Impact of intrafraction prostate motion on clinical target coverage in proton therapy: A simulation study of dosimetric differences in two delivery techniques.

CONCLUSIONS: This study indicated that CTV dose inhomogeneity may exist for some patients with severe prostate intrafraction motion during US treatments. However, there are no statistically significant dose differences between DS and US treatment simulations. Cumulative dose of multiple-fractions significantly reduced dose uncertainties. PMID: 31478341 [PubMed - as supplied by publisher]
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research

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CONCLUSIONS: This work demonstrate the clinical acceptability of substituting MR converted RSP images instead of CT for IMPT planning of prostate cancer. This further translates into higher contouring accuracy along with lesser imaging dose. PMID: 31734604 [PubMed - as supplied by publisher]
Source: Radiotherapy and Oncology : journal of the European Society for Therapeutic Radiology and Oncology - Category: Radiology Authors: Tags: Radiother Oncol Source Type: research
This study presents the first measurements of the production of short-lived positron emitters in water, graphite, calcium and phosphorus targets irradiated with 59 MeV/u 3He and 50 MeV/u 4He beams. For these targets, the most produced short-lived nuclides are 13O/12N (T1/2 = 8.6/11 ms) on water, 13O/12N on graphite, 43Ti/41Sc/42Sc (T1/2 = 509 - 680 ms) on calcium, 28P (T1/2 = 268 ms) on phosphorus. A translation of the results from elemental targets to PMMA and representative tissues such as adipose tissue, muscle, compact and cortical bone, shows the dominance of 13O/12N in at least the first 20 s of an irradiation with 4...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
To quantify the effects of the Bragg peak degradation due to lung tissue on treatment plans of lung cancer patients with spot scanning proton therapy and to give a conservative approximation of these effects.
Source: Radiation Oncology - Category: Cancer & Oncology Authors: Tags: Research Source Type: research
There are no established imaging biomarkers that predict response during chemoradiation for patients with locally-advanced NSCLC (LA-NSCLC). At our institution, proton therapy (PT) patients undergo repeat CT-simulations twice during radiation. We hypothesized that tumor regression measured on these scans would separate early and late responders, and that early response would translate into better outcomes.
Source: International Journal of Radiation Oncology * Biology * Physics - Category: Radiology Authors: Source Type: research
Abstract Background: The aim of this study was to compare adaptive intensity modulated proton therapy (IMPT) robustness and organ sparing capabilities with that of adaptive volumetric arc photon therapy (VMAT). Material and methods: Eighteen lung cancer patients underwent a planning 4DCT (p4DCT) and 5 weekly repeated 4DCT (r4DCT) scans. Target volumes and organs at risk were manually delineated on the three-dimensional (3D) average scans of the p4DCT (av_p4DCT) and of the r4DCT scans (av_r4DCT). Planning target volume (PTV)-based VMAT plans and internal clinical target volume (ICTV)-based robust IMPT plans were op...
Source: Acta Oncologica - Category: Cancer & Oncology Authors: Tags: Acta Oncol Source Type: research
Spot scanning proton therapy provides more conformal target dose distributions compared to the uniform scanning and double-scattering proton beam delivery techniques. [1,2] However, an unwarranted change in spot size and spot position can affect the quality of treatment beam delivery and patient treatment plan [3]. Therefore, the size and position of a pencil proton beam are measured as a part of quality assurance (QA) program [2].
Source: Physica Medica: European Journal of Medical Physics - Category: General Medicine Authors: Tags: Technical note Source Type: research
Abstract Proton beam therapy is a highly conformal form of radiation therapy, which currently represents an important therapeutic component in multidisciplinary management in paediatric oncology. The precise adjustability of protons results in a reduction of radiation-related long-term side-effects and secondary malignancy induction, which is of particular importance for the quality of life. Proton irradiation has been shown to offer significant advantages over conventional photon-based radiotherapy, although the biological effectiveness of both irradiation modalities is comparable. This review evaluates current d...
Source: The British Journal of Radiology - Category: Radiology Authors: Tags: Br J Radiol Source Type: research
Conclusion: The rate of symptomatic brainstem necrosis was extremely low after treatment with PBS-PT in this study. Further work to clarify clinical and dosimetric parameters associated with risk of brainstem necrosis after PBS-PT is needed. PMID: 31512931 [PubMed - as supplied by publisher]
Source: Acta Oncologica - Category: Cancer & Oncology Authors: Tags: Acta Oncol Source Type: research
In this study, the impact of realistic inline MRI fringe field on IMPT plan delivery is investigated for a water phantom, liver tumor and prostate cancer differing in target volume, shape, and field configuration using Monte Carlo simulations. A method to correct for the shift of the beam spot positions in the presence of the inline magnetic field is presented. Results show that when not accounting for the effect of the magnetic field on the pencil beam delivery, the spot positions are substantially shifted and the quality of delivered plans is significantly deteriorated leading to dose inhomogeneities and creation of hot ...
Source: Physics in Medicine and Biology - Category: Physics Authors: Tags: Phys Med Biol Source Type: research
ConclusionsProton beam radiotherapy for prostate cancer is feasible with a low rate of acute toxicity and promising late toxicity and effectivity.
Source: Journal of Medical Imaging and Radiation Oncology - Category: Radiology Authors: Tags: Radiation Oncology —Original Article Source Type: research
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