed: 33252988
DOI: 10.1259/bjr.20200581 -
Medical Physics Jun 2022Microbeam radiation therapy (MRT) is a treatment modality based on spatial fractionation of synchrotron generated X-rays into parallel, high dose, microbeams of a few...
BACKGROUND
Microbeam radiation therapy (MRT) is a treatment modality based on spatial fractionation of synchrotron generated X-rays into parallel, high dose, microbeams of a few microns width. MRT is still an underdevelopment radiosurgery technique for which, promising preclinical results on brain tumors and epilepsy encourages its clinical transfer.
PURPOSE
A safe clinical transfer of MRT needs a specific treatment planning system (TPS) that provides accurate dose calculations in human patients, taking into account the MRT beam's properties (high-dose gradients, spatial fractionation, polarization effects). So far, the most advanced MRT TPS, based on a hybrid dose calculation algorithm, is limited to a macroscopic rendering of the dose and does not account for the complex dose distribution inherent to MRT if delivered as conformal irradiations with multiple incidences. For overcoming these limitations, a multi-scale full Monte-Carlo calculation engine called penMRT has been developed and benchmarked against two general-purpose Monte Carlo (MC) codes: penmain based on PENELOPE and Gate based on Geant4.
METHODS
PenMRT, is based on the PENELOPE (2018) MC code, modified to take into account the voxelized geometry of the patients (computed tomography [CT]-scans) and is offering an adaptive micrometric dose calculation grid independent of the CT size, location, and orientation. The implementation of the dynamic memory allocation in penMRT, makes the simulations feasible within a huge number of dose scoring bins. The possibility of using a source replication approach to simulate arrays of microbeams, and the parallelization using OpenMPI have been added to penMRT in order to increase the calculation speed for clinical usages. This engine can be implemented in a TPS as a dose calculation core.
RESULTS
The performance tests highlight the reliability of penMRT to be used for complex irradiation conditions in MRT. The benchmarking against a standard PENELOPE code did not show any significant difference for calculations in centimetric beams, for a single microbeam and for a microbeam array. The comparisons between penMRT and Gate as an independent MC code did not show any difference in the beam paths, whereas, in valley regions, relative differences between the two codes rank from 1% to 7.5% which are probably due to the differences in physics lists that are used in these two codes. The reliability of the source replication approach has also been tested and validated with an underestimation of no more than 0.6% in low-dose areas.
CONCLUSIONS
Good agreements (a relative difference between 0% and 8%) were found when comparing calculated peak to valley dose ratio values using penMRT, for irradiations with a full microbeam array, with calculated values in the literature. The high-resolution calculated dose maps obtained with penMRT are used to extract differential and cumulative dose-volume histograms (DVHs) and analyze treatment plans with much finer metrics regarding the irradiation complexity. To our knowledge, these are the first high-resolution dose maps and associated DVHs ever obtained for cross-fired microbeams irradiation, which is bringing a significant added value to the field of treatment planning in spatially fractionated radiation therapy.
Topics: Humans; Monte Carlo Method; Radiotherapy Dosage; Radiotherapy Planning, Computer-Assisted; Reproducibility of Results; Synchrotrons; X-Ray Therapy; X-Rays
PubMed: 35342953
DOI: 10.1002/mp.15637 -
Clinical and Molecular Hepatology Oct 2023Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death, and external beam radiation therapy has emerged as a promising approach for managing HCC.... (Review)
Review
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death, and external beam radiation therapy has emerged as a promising approach for managing HCC. Proton beam therapy (PBT) offers dosimetric advantages over X-ray therapy, with superior physical properties known as the Bragg peak. PBT holds promise for reducing hepatotoxicity and allowing safe dose-escalation to the tumor. It has been tried in various clinical conditions and has shown promising local tumor control and survival outcomes. A recent phase III trial demonstrated the non-inferiority of PBT in local tumor control compared to current standard radiofrequency ablation in early-stage HCC. PBT also tended to show more favorable outcomes compared to transarterial chemoembolization in the intermediate stage, and has proven effective in-field disease control and safe toxicity profiles in advanced HCC. In this review, we discuss the rationale, clinical studies, optimal indication, and future directions of PBT in HCC treatment.
Topics: Humans; Carcinoma, Hepatocellular; Proton Therapy; Liver Neoplasms; Chemoembolization, Therapeutic
PubMed: 37822213
DOI: 10.3350/cmh.2023.0274 -
Journal of Medical Radiation Sciences Mar 2022The aim was to explore various national and international clinical decision-making tools and dose comparison methods used for selecting cancer patients for proton versus... (Review)
Review
The aim was to explore various national and international clinical decision-making tools and dose comparison methods used for selecting cancer patients for proton versus X-ray radiation therapy. To address this aim, a literature search using defined scoping review methods was performed in Medline and Embase databases as well as grey literature. Articles published between 1 January 2015 and 4 August 2020 and those that clearly stated methods of proton versus X-ray therapy patient selection and those published in English were eligible for inclusion. In total, 321 studies were identified of which 49 articles met the study's inclusion criteria representing 13 countries. Six different clinical decision-making tools and 14 dose comparison methods were identified, demonstrating variability within countries and internationally. Proton therapy was indicated for all paediatric patients except those with lymphoma and re-irradiation where individualised model-based selection was required. The most commonly reported patient selection tools included the Normal Tissue Complication Probability model, followed by cost-effectiveness modelling and dosimetry comparison. Model-based selection methods were most commonly applied for head and neck clinical indications in adult cohorts (48% of studies). While no 'Gold Standard' currently exists for proton therapy patient selection with variations evidenced globally, some of the patient selection methods identified in this review can be used to inform future practice in Australia. As literature was not identified from all countries where proton therapy centres are available, further research is needed to evaluate patient selection methods in these jurisdictions for a comprehensive overview.
Topics: Adult; Child; Cost-Benefit Analysis; Humans; Neoplasms; Patient Selection; Probability; Proton Therapy
PubMed: 34476905
DOI: 10.1002/jmrs.540