Multivariate statistical modelling to improve particle treatment verification: Implications for prompt gamma-ray timing

Schellhammer, Sebastian; Wiedkamp, Julia; Löck, Steffen; Kögler, T.

doi:10.3389/fphy.2022.932950

Cited by 8 publications

(10 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It converged at three to four parameters per model, without further relevant improvement when adding more parameters. This result is consistent with previous results for the prompt gamma-ray timing system [10]. Next to the area under the curve, the median and the mean absolute deviation of the distributions were chosen as predictive features.…”

Section: Predictive Distribution Parameterssupporting

confidence: 89%

See 1 more Smart Citation

Hybrid treatment verification based on prompt gamma rays and fast neutrons: multivariate modelling for proton range determination

Schellhammer,

Meric,

Löck

et al. 2023

Front. Phys.

View full text Add to dashboard Cite

Robust and fast in vivo treatment verification is expected to increase the clinical efficacy of proton therapy. The combined detection of prompt gamma rays and neutrons has recently been proposed for this purpose and shown to increase the monitoring accuracy. However, the potential of this technique is not fully exploited yet since the proton range reconstruction relies only on a simple landmark of the particle production distributions. Here, we apply machine learning based feature selection and multivariate modelling to improve the range reconstruction accuracy of the system in an exemplary lung cancer case in silico. We show that the mean reconstruction error of this technique is reduced by 30%–50% to a root mean squared error per spot of 0.4, 1.0, and 1.9 mm for pencil beam scanning spot intensities of 108, 107, and 106 initial protons, respectively. The best model performance is reached when combining distribution features of both gamma rays and neutrons. This confirms the advantage of hybrid gamma/neutron imaging over a single-particle approach in the presented setup and increases the potential of this system to be applied clinically for proton therapy treatment verification.

show abstract

Section: Predictive Distribution Parameterssupporting

confidence: 89%

“…The method is described in detail in [10]. First, relevant distribution features were calculated from both the fast neutron and the prompt gamma-ray distributions based on the Image Biomarker Standardisation Initiative parameter set [11].…”

Section: Range Reconstruction By Multivariate Modellingmentioning

confidence: 99%

Hybrid treatment verification based on prompt gamma rays and fast neutrons: multivariate modelling for proton range determination

Schellhammer,

Meric,

Löck

et al. 2023

Front. Phys.

View full text Add to dashboard Cite

show abstract

“…Another important aspect is the method by which RLs are calculated is likely to have an effect on the final range-monitoring accuracy. Therefore, a multivariate statistical modelling study has also been initiated to determine the RL calculation method or combinations of methods whereby the accuracy can be improved 24 .…”

Section: Discussionmentioning

confidence: 99%

A hybrid multi-particle approach to range assessment-based treatment verification in particle therapy

Meriç

Alagoz

Hysing

et al. 2023

Sci Rep

Self Cite

View full text Add to dashboard Cite

Particle therapy (PT) used for cancer treatment can spare healthy tissue and reduce treatment toxicity. However, full exploitation of the dosimetric advantages of PT is not yet possible due to range uncertainties, warranting development of range-monitoring techniques. This study proposes a novel range-monitoring technique introducing the yet unexplored concept of simultaneous detection and imaging of fast neutrons and prompt-gamma rays produced in beam-tissue interactions. A quasi-monolithic organic detector array is proposed, and its feasibility for detecting range shifts in the context of proton therapy is explored through Monte Carlo simulations of realistic patient models and detector resolution effects. The results indicate that range shifts of $${1}\,\hbox {mm}$$ 1 mm can be detected at relatively low proton intensities ($$22.30(13)\times 10^{7}$$ 22.30 ( 13 ) × 10 7 protons/spot) when spatial information obtained through imaging of both particle species are used simultaneously. This study lays the foundation for multi-particle detection and imaging systems in the context of range verification in PT.

show abstract

“…With a time resolution of 100 ps and the specified maximum throughput, the PETsys setup appears to meet the high requirements for a next generation range verification system. However, in order to achieve the required range resolution of approximately 1 mm, detection of at least 2000 photons per detector channel is required [11,55]. A full gamma detection system could then be composed of finely segmented scintillator crystal arrays of sufficient energy coverage, read out by geometrically adapted SiPM matrices and PETsys ASICs.…”

Section: Discussionmentioning

confidence: 99%

Characterisation of a high granularity multi-channel prompt γ-ray detection system prototype for proton range verification based on the PETsys TOFPET2 ASIC

Novgorodova,

Glatte,

Hentges

et al. 2024

J. Inst.

View full text Add to dashboard Cite

Proton therapy requires range verification in order to exploit its full potential. One of the most promising approaches is to monitor prompt gamma-rays produced by nuclear interactions of the therapeutic particles in the patient tissues. A detector with a wide energy range from 100 keV to 15 MeV and excellent time resolution is required to achieve millimetric precision in proton range. During patient treatment, the detector count rates are usually above 106 s-1 and the fraction of pile-up events is very high for commonly used fast inorganic scintillators. We are investigating a full acceptance approach with increased granularity in order to reduce the size of the scintillators and consequently the count rate per channel. Stacking the scintillators in matrices requires suitable multi-channel photo-multipliers and a fitting acquisition system. Here, we present two geometries of CeBr3 crystals 5×5×20 mm3 and 10×10×30 mm3, together with modern silicon photo-multipliers (SiPM) adapted to work with the PETsys TOFPET2 ASIC. The TOFPET2 ASIC was developed for Time-of-Flight Positron Emission Tomography (TOF-PET) applications. Here we show its potential for higher gamma-ray energies and future hybrid imaging. First results of energy resolution of 6.1%–7.8% are achieved at 3.42 MeV using a 241Am9Be source. The time resolution was found to be below 100 ps and studies of the count rates and the dead time of the full system were performed. Different SiPM models are analysed for their impact on the coincidence time resolution.

show abstract

Multivariate statistical modelling to improve particle treatment verification: Implications for prompt gamma-ray timing

Cited by 8 publications

References 14 publications

Hybrid treatment verification based on prompt gamma rays and fast neutrons: multivariate modelling for proton range determination

Hybrid treatment verification based on prompt gamma rays and fast neutrons: multivariate modelling for proton range determination

A hybrid multi-particle approach to range assessment-based treatment verification in particle therapy

Characterisation of a high granularity multi-channel prompt γ-ray detection system prototype for proton range verification based on the PETsys TOFPET2 ASIC

Contact Info

Product

Resources

About