Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

Solevi, P.; Muñoz, Enrique; Solaz, C.; Trovato, M.; Dendooven, P.; Gillam, J. E.; Lacasta, C.; Oliver, J.; Rafecas, M.; Torres-Espallardó, I.; Llosá, G.

doi:10.1088/0031-9155/61/14/5149

Cited by 48 publications

(38 citation statements)

References 32 publications

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“…In fact, each element in tissue emits a unique spectrum of PGs during proton irradiation 135–137 . In addition to the already reported use of the best emission lines for range verification 74,76, 87, 89, 111,113 , it has also been shown that the total emission from oxygen per unit dose is directly proportional to the concentration of oxygen within a proton beam irradiated volume of tissue 138 . This observation led to suggestions that if PG emissions from several key elements in tissue (O, C, N, Ca, etc.)…”

Section: Discussionmentioning

confidence: 90%

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In vivo range verification in particle therapy

2018

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Exploitation of the full potential offered by ion beams in clinical practice is still hampered by several sources of treatment uncertainties, particularly related to limitations of our ability to locate the position of the Bragg peak in the tumour. To this end, several efforts are ongoing to improve the characterization of patient position, anatomy and tissue stopping power properties prior to treatment, as well as to enable in-vivo verification of the actual dose delivery, or at least beam range, during or shortly after treatment. This contribution critically reviews methods under development or clinical testing for verification of ion therapy, based on pre-treatment range and tissue probing as well as detection of secondary emissions or physiological changes during and after treatment, trying to disentangle approaches of general applicability from those more specific to certain anatomical locations. Moreover, it discusses future directions, which could benefit from integration of multiple modalities or address novel exploitation of the measurable signals for biologically adapted therapy.

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Section: Discussionmentioning

confidence: 90%

“…Several prototype CCs have been constructed and tested in clinical proton therapy environments 110–113 . As shown in Figure 8, one such design currently being tested consists of a two-stage CC mounted on the underside of the treatment couch.…”

Section: General Purpose Techniquesmentioning

confidence: 99%

In vivo range verification in particle therapy

2018

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“…Since the Compton camera (CC) was first proposed for medical imaging (Todd et al , 1974), many researchers have studied its use for a wide range of medical applications, including 2D and 3D imaging of prompt gamma (PG) emission from a patient during proton radiotherapy as a means of providing in vivo verification of the delivered proton beam range (Frandes et al , 2010; Gillam et al , 2011; Golnik et al , 2016; Hueso-Gonzalez et al , 2016; Kim et al , 2013; Kormoll et al , 2011; Krimmer et al , 2015; Llosa et al , 2012; Lojacono et al , 2013; McCleskey et al , 2015; Munoz et al , 2017; Peterson et al , 2010; Polf et al , 2015; Richard et al , 2011; Robertson et al , 2011; Roellinghoff et al , 2014; Rohling et al , 2017; Seo et al , 2010; Solevi et al , 2016; Thirolf et al , 2016; Thirolf et al , 2014). In standard Compton imaging, information pertaining to the energy deposited by and spatial coordinates of gammas that interact at least twice in the stages of a CC is used to create the images.…”

Section: Introductionmentioning

confidence: 99%

“…In addition pair production events, and gammas that Compton scatter twice, but do not deposit their total energy (Hueso-Gonzalez et al , 2017; Ortega et al , 2015; Rohling et al , 2017) also effect the imaging capabilities of the CC. These events greatly increase image noise and reduce the achievable spatial resolution of PG imaging (Ortega et al , 2015; Solevi et al , 2016). One technique researchers have studied to remove and reduce the effects of these “bad scatter events” is by limiting the initial PG energy range to > 2 MeV (Polf et al , 2009b; Rohling et al , 2017) or to an energy window around a specific PG emission lines (Hilaire et al , 2016; Hueso-Gonzalez et al , 2017).…”

Section: Introductionmentioning

confidence: 99%

3D prompt gamma imaging for proton beam range verification

Draeger¹,

Mackin²,

Peterson³

et al. 2018

Phys. Med. Biol.

121

100

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We tested the ability of a single Compton camera (CC) to produce 3-dimensional (3D) images of prompt gammas (PGs) emitted during the irradiation of a tissue-equivalent plastic phantom with proton pencil beams for clinical doses delivered at clinical dose rates. PG measurements were made with a small prototype CC placed at three different locations along the proton beam path. We evaluated the ability of the CC to produce images at each location for two clinical scenarios: (1) the delivery of a single 2 Gy pencil beam from a hypo-fractionated treatment (~9 × 10 protons), and (2) a single pencil beam from a standard treatment (~1 × 10 protons). Additionally, the data measured at each location were combined to simulate measurements with a larger scale, clinical CC and its ability to image shifts in the Bragg peak (BP) range for both clinical scenarios. With our prototype CC, the location of the distal end of the BP could be seen with the CC placed up to 4 cm proximal or distal to the BP distal falloff. Using the data from the simulated full scale clinical CC, 3D images of the PG emission were produced with the delivery of as few as 1 × 10 protons, and shifts in the proton beam range as small as 2 mm could be detected for delivery of a 2 Gy spot. From these results we conclude that 3D PG imaging for proton range verification under clinical beam delivery conditions is possible with a single CC.

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“…It also adds uncertainty because of the need to correlate the proton transit time with a spatial location in the patient. Finally, the application of Compton cameras is being investigated (Hueso-González et al 2017; Solevi et al 2016; Aldawood et al 2017; Rohling et al 2017; Draeger et al 2018). These systems do not require physical collimation either, but rely on the detection of multiple Compton scatter interactions per incident gamma-ray in order to reconstruct its origin region.…”

Section: Introductionmentioning

confidence: 99%

A full-scale clinical prototype for proton range verification using prompt gamma-ray spectroscopy

et al. 2018

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We present a full-scale clinical prototype system for in vivo range verification of proton pencil-beams using the prompt gamma-ray spectroscopy method. The detection system consists of eight LaBr scintillators and a tungsten collimator, mounted on a rotating frame. Custom electronics and calibration algorithms have been developed for the measurement of energy- and time-resolved gamma-ray spectra during proton irradiation at a clinical dose rate. Using experimentally determined nuclear reaction cross sections and a GPU-accelerated Monte Carlo simulation, a detailed model of the expected gamma-ray emissions is created for each individual pencil-beam. The absolute range of the proton pencil-beams is determined by minimizing the discrepancy between the measurement and this model, leaving the absolute range of the beam and the elemental concentrations of the irradiated matter as free parameters. The system was characterized in a clinical-like situation by irradiating different phantoms with a scanning pencil-beam. A dose of 0.9 Gy was delivered to a [Formula: see text] cm target with a beam current of 2 nA incident on the phantom. Different range shifters and materials were used to test the robustness of the verification method and to calculate the accuracy of the detected range. The absolute proton range was determined for each spot of the distal energy layer with a mean statistical precision of 1.1 mm at a 95% confidence level and a mean systematic deviation of 0.5 mm, when aggregating pencil-beam spots within a cylindrical region of 10 mm radius and 10 mm depth. Small range errors that we introduced were successfully detected and even large differences in the elemental composition do not affect the range verification accuracy. These results show that our system is suitable for range verification during patient treatments in our upcoming clinical study.

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Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams

Cited by 48 publications

References 32 publications

In vivo range verification in particle therapy

In vivo range verification in particle therapy

3D prompt gamma imaging for proton beam range verification

A full-scale clinical prototype for proton range verification using prompt gamma-ray spectroscopy

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