International Workshop on Particle Therapy. Annual meeting of the EORTC Heavy Particle Therapy Group. October 28-29, 1988, Essen. Proceedings.
Explore the source record for details and available documents.
Animals↗
SEARCH · PubMed Health
Results for “particle therapy”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The role of particle therapy in the treatment of locally recurrent rectal cancer: a systematic review.
BACKGROUND: Colorectal cancer is a common malignancy. Advancements in multimodality treatment have improved outcomes. About 2-10% of patients will have a local recurrence even after optimal treatment. Salvage surgical treatment is the treatment of choice, however, in posterior and lateral recurrences, surgery is linked to a high rate of treatment-related morbidity. Some recurrences remain unresectable even after neoadjuvant treatment. MATERIALS AND METHODS: A systematic literature review was performed to search for studies on curative-intent radiation therapy (RT) with photons, stereotactic body radiation therapy (SBRT) and particle beam therapy. The aim of the literature search was to define the role of particle therapy in the treatment of patients with unresectable or inoperable local recurrences of rectal cancer where neoadjuvant treatment is unlikely to result in downstaging, leaving patients with RT as the only curative treatment option. RESULTS: 32 studies which fulfil the criteria were identified. In general, SBRT and particle beam therapy permitted the application of significantly higher doses to the target without a concomitant increase in treatment-related toxicities. CONCLUSIONS: For unresectable and inoperable locally recurrent rectal cancer ablative radiotherapy techniques such as SBRT and particle beam therapy offer a curative treatment approach as an alternative to surgery. SBRT can be offered for small local and nodal recurrences, while particle beam therapy can be offered for larger recurrences and complex shapes spanning several anatomical compartments as well. Further research is needed to stratify patients according to their need and eligibility for the different possible modalities of curative-intent RT.
Humans↗
Particle therapy and treatment of cancer.
The desire of radiation oncologists and medical physicists to maximise the radiation dose to the tumour while minimising that to healthy tissues has led to attempts to improve the dose distributions and biological effects achievable with photons and electrons. Protons, neutrons, pions, boron-neutron capture therapy, and charged-nuclei therapy (with argon, carbon, helium [alpha particles], neon, nitrogen, and silicon) have been assessed for their physical, biological, and clinical effects. In the 90 years since protons and neutrons were discovered, investigations of particle therapy for cancer have helped to elucidate many fundamental radiobiological ideas, such as linear energy transfer, relative biological effectiveness, oxygen effect, and oxygen enhancement. Particle therapy has contributed to our understanding of medical ethics when neutron therapy became intertwined with the debate over standards of informed consent in radiation experiments in humans during the cold war era. Particle teletherapy and brachytherapy continue to show promise in some clinical situations. In the future, the insights of molecular biology might clarify the ideal particles for clinical situations.
Brachytherapy↗
The promise of targeted {alpha}-particle therapy.
The use of monoclonal antibodies to deliver radioisotopes directly to tumor cells has become a promising strategy to enhance the antitumor effects of native antibodies. Since the alpha- and beta-particles emitted during the decay of radioisotopes differ in significant ways, proper selection of isotope and antibody combinations is crucial to making radioimmunotherapy a standard therapeutic modality. Because of the short pathlength (50-80 microm) and high linear energy transfer ( approximately 100 keV/microm) of alpha-emitting radioisotopes, targeted alpha-particle therapy offers the potential for more specific tumor cell killing with less damage to surrounding normal tissues than beta-emitters. These properties make targeted alpha-particle therapy ideal for the elimination of minimal residual or micrometastatic disease. Radioimmunotherapy using alpha-emitters such as (213)Bi, (211)At, and (225)Ac has shown activity in several in vitro and in vivo experimental models. Clinical trials have demonstrated the safety, feasibility, and activity of targeted alpha-particle therapy in the treatment of small-volume and cytoreduced disease. Further advances will require investigation of more potent isotopes, new sources and methods of isotope production, improved chelation techniques, better methods for pharmacokinetic and dosimetric modeling, and new methods of isotope delivery such as pretargeting. Treatment of patients with less-advanced disease and, ultimately, randomized trials comparing targeted alpha-particle therapy with standard approaches will be required to determine the clinical utility of this approach.
Alpha Particles↗
The case for particle therapy.
Among the most important decisions facing the British Government regarding the treatment of cancer in the National Health Service (NHS) is the purchase of charged particle therapy (CPT) centres. CPT is different from conventional radiotherapy: the dose is deposited far more selectively in Bragg Peaks by either protons or "heavy" ions, such as carbon. In this way, it is possible to "dose paint" targets, voxel by voxel, with far less dose to surrounding tissues than with X-ray techniques. At present the UK possesses a 62 MeV cyclotron proton facility at Clatterbridge (Wirral), which provides therapy for intraocular cancers such as melanoma; for deeper situated cancers in the pelvis, chest etc., much higher energies, over 200 MeV are required from a synchrotron facility. There is an impressive expansion in particle beam therapy (PBT) centres worldwide, since they offer good prospects of improved quality of life with enhanced cancer cures in situations where conventional therapy is limited due to radioresistance or by the close proximity of critical normal tissues. There is a threat to UK Oncology, since it is anticipated that several thousand British patients may require referral abroad for therapy; this would severely disrupt their multidisciplinary management and require demanding logistical support.
Cancer Care Facilities↗
Review and evolution of clinical results in the EORTC Heavy-Particle Therapy Group.
Part of the clinical results from the "EORTC Heavy-Particle Therapy Group" are reviewed (September 1984). Fast neutrons can bring a significant benefit, compared to conventional photon (or electron) techniques, in well defined patient series. A benefit for neutrons is observed, in Hammersmith and in Amsterdam, for locally extended salivary gland tumours. Soft tissue sarcomas can also be considered as a good indication for neutron therapy, especially when they are slowly growing and well differentiated, as shown in Essen, Hammersmith and Louvain-la-Neuve. Neutrons can bring an advantage in the treatment of some melanoma patients as shown in Hammersmith. For locally advanced prostatic carcinoma, better results for neutrons are shown in Hamburg and Louvain-la-Neuve. These data are similar to those observed in the United States from the RTOG studies. Due to a reduced differential effect between tissues after neutron treatment, irradiation of large volumes of normal tissues, at high neutron dose, should be avoided. Different possible combinations between neutrons and photons (boost, mixed schedule) are discussed.
Adenocarcinoma↗
Design of beam-modulating devices for charged-particle therapy.
The computer modeling program used to design beam-modulating devices for charged-particle therapy at Lawrence Berkeley Laboratory has been improved to allow a more realistic description of the beam. The original program used a single calculated Bragg peak to design the spread Bragg peak. The range of this curve was shifted so that Bragg curves of varying ranges could be superimposed. The new version of the program allows several measured Bragg curves with different ranges to be used as input, and interpolates between them to obtain the required data for the superposition calculation. The experimental configuration for measuring these input curves simulated therapy conditions. Seven beam-modulating propellers with spread Bragg-peak widths ranging from 2.2 to 14.4 cm were designed and constructed for a 215-MeV/u helium beam using this new design program. Depth-dose distributions produced by these new propellers were in good agreement with predicted distributions, and these propellers are currently being used clinically.
Equipment Design↗
Particle radiation therapy.
Particle radiation therapy has the potential for immediate and sustained favorable impact on management of the cancer patient by providing better local tumor control. Scientific knowledge and expertise are immediately available to mount effective clinical studies of fast neurons, protons, and helium ions, and to initiate necessary preliminary studies of pimesons and heavy ions. Meaningful studies will require a long-term commitment of support. The amount of support, although substantial, is not disproportionate to the potential benefit or existing support of other cancer research programs.
Elementary Particles↗
[Heavy particle therapy for prostate cancer].
Heavy particle (ion) beams are characterized by high relative biological effectiveness and improved dose distribution. To establish heavy ion therapy for prostate cancer, three trials have been conducted. For 247 patients with T1b-T3 cancer, carbon ion beam was irradiated 20 times/5 weeks with or without endocrine therapy. Overall and cause-specific survivals were excellent and local control was achieved in all patients except one. Grade 3 late morbidity of rectum and/or bladder/urethra was developed in 7 cases who received higher dose. Thus, total dose was decreased to 66 GyE and the radiation field was coned down during the treatment. In conclusion, carbon ion therapy is expected to exert excellent effect in the treatment of localized and locally advanced prostate cancer.
Antineoplastic Agents, Hormonal↗
Heavy-particle therapy in acromegaly and Cushing disease.
A total of 349 patients with pituitary tumors, including acromegaly, Cushing disease, Nelson syndrome, prolactin-secreting adenoma, and chromophobe adenoma, have been treated with heavy-particle radiation during the past 17 years. The incidence of side effects has been low. Only 30 patients, 8.6%, have died, most of preexisting cardiovascular complications. Heavy particle therapy provides a form of treatment with no mortality and extremely low morbidity, and its use in treating pituitary disorders has resulted in dramatic improvement in the signs and symptoms of patients with acromegaly and Cushing disease.
Acromegaly↗
[The present and future of heavy charged particle therapy].
Introduction of heavy charged particles (protons and heavy-ions) is a promising approach in cancer treatment, permitting selective irradiation to the tumor while minimizing irradiation to the surrounding normal tissues. Additionally, the efficiency of heavy-ions will be further augmented by an increased biological effectiveness caused by high-LET components. At the University of Tsukuba, treatment with 250 MeV proton beams is being performed and, unlike other facilities in the world, successful results have been obtained in the thoraco-abdominal and pelvic tumors. Heavy-ion therapy was initiated at the University of California, and in 1993 the first heavy-ion synchrotron complex dedicated to medical use in a hospital environment was completed at the National Institute of Radiological Sciences. The carbon-ion therapy was begun in June 1994 which is expected to provide optimal results in various type of tumors. A construction of heavy-ion facility is also under consideration in Germany (GSI), Austria (AUSTRON), Italy (TERA) and Japan (Hyogo prefecture).
Forecasting↗
Progress in low-LET heavy particle therapy: intracranial and paracranial tumors and uveal melanomas.
The Harvard Cyclotron Laboratory in collaboration with the Department of Radiation Medicine of the Massachusetts General Hospital and the Retina Service of the Massachusetts Eye and Ear Infirmary provides low-LET heavy particle therapy with 160 MeV protons. The improved dose distribution of protons results from their physical characteristics. A total of 965 patients have been treated as of December 31, 1984. Dose is expressed in units of cobalt gray equivalent (CGE) which is the dose in Gy multiplied by the RBE (1.1) for modulated protons relative to 60Co radiation. Sixty-seven patients with chordomas or low-grade chondrosarcomas of the base of skull or cervical spine have received proton treatment. Forty-three of these patients have been followed for at least 8 months with a median follow-up of 27 months. The median dose is 69 CGE. The 3-year actuarial local control rate is 89%. Seven patients with gliomas, eight with craniopharyngiomas, and six with meningiomas have also received proton radiation treatments. A total of 615 patients with uveal melanomas have received a median dose of 70 CGE in five fractions. Tumor regression has been seen in 94% with 66% having vision of 20/100 or better.
Actuarial Analysis↗
Hadrons in radiation therapy. Proceedings of the meeting of the European Heavy Particle Therapy Group. Orleans, France, 4-6 May 1995.
Explore the source record for details and available documents.
Animals↗
Heavy particle therapy: pituitary tumors.
Therapy with 910 MeV alpha particles provides a treatment with no mortality and an extremely low morbidity and has been highly successful in the control of pituitary hormone hypersecretion and tumor growth. It is possible to deliver radiation doses to the pituitary gland that are sufficiently high to inhibit or destroy the tumor cells that cause abnormal secretory activity without damaging the surrounding structures. The data demonstrate the effectiveness of this form of treatment in acromegaly, non-functioning pituitary tumors, prolactin secreting adenomas, Cushing's disease and Nelson's syndrome.
Acromegaly↗
Multi-layer energy filter for realizing conformal irradiation in charged particle therapy.
A new type of filter for charged particle radiotherapy is developed to reduce unwanted dose transfer to the normal tissues around a tumor. The new filter can make a static irradiation field where the width of the spread-out Bragg peak (SOBP) is two-dimensionally adjusted. That makes the field conformal to the tumor three-dimensionally. The filter is made of many layers produced by using stereolithography. The layer has a miniaturized structure that has geometrical similarity to the conventional ridge filter. Shapes of cone and pyramid are also usable for the unit-cell constructing the layer. The spread of the field in the depth direction is decided by the thickness of the filter, or by the number of layers. The experimental result of the irradiation using the ridge-type construction shows a good agreement with an estimate by the Monte Carlo calculation. By combining this technique with intensity modulation that has lateral position dependence, the conformal irradiation can be achieved by a simple procedure.
Equipment Design↗
Dosimetry intercomparisons and protocol for heavy charged particle therapy beams.
Explore the source record for details and available documents.
Canada↗
Engineered liposomes for potential alpha-particle therapy of metastatic cancer.
UNLABELLED: Disseminated, metastatic cancer is frequently incurable. Targeted alpha-particle emitters hold great promise as therapeutic agents for disseminated disease. (225)Ac is a radionuclide generator that has a 10-d half-life and results in alpha-emitting daughter elements ((221)Fr, (217)At, (213)Bi) that lead to the emission of a total of 4 alpha-particles. The aim of this study was to develop approaches for stable and controlled targeting of (225)Ac to sites of disseminated tumor metastases. Liposomes with encapsulated (225)Ac were developed to retain the potentially toxic daughters at the tumor site. METHODS: (225)Ac was passively entrapped in liposomes. To experimentally test the retention of actinium and its daughters by the liposomes, the gamma-emissions of (213)Bi were measured in liposome fractions, which were separated from the parent liposome population and the free radionuclides, at different times. Under equilibrium conditions the decay rate of (213)Bi was used to determine the concentration of (225)Ac. Measurements of the kinetics of (213)Bi activity were performed to estimate the entrapment of (213)Bi, the last alpha-emitting daughter in the decay chain. RESULTS: Stable pegylated phosphatidylcholine-cholesterol liposomes of different sizes and charge were prepared. Multiple (more than 2) (225)Ac atoms were successfully entrapped per liposome. (225)Ac retention by zwitterionic liposomes was more than 88% over 30 d. Retention by cationic liposomes was lower. A theoretical calculation showed that for satisfactory (213)Bi retention (>50%), liposomes of relatively large sizes (>650 nm in diameter) are required. (213)Bi retention was experimentally verified to be liposome-size dependent. For large liposomes, the measured (213)Bi retention was lower than theoretically predicted (less than 10%). CONCLUSION: This work supports the hypothesis that it may be possible to develop (225)Ac-based therapies by delivering multiple (225)Ac atoms in liposomes. Improvements in the retention of (225)Ac daughters will likely be necessary to fulfill this potential. Because of the size of the liposomal structures required to contain the daughters, the approach is ideally suited for locoregional therapy (e.g., intraperitoneal, intrahepatic artery, or intrathecal).
Actinium↗
Helium ion charged particle therapy for choroidal melanoma.
Nine patients with choroidal melanomas were treated with helium ion charged particle irradiation. No patient demonstrated tumor enlargement, and most lesions followed for more than five months have demonstrated tumor shrinkage. The most effective method of choroidal melanoma management is unclear. Heavy charged particle irradiation may be more applicable and have less ocular morbidity associated with it in either radioactive plaques or photocoagulation.
Adult↗