Results from a Prototype Proton-CT Head Scanner

Johnson, R. P.; Bashkirov, V.; Coutrakon, G.; Giacometti, Valentina; Karbasi, Paniz; Karonis, Nicholas T.; Ordoñez, C.E.; Pankuch, Mark; Sadrozinski, H. F-W.; Schubert, Keith E.; Schulte, R.

doi:10.1016/j.phpro.2017.09.060

Cited by 26 publications

(26 citation statements)

References 11 publications

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“…Prototype pCT scanners have been designed and constructed (Takada et al 25 1988, Coutrakon et al 2013, Pettersen et al 2016, Esposito et al 2018. In recent studies, the RSP accuracy achieved by some of these prototypes has been reported to be better than 1.6% for three inserts (Esposito et al 2018) and 1.39% for seven inserts (Giacometti et al 2017). For the same seven inserts, Volz et al (2018) achieved accuracy better than 1% using helium ions with a 30 pCT prototype.…”

Section: Introductionmentioning

confidence: 99%

Experimental comparison of proton CT and dual energy x-ray CT for relative stopping power estimation in proton therapy

et al. 2019

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Proton computed tomography (pCT) has been proposed as an alternative to X-ray computed tomography (CT) for acquiring relative to water stopping power (RSP) maps used for proton treatment planning dose calculations. In parallel, it has been shown that dual energy X-ray CT (DECT) improves RSP accuracy when compared to conventional single energy X-ray CT. This study aimed at directly comparing the RSP accuracy of both modalities using phantoms scanned at an advanced prototype pCT scanner and a state-of-the-art DECT scanner. Two phantoms containing 13 tissue-mimicking inserts of known RSP were scanned at the pCT phase II prototype and a latest generation dual-source DECT scanner (Siemens SOMATOM Definition FORCE). RSP accuracy was compared by mean absolute percent error (MAPE) over all inserts. A highly realistic Monte Carlo (MC) simulation was used to gain insight on pCT image artifacts which degraded MAPE. MAPE was 0.55% for pCT and 0.67% for DECT. The realistic MC simulation agreed well with pCT measurements (MAPE = 0.69%).

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Section: Introductionmentioning

confidence: 99%

Experimental comparison of proton CT and dual energy x-ray CT for relative stopping power estimation in proton therapy

et al. 2019

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“…The goal of this work was to investigate the effect of such events on the accuracy of pCT with the prototype detector developed by the US pCT collaboration (Bashkirov et al 2016a, Johnson et al 2017 in Monte Carlo simulations. We investigate the performance of the usual 3 σ WEPL filter and assess the potential of using the ∆E-E filtering technique recently proposed to identify nuclear fragmentation events in helium ion CT (HeCT) with the scanner energy/range detector (Volz et al 2018) to identify nuclear interaction events in pCT.…”

Section: Introductionmentioning

confidence: 99%

Improving single-event proton CT by removing nuclear interaction events within the energy/range detector

Volz¹,

Piersimoni²,

Johnson³

et al. 2019

Phys. Med. Biol.

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Improving single-event proton CT by removing nuclear interaction events within the energy/range detector. Permalink https://escholarship.org/uc/item/5rg9r6rw Journal Physics in medicine and biology, 64 (15) Abstract. Data filtering is crucial for accurate relative stopping power (RSP) reconstruction in proton CT (pCT). In this work, we assess different filters and their performance for the US pCT collaboration prototype pCT system in Monte Carlo (MC) simulations. The potential of using the recently proposed ∆E-E filter for removing nuclear interactions that occurred in the energy/range detector of the pCT system is investigated.Full pCT scans were acquired with the TOPAS MC simulated version of the prototype scanner that comprises two tracking detectors and a 5 stage energy/range detector. An ideal water cylinder and a water cylinder with 5 tissue inserts were investigated. Before image reconstruction, a 3 σ WEPL filter was applied as the only filter, or in addition to filters acting on the energy deposit in each of the energy detector stages, as done currently with the prototype. The potential of the ∆E-E filter that was recently proposed for helium imaging was assessed. The results were compared to simulations for which nuclear interactions were disabled representing ground truth.The 3 σ WEPL filter alone was not sufficient to filter out all nuclear interaction events and systematic fluctuations in the form of ring artifacts were present in the pCT reconstructed images. Applying energy filters currently used with the device prior to the 3 σ WEPL filter only slightly improved the image quality. A 2 σ WEPL filter improved the mean RSP accuracy, but could not

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“…A calibration procedure that transforms the detector single‐proton measurement to WEPL is necessary and is discussed in Bashkirov et al The pCT collaboration has developed an improved version in which a polystyrene wedge phantom is used in Ref. [] instead of the stepped pyramid phantom. In addition to the wedge, four polystyrene blocks are required to bring the proton Bragg peak into each stage of the five‐stage plastic scintillator detector …”

Section: Methodsmentioning

confidence: 99%

Experimental fluence‐modulated proton computed tomography by pencil beam scanning

et al. 2018

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Results from a Prototype Proton-CT Head Scanner

Cited by 26 publications

References 11 publications

Experimental comparison of proton CT and dual energy x-ray CT for relative stopping power estimation in proton therapy

Experimental comparison of proton CT and dual energy x-ray CT for relative stopping power estimation in proton therapy

Improving single-event proton CT by removing nuclear interaction events within the energy/range detector

Experimental fluence‐modulated proton computed tomography by pencil beam scanning

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