Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy

Xie, Y.; Bentefour, El Hassane; Janssens, Guillaume; Smeets, J.; Stappen, F. Vander; Hotoiu, L.; Yin, Lingshu; Dolney, Derek; Avery, Stephen; O’grady, F.; Prieels, D.; McDonough, James E.; Solberg, Timothy D.; Lustig, Robert A.; Lin, Alexander; Teo, Boon K.

doi:10.1016/j.ijrobp.2017.04.027

Cited by 145 publications

(170 citation statements)

References 18 publications

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“…Their horizontal error bar is set to 0.5 mm (commissioning tolerance), while the vertical error represents the predicted statistical uncertainty ∆ s ×Ṅ d,all assuming N p = 10 8 protons per spot cluster. 20 30 40 Modeled γ-ray count rateṄ d,all as a function of proton range Rw, cf. eqs.…”

Section: Resultsmentioning

confidence: 99%

“…It is common practice in Pencil Beam Scanning (PBS) to aggregate data from neighboring spots [20], [21], [42] in order to achieve around N p ∼ 10 8 protons per cluster. Since the lateral spread of the pencil beam close to the proton range is often larger than the lateral separation between pencil beams, an improvement in statistical precision can be achieved without significant loss in lateral resolution.…”

Section: Detectionmentioning

confidence: 99%

“…The second technique, proposed in 2003 [17], has shown promising advances in recent years [18]. First clinical tests were done with a knife-edge slit PGI camera [19], [20], and a clinical study with a Prompt Gamma-ray Spectroscopy (PGS) camera [21] is foreseen. Both camera prototypes rely on a passive collimation of prompt γ-rays (with energies up to ∼6 MeV) and are able to detect the proton range in clinical conditions with a few millimeters precision.…”

Section: Introductionmentioning

confidence: 99%

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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.

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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.

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Section: Resultsmentioning

confidence: 99%

Section: Detectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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.

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“…There are currently two PGI systems based on collimated systems that have reached the clinical prototype for proton range verification. The first application in men was the knife‐edge slit camera from IBA * 18,19 . This device retrieves the relative changes in the total prompt gamma emission profile along the Bragg peak.…”

Section: Introductionmentioning

confidence: 99%

“…The first application in men was the knifeedge slit camera from IBA*. 18,19 This device retrieves the relative changes in the total prompt gamma emission profile along the Bragg peak. The second prototype is a promptgamma spectroscope developed at the MGH † that measures the absolute deviations with respect to the plan and it is foreseen for application in a upcoming clinical study.…”

Section: Introductionmentioning

confidence: 99%

Results from the experimental evaluation of CeBr scintillators for He prompt gamma spectroscopy

et al. 2019

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Purpose The presence of range uncertainties hinders the exploitation of the full potential of charged particle therapy. Several range verification techniques have been proposed to mitigate this limitation. Prompt gamma spectroscopy (PGS) is among the most promising solutions for online and in vivo range verification. In this work, we present the experimental results of the detection of prompt gamma radiation, induced by 4He beams at the Heidelberg Ion‐Beam Therapy Center (HIT). The results were obtained, using a spectroscopic unit of which the design has been optimized using Monte Carlo simulations. Methods The spectroscopic unit is composed by a primary cerium bromide (CeBr3) crystal surrounded by a secondary bismuth germanate (BGO) crystal for anticoincidence detection (AC). The digitalization of the signals is performed with an advanced FADC/FPGA system. The 4He beams at clinical energies and intensities are delivered to multiple targets in the experimental cave at the HIT. We analyze the production of prompt gamma on oxygen and carbon targets, as well as high Z materials such as titanium and aluminum. The quantitative analysis includes a systematic comparison of the signal‐to‐noise ratio (SNR) improvement for the spectral lines when introducing the AC detection. Moreover, the SNR improvement could provide a reduction of the number of events required to draw robust conclusions. We perform a statistic analysis to determine the magnitude of such an effect. Results We present the energy spectra detected by the primary CeBr3 and the secondary BGO. The combination of these two detectors leads to an average increase of the signal‐to‐noise ratio by a factor 2.1, which confirms the Monte Carlo predictions. The spectroscopic unit is capable of detecting efficiently the discrete gamma emission over the full energy spectrum. We identify and analyze 19 independent spectral lines in an energy range spacing from Eγ=0.718 MeV to Eγ=6.13 MeV. Moreover, when introducing the AC detection, the number of events required to determine robustly the intensity of the discrete lines decreases. Finally, the analysis of the low‐energy reaction lines determines whether a thin metal insert is introduced in the beam direction. Conclusions This work provides the experimental characterization of the spectroscopy unit in development for range verification through PGS at the HIT. Excellent performances have been demonstrated over the full prompt gamma energy spectrum with 4He beams at clinical energies and intensities.

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Technology‐driven research for radiotherapy innovation

et al. 2020

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Technology has a pivotal role in the continuous development of radiotherapy. The long road toward modern ‘high‐tech’ radiation oncology has been studded with discoveries and technological innovations that resulted from the interaction of various disciplines. In the last decades, a dramatic technology‐driven revolution has hugely improved the capability of accurately and safely delivering complex‐shaped dose distributions. This has contributed to many clinical improvements, such as the successful management of lung cancer and oligometastatic disease through stereotactic body radiotherapy. Technology‐driven research is an active and lively field with promising potential in several domains, including image guidance, adaptive radiotherapy, integration of artificial intelligence, heavy‐particle therapy, and ‘flash’ ultra‐high dose‐rate radiotherapy. The evolution toward personalized Oncology will deeply influence technology‐driven research, aiming to integrate predictive models and omics analyses into fast and efficient solutions to deliver the best treatment for each single patient. Personalized radiation oncology will need affordable technological solutions for middle‐/low‐income countries, as these are expected to experience the highest increase of cancer incidence and mortality. Moreover, technology solutions for automation of commissioning, quality assurance, safety tests, image segmentation, and plan optimization will be required. Although a large fraction of cancer patients receive radiotherapy, this is certainly not reflected in the worldwide budget for radiotherapy research. Differently from the pharmaceutical companies‐driven research, resources for research in radiotherapy are highly limited to equipment vendors, who can, in turn, initiate a limited number of collaborations with academic research centers. Thus, enhancement of investments in technology‐driven radiotherapy research via public funds, national governments, and the European Union would have a crucial societal impact. It would allow for radiotherapy to further strengthen its role as a highly effective and cost‐efficient cancer treatment modality, and it could facilitate a rapid and equalitarian large‐scale transfer of technology to clinic, with direct impact on patient care.

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Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy

Cited by 145 publications

References 18 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

Results from the experimental evaluation of CeBr scintillators for He prompt gamma spectroscopy

Technology‐driven research for radiotherapy innovation

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