Towards clinical application: prompt gamma imaging of passively scattered proton fields with a knife-edge slit camera

Priegnitz, Marlen; Barczyk, Steffen; Nenoff, Lena; Golnik, C.; Keitz, I.; Werner, T.; Mein, Stewart; Smeets, J.; Stappen, F. Vander; Janssens, Guillaume; Hotoiu, L.; Fiedler, F.; Prieels, D.; Enghardt, W.; Pausch, G.; Richter, Christian

doi:10.1088/0031-9155/61/22/7881

Cited by 26 publications

(20 citation statements)

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“…This study assumes that the treatment cases are monitored with an IBA slit camera. 16,25,29 This camera consists of two rows of 20 individual scintillation detectors and a knife-edge slit of tungsten alloy collimator. It detects energy depositions of gamma rays between 3 and 6 MeV.…”

Section: B1 Ground-truth Prompt-gamma Datasetmentioning

confidence: 99%

“…23,24 Previous studies have demonstrated the accuracy and sensitivity of the PGI slit camera in both homogeneous and heterogeneous phantoms. [25][26][27] Furthermore, proof-of-principle clinical applications of the slit camera have been performed in both, double scattering and pencil-beam scanning (PBS) treatments. 23,24 However, pure detection of spot-wise range shift might be difficult to interpret concerning clinical relevance and potential source of deviation.…”

Section: Introductionmentioning

confidence: 99%

“…Detection of deviations beyond a threshold by means of machine learning analysis of PGI information was introduced by Gueth et al 28 and demonstrated for one spot of a prostate treatment plan, with restriction to patient translation errors. The purpose of the present simulation study was to investigate the feasibility of a PGI-based automated classification of several types of the error sources for head and neck tumor treatments when using the PGI slit camera system from Ion Beam Applications (IBA, Louvain-la-Neuve, Belgium), 16,25,29 shifting focus from spot-wise detection of deviations to global analysis of patterns of deviations from all spots. A decision tree model was heuristically established and developed with known error scenarios in phantom and patient scenarios of different geometrical complexity.…”

Section: Introductionmentioning

confidence: 99%

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Classification of the source of treatment deviation in proton therapy using prompt‐gamma imaging information

et al. 2020

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Conclusions: In this simulation study it was demonstrated that the source of a treatment deviation can be identified from simulated noiseless PGI information in head and neck tumor treatments with high sensitivity and specificity. The application, refinement, and evaluation of the approach on measured PGI data will be the next step to show the clinical feasibility of PGI-based error source classification.

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Section: B1 Ground-truth Prompt-gamma Datasetmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Classification of the source of treatment deviation in proton therapy using prompt‐gamma imaging information

et al. 2020

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“…The other coordinates can be obtained on a spot-by-spot basis for pencil beam scanning via a synchronization with the beam delivery system. Clinical tests have been performed using the knife-edge slit camera at the OncoRay facility for passively double scattered proton beams (Priegnitz et al, 2016). Shifts in the proton range of 2 to 5 mm could be detected using this technique.…”

Section: Knife-edge Slit Cameramentioning

confidence: 99%

“…Prompt gamma ray imaging using a knife-edge slit camera has been used in a clinical setting for a double scattering proton therapy irradiation Priegnitz et al (2016); Richter et al (2016). The sensitivity of the imaging device for several beam delivery techniques was investigated by Nenoff et al (2017), showing that applied range shifts were measured with 1 to 3 mm accuracy for IMPT and single field uniform dose (SFUD) beam delivery.…”

Section: Overview Of the Current State Of Pet And Prompt Gamma Detectmentioning

confidence: 99%

Positron emission tomography for quality assurance in proton therapy

Buitenhuis¹

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Introduction Cancer is one of the leading causes of death in The Netherlands. In 2017, all types of cancer combined caused 47,000 of 150,000 recorded causes of death (Centraal Bureau voor de Statistiek, 2017). There are several ways to treat cancer. The most common treatments include radiotherapy, surgery, chemotherapy, targeted therapy, hormonal therapy and immunotherapy. Often, different treatment modalities are combined to maximize their efficacy. For example, patients might receive radiotherapy after surgery to remove any traces of cancer cells that were left. Radiotherapy uses ionizing radiation to kill tumor cells by damaging their DNA. This radiation can be applied internally (brachytherapy) or externally. For brachytherapy, radioactive sources are implanted in and around the tumor, which deliver dose directly at the right location. However, for this method, the tumor needs to be in a relatively easily accessible location. For some patients, radioactive substances that accumulate in the tumor are injected. This radiation then delivers most dose at the site where it accumulates. More often, the radiation is applied using a source outside of the body. In the past, radioactive sources such as 60 Co were used to supply MeV gamma rays. Nowadays, a linear accelerator is used in most radiotherapy facilities to produce MeV electron beams. These electrons are stopped in a tungsten absorber to generate MeV X-rays, which penetrate deeply into the body. Other particles can also be used, such as protons or even heavier nuclides. Accelerating these particles to clinically useful energies requires large particle accelerators. Already in 1946, Robert R. Wilson wrote about how protons with an energy in the order of 100 MeV are very interesting for radio-3. Beam-on imaging of short-lived positron emitters during proton therapy proton bunches, such as prompt gamma rays, were removed from the data via an anti-coincidence filter with the cyclotron RF. The resulting energy spectrum allowed good identification of the 511 keV PET counts during beam-on. A method was developed to subtract the long-lived background from the 12 N image by introducing a beam-off period into the cyclotron beam time structure. We measured 2D images and 1D profiles of the 12 N distribution. A range shift of 5 mm was measured as 6 ± 3 mm using the 12 N profile. A larger, more efficient, PET system with a higher data throughput capability will allow beam-on 12 N PET imaging of single spots in the distal layer of an irradiation with an increased signal-to-background ratio and thus better accuracy. A simulation shows that a large dual panel scanner, which images a single spot directly after it is delivered, can measure a 5 mm range shift with millimeter accuracy: 5.5 ± 1.1 mm for 1.64 × 10 8 protons and 5.2 ± 0.5 mm for 8.2 × 10 8 protons. This makes fast and accurate feedback on the dose delivery during treatment possible.

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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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Towards clinical application: prompt gamma imaging of passively scattered proton fields with a knife-edge slit camera

Cited by 26 publications

References 32 publications

Classification of the source of treatment deviation in proton therapy using prompt‐gamma imaging information

Classification of the source of treatment deviation in proton therapy using prompt‐gamma imaging information

Positron emission tomography for quality assurance in proton therapy

In vivo range verification in particle therapy

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