Intensity modulated proton therapy and its sensitivity to treatment uncertainties 1: the potential effects of calculational uncertainties

Lomax, Anthony

doi:10.1088/0031-9155/53/4/014

Cited by 326 publications

(362 citation statements)

References 40 publications

Supporting

Mentioning

355

Contrasting

Order By: Relevance

“…In general, protons are more sensitive to density heterogeneities (like air gaps, air-tissue-bone transitions) than photons [33][34][35]. Hence, image guidance and patient positioning are even more important.…”

Section: Discussionmentioning

confidence: 99%

The Potential Benefit of Radiotherapy with Protons in Head and Neck Cancer with Respect to Normal Tissue Sparing: A Systematic Review of Literature

et al. 2011

View full text Add to dashboard Cite

Purpose. Clinical studies concerning head and neck cancer patients treated with protons reporting on radiation-induced side effects are scarce. Therefore, we reviewed the literature regarding the potential benefits of protons compared with the currently used photons in terms of lower doses to normal tissue and the potential for fewer subsequent radiation-induced side effects, with the main focus on in silico planning comparative (ISPC) studies.Materials and Methods. A literature search was performed by two independent researchers on ISPC studies that included proton-based and photon-based irradiation techniques.Results. Initially, 877 papers were retrieved and 14 relevant and eligible ISPC studies were identified and included in this review. Four studies included paranasal sinus cancer cases, three included nasopharyngeal cancer cases, and seven included oropharyngeal, hypopharyngeal, and/or laryngeal cancer cases. Seven studies compared the most sophisticated photon and proton techniques: intensity-modulated photon therapy versus intensity-modulated proton therapy (IMPT). Four studies compared different proton techniques. All studies showed that protons had a lower normal tissue dose, while keeping similar or better target coverage. Two studies found that these lower doses theoretically translated into a significantly lower incidence of salivary dysfunction.Conclusion. The results of ISPC studies indicate that protons have the potential for a significantly lower normal tissue dose, while keeping similar or better target coverage. Scanned IMPT probably offers the most advantage and will allow for a substantially lower probability of radiation-induced side effects. The results of these ISPC studies should be confirmed in properly designed clinical trials. The Oncologist 2011;16:366 -377

show abstract

Section: Discussionmentioning

confidence: 99%

The Potential Benefit of Radiotherapy with Protons in Head and Neck Cancer with Respect to Normal Tissue Sparing: A Systematic Review of Literature

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Nevertheless, besides its proved benefits [7], the so called intensity modulated particle therapy (IMPT), achieved with the active scanning, has also some drawbacks. In particular it is more sensible to patient positioning or moving [8,9], range uncertainties [10,11] and dose calculation [12]. Therefore, to preserve its high precision and ensure the stability and reproducibility of the treatment, pencil beam scanning (PBS) requires very accurate control and monitoring systems.…”

Section: Delivery Systemsmentioning

confidence: 99%

Control Of The Dose Distribution In Charged Particle Therapy

Manganaro¹,

Attili²,

Dalmasso³

et al. 2017

Proceedings of the 26th International Nuclear Physics Conference — PoS(INPC2016)

View full text Add to dashboard Cite

The use of ions in radiation therapy aims at improving the selectivity of the irradiation thanks to a favourable depth-dose profile and, in case of heavy ions, to their enhanced radiobiological effect. The treatment modality employing actively scanned pencil beams provides highly conformal dose distributions but is sensitive to uncertainties in the dose calculation, delivery and measurement. During the treatment, the delivery of the beam has to be controlled in real time and monitored with high accuracy, including any effect due to patient positioning and motion. Based on the experience gained in the collaboration with the CNAO (Centro Nazionale di Adroterapia Oncologica, Pavia, Italy), this paper is intended to give an overview of recent techniques and trends for the delivery, measurement and verification of the dose distribution in charged particle therapy with scanned ion beams, focusing in particular on real time and online techniques.

show abstract

“…Lomax [28] has described how the combined effects of the proton's sharp distal fall-off, finite range and multiple Coulomb scattering can have an impact on the sensitivity of plans to density heterogeneities in the patient. The Paul Scherrer Institute in Switzerland has biologically calibrated its CT scanner to have an accuracy of 1% for soft tissue and 2% for bony tissue, but, owing to inherent errors such as beam hardening, reconstruction artefacts and reconstruction algorithms [28], it has been stated that an error in HU value of 3% is more realistic.…”

Section: Range Calculation In the Treatment Planning Systemmentioning

confidence: 99%

“…The Paul Scherrer Institute in Switzerland has biologically calibrated its CT scanner to have an accuracy of 1% for soft tissue and 2% for bony tissue, but, owing to inherent errors such as beam hardening, reconstruction artefacts and reconstruction algorithms [28], it has been stated that an error in HU value of 3% is more realistic. To investigate the effect of this error, each plan was recalculated with the HU value increased and decreased by 3% to simulate an undershoot and overshoot scenario.…”

Section: Range Calculation In the Treatment Planning Systemmentioning

confidence: 99%

Treatment planning optimisation in proton therapy

McGowan¹,

Burnet²,

Lomax³

2013

BJR

Self Cite

View full text Add to dashboard Cite

ABSTRACT. The goal of radiotherapy is to achieve uniform target coverage while sparing normal tissue. In proton therapy, the same sources of geometric uncertainty are present as in conventional radiotherapy. However, an important and fundamental difference in proton therapy is that protons have a finite range, highly dependent on the electron density of the material they are traversing, resulting in a steep dose gradient at the distal edge of the Bragg peak. Therefore, an accurate knowledge of the sources and magnitudes of the uncertainties affecting the proton range is essential for producing plans which are robust to these uncertainties. This review describes the current knowledge of the geometric uncertainties and discusses their impact on proton dose plans. The need for patient-specific validation is essential and in cases of complex intensity-modulated proton therapy plans the use of a planning target volume (PTV) may fail to ensure coverage of the target. In cases where a PTV cannot be used, other methods of quantifying plan quality have been investigated. A promising option is to incorporate uncertainties directly into the optimisation algorithm. A further development is the inclusion of robustness into a multicriteria optimisation framework, allowing a multi-objective Pareto optimisation function to balance robustness and conformity. The question remains as to whether adaptive therapy can become an integral part of a proton therapy, to allow re-optimisation during the course of a patient's treatment. The challenge of ensuring that plans are robust to range uncertainties in proton therapy remains, although these methods can provide practical solutions. The ability to create and deliver the ideal treatment plan, where the target volume receives 100% of the prescribed dose and normal tissue receives 0%, is the holy grail of radiation therapy [1]. It is, however, impossible to achieve this perfect balance. Instead, multiple trade-offs are required to achieve a clinically acceptable plan, so the problem becomes one of optimisation. There are many factors that can affect how ''optimised'' a patient's treatment can be. This review focuses on the challenges of proton therapy plan optimisation, particularly in regard to range uncertainties, and how to incorporate them into the plan evaluation and verification process.The nature of proton therapy makes the aim of cure without complications potentially more achievable, owing to the highly localised deposition of dose in the characteristic Bragg peak [2]. This relates predominantly to the ability to deliver high doses of radiation close to normal tissue structures, which would be dose limiting in conventional X-ray treatments, and to the finite range of protons, which results in a reduced integral dose to surrounding normal tissues.From a clinical perspective, the exact role of proton therapy has yet to be defined. However, for childhood cancers, proton therapy delivers a lower dose to tissues around the tumour than X-rays, resulting in less growth disturbance and l...

show abstract

Intensity modulated proton therapy and its sensitivity to treatment uncertainties 1: the potential effects of calculational uncertainties

Cited by 326 publications

References 40 publications

The Potential Benefit of Radiotherapy with Protons in Head and Neck Cancer with Respect to Normal Tissue Sparing: A Systematic Review of Literature

The Potential Benefit of Radiotherapy with Protons in Head and Neck Cancer with Respect to Normal Tissue Sparing: A Systematic Review of Literature

Control Of The Dose Distribution In Charged Particle Therapy

Treatment planning optimisation in proton therapy

Contact Info

Product

Resources

About