Detection systems for range monitoring in proton therapy: Needs and challenges

Pausch, G.; Berthold, Jonathan; Enghardt, W.; Römer, K.; Straessner, A.; Wagner, A.; Werner, T.; Kögler, T.

doi:10.1016/j.nima.2018.09.062

Cited by 49 publications

(47 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the majority of proton ranges R w and cavity positions z κ , the expected count change is higher than the statistical measurement uncertainty for N p = 10 8 delivered protons. 30 40 50 Relative count variation ∆κ / % Fig. 6.…”

Section: Resultsmentioning

confidence: 99%

“…The beam current in a proton therapy facility is a critical factor challenging the electronics and affecting the feasibility of PGI devices [30], [31]. For the widespread Cyclone R 230 (C230) isochronous cyclotron of IBA (Louvain-la-Neuve, Belgium), the instantaneous proton beam current I p is approximately constant at 2 nA [47] at the beam exit window.…”

Section: F Detector Count Ratementioning

confidence: 99%

“…Range verification devices based on PGI are usually designed for a specific type of proton accelerator used at the developing institution. Consequently, the results cannot be directly translated to other types of accelerators, since the expected beam current and beam time structure [30], [53], [82] might be drastically different. In the case of CPGM, we focus on the most widespread accelerator type [83], and the conclusions drawn in this study might potentially not be extrapolated to facilities with a different machine type.…”

Section: Compatibility and Applicabilitymentioning

confidence: 99%

“…This article is framed in this context: The need for providing a range verification system in every treatment room of every proton therapy facility at an affordable cost. To that extent, the experience from the current clinical prototypes is essential, but innovative approaches have to be developed to reduce their weight, price and complexity, while still addressing the required precision and associated technical challenges [30].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: A Theoretical Study

Hueso-González

Bortfeld

2020

IEEE Trans. Radiat. Plasma Med. Sci.

View full text Add to dashboard Cite

Range uncertainties in proton therapy hamper treatment precision. Prompt gamma-rays were suggested 16 years ago for real-time range verification, and have already shown promising results in clinical studies with collimated cameras. Simultaneously, alternative imaging concepts without collimation are investigated to reduce the footprint and price of current prototypes. In this manuscript, a compact range verification method is presented. It monitors prompt gamma-rays with a single scintillation detector positioned coaxially to the beam and behind the patient. Thanks to the solid angle effect, proton range deviations can be derived from changes in the number of gammarays detected per proton, provided that the number of incident protons is well known. A theoretical background is formulated and the requirements for a future proof-of-principle experiment are identified. The potential benefits and disadvantages of the method are discussed, and the prospects and potential obstacles for its use during patient treatments are assessed. The final milestone is to monitor proton range differences in clinical cases with a statistical precision of 1 mm, a material cost of 25000 USD and a weight below 10 kg. This technique could facilitate the widespread application of in vivo range verification in proton therapy and eventually the improvement of treatment quality.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: F Detector Count Ratementioning

confidence: 99%

Section: Compatibility and Applicabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: A Theoretical Study

Hueso-González

Bortfeld

2020

IEEE Trans. Radiat. Plasma Med. Sci.

View full text Add to dashboard Cite

show abstract

“…It is clear from Figure 10 that increasing the number of helium ions per pulse results, as expected, in a better precision of the range shift measurement. The precision of the range measurement should be ideally better than 2 mm in order for it to be clinically relevant [86,87]. For the delivery of a dose of 1 Gy during irradiations with protons, the most intense distal layer spot contains about 2 × 10 8 protons [43].…”

Section: Discussionmentioning

confidence: 99%

Real-Time PET Imaging for Range Verification of Helium Radiotherapy

et al. 2020

View full text Add to dashboard Cite

Real-time range verification of particle beams is important for optimal exploitation of the tissue-sparing advantages of particle therapy. Positron Emission Tomography (PET) of the beam-induced positron emitters such as 15 O (T 1/2 = 122 s) and 11 C (T 1/2 = 1223 s) has been used for monitoring of therapy in both clinical and preclinical studies. However, the half-lives of these nuclides preclude prompt feedback, i.e., on a sub-second timescale, on dose delivery. The in vivo verification technique relying on the in-beam PET imaging of very short-lived positron emitters such as 12 N (T 1/2 = 11 ms), recently proposed and investigated in feasibility experiments with a proton beam, provides millimeter precision in range measurement a few tens of milliseconds after the start of an irradiation. With the increasing interest in helium therapy, it becomes relevant to study the feasibility of prompt feedback using PET also for helium beams. A recent study has demonstrated the production of very short-lived nuclides (T 1/2 = 10 ms attributed to 12 N and/or 13 O) during irradiation of water and graphite with helium ions. This work is aimed at investigating the range verification potential of imaging these very short-lived nuclides. PMMA targets were irradiated with a 90 AMeV 4 He pencil beam consisting of a series of pulses of 10 ms beam-on and 90 ms beam-off. Two modules of a modified Siemens Biograph mCT PET scanner (21 × 21 cm 2), installed 25 cm apart, were used to image the beam-induced PET activity during the beam-off periods. For the irradiation of PMMA, we identify the very short-lived activity earlier observed to be 12 N (T 1/2 = 11.0 ms). The range precision determined from the 12 N activity profile that is measured after just one beam pulse was found to be 9.0 and 4.1 mm (1σ) with 1.3 × 10 7 4 He ions per pulse and 6.6 × 10 7 4 He ions per pulse, respectively. When considering 4.0 × 10 7 4 He ions, which is about the intensity of the most intense distal layer spot in a helium therapy plan, a range verification precision in PMMA of 5.7 mm (1σ) can be realized. The range precision scales approximately with the inverse square root of the number of 4 He ions, i.e., the relative statistical accuracy of the number of coincidence events. Thus, when summing data over about 10 distal layer spots, this study shows good prospects for obtaining 1.8 mm (1σ) precision in range verification, within 50 ms after the start of a helium irradiation by in-beam PET imaging (scanner 29% solid angle) of 12 N.

show abstract

Analytic prediction of droplet vaporization events to estimate the precision of ultrasound‐based proton range verification

Collado-Lara

Heymans

Rovituso³

et al. 2023

Medical Physics

View full text Add to dashboard Cite

Background:The safety and efficacy of proton therapy is currently hampered by range uncertainties. The combination of ultrasound imaging with injectable radiation-sensitive superheated nanodroplets was recently proposed for in vivo range verification. The proton range can be estimated from the distribution of nanodroplet vaporization events, which is stochastically related to the stopping distribution of protons, as nanodroplets are vaporized by protons reaching their maximal LET at the end of their range. Purpose: Here, we aim to estimate the range estimation precision of this technique. As for any stochastic measurement, the precision will increase with the sample size, that is, the number of detected vaporizations. Thus, we first develop and validate a model to predict the number of vaporizations, which is then applied to estimate the range verification precision for a set of conditions (droplet size, droplet concentration, and proton beam parameters). Methods: Starting from the thermal spike theory, we derived a model that predicts the expected number of droplet vaporizations in an irradiated sample as a function of the droplet size, concentration, and number of protons. The model was validated by irradiating phantoms consisting of size-sorted perfluorobutane droplets dispersed in an aqueous matrix. The number of protons was counted with an ionization chamber, and the droplet vaporizations were recorded and counted individually using high frame rate ultrasound imaging. After validation, the range estimate precision was determined for different conditions using a Monte Carlo algorithm. Results: A good agreement between theory and experiments was observed for the number of vaporizations, especially for large (5.8 ± 2.2 µm) and medium (3.5 ± 1.1 µm) sized droplets. The number of events was lower than expected in phantoms with small droplets (2.0 ± 0.7 µm), but still within the same order of magnitude. The inter-phantom variability was considerably larger (up to 30x) than predicted by the model. The validated model was then combined with Monte Carlo simulations, which predicted a theoretical range retrieval precision improving with the square-root of the number of vaporizations, and degrading at high beam energies due to range straggling. For single pencil beams withThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

show abstract

Detection systems for range monitoring in proton therapy: Needs and challenges

Cited by 49 publications

References 42 publications

Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: A Theoretical Study

Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: A Theoretical Study

Real-Time PET Imaging for Range Verification of Helium Radiotherapy

Analytic prediction of droplet vaporization events to estimate the precision of ultrasound‐based proton range verification

Contact Info

Product

Resources

About