Stability and linearity of luminescence imaging of water during irradiation of proton-beams and X-ray photons lower energy than the Cerenkov light threshold

Yamamoto, Seiichi; Koyama, Shuji; Yabe, Takuya; Komori, Masataka; Tada, J.; Ito, Shiori; Toshito, T.; Hirata, Yuho; Watanabe, K.

doi:10.1016/j.nima.2017.11.073

Cited by 18 publications

(22 citation statements)

References 16 publications

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“…The signal reduction at the Bragg peak was anticipated due to spread of the beam spots with increasing water depth and the 1 mm diameter of the fibre. The interpretation of fluorescence is in agreement with other sources (Peeples et al 2012, Yamamoto et al 2018 reporting of a strong correlation between luminescence and dose profile as water is irradiated with photons or protons below theČerenkov threshold.…”

Section: Transition Radiationsupporting

confidence: 90%

Quenching-free fluorescence signal from plastic-fibres in proton dosimetry: understanding the influence of Čerenkov radiation

Christensen¹,

Almhagen²,

Nyström³

et al. 2018

Phys. Med. Biol.

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The origin of photons emitted in optical fibres under proton irradiation has been attributed to either entirely Čerenkov radiation or light consisting of fluorescence with a substantial amount of Čerenkov radiation. The source of the light emission is assessed in order to understand why the signal from optical fibres irradiated with protons is reportedly quenching-free. The present study uses the directional emittance of Čerenkov photons in 12 MeV and 20 MeV electron beams to validate a Monte Carlo model for simulating the emittance and transmission of Čerenkov radiation in optical fibres. We show that fewer than 0.01 Čerenkov photons are emitted and guided per 225 MeV proton penetrating the optical fibre, and that the Čerenkov signal in the optical fibre is completely negligible at the Bragg peak. Furthermore, on taking the emittance and guidance of both fluorescence and Čerenkov photons into account, it becomes evident that the reported quenching-free signal in PMMA-based optical fibres during proton irradiation is due to fluorescence.

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Section: Transition Radiationsupporting

confidence: 90%

Quenching-free fluorescence signal from plastic-fibres in proton dosimetry: understanding the influence of Čerenkov radiation

Christensen¹,

Almhagen²,

Nyström³

et al. 2018

Phys. Med. Biol.

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“…Recently, we found the luminescence of water at a lower energy than the CL threshold for protons, 20 carbon ions, 21 alpha particles, 22 beta particles, 23 and low-energy x-ray. 24 The luminescence of water at a lower energy than the CL threshold has linearity to energy 25 and shows a distribution that is identical to the dose in protons. 26 We also found that the optical photon production of the luminescence of water is ∼0.1 photons∕MeV, by comparing the experimental results with those of the simulation.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the fractions of luminescence of water at higher energy than Cerenkov-light threshold for various types of radiation

Hirano

Yamamoto

2019

J. Biomed. Opt.

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Although the luminescence of water at a lower energy than the Cerenkov-light (CL) threshold has been found for various types of radiation, the fractions of the luminescence of water to the total produced light have not been obvious for radiations at a higher energy than the CL threshold because it is difficult to separate these two types of light. Thus, we used a Monte Carlo simulation to estimate the fractions of the luminescence of water for various types of radiation at a higher energy than the CL threshold to confirm the major component of the produced light. After we confirmed that the estimated light production of the luminescence of water could adequately simulate the experimental results, we calculated the produced light photons of this luminescence and the CL from water for protons (170 MeV), carbon ions (330 MeV/n), high-energy x-ray (6 MV) from a linear accelerator (LINAC), high-energy electrons (9 MeV) from LINAC, positrons (F-18, C-11, O-15, and N-13), and high-energy gamma photon radionuclides (Co-60). For protons, the major fraction of the produced light was the luminescence of water in addition to the CL from the prompt gamma photons produced by the nuclear interactions. For carbon ions, the major fraction of the produced light was the luminescence of water and the CL produced by the secondary electrons in addition to the prompt gamma photons produced by the nuclear interactions. For high-energy x-ray and electrons from LINAC, the fractions of luminescence of water were ∼0.1% to 0.2%. The fractions of luminescence of water for positrons were 0.2% to 1.5% and that for Co-60 was 0.4%. We conclude that the major fractions of light produced from x-ray and electrons from LINAC, positron radionuclides, and the Co-60 source are CL, with fractions of the luminescence of water from <0.1% to 1.5%.

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“…Ionization and production of luminescence in air is also generally a well-documented phenomenon and is primarily attributed to atmospheric nitrogen [32,33]. Lastly, x-ray photons were also demonstrated in the luminescence imaging of water at sub-Cerenkov-threshold energy levels [30,31] and the emitted luminescence was found to be proportional to the x-ray energy. In particular, this generation of optical photons with low energy x-rays is of particular concern or interest for XLI/XLCT imaging.…”

Section: Introductionmentioning

confidence: 94%

“…The signal generation in XLCT is a form of radioluminescence where the ionizing radiation (in this case, x-ray photons) causes the emission of optical photons from the embedded contrast agents, and it is generally assumed that all the optical photons generated are emitted only from the contrast agents. However, numerous studies have reported other sources of optical photons from the radioluminescence of air, water, and biological tissue [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] at energies below the Cerenkov radiation threshold which will provide background noise and limit the molecular sensitivity of XLCT imaging. Yamamoto et al conducted various luminescence imaging experiments with different sources of radiation to image both water and air.…”

Section: Introductionmentioning

confidence: 99%

“…Yamamoto et al conducted various luminescence imaging experiments with different sources of radiation to image both water and air. Using proton-beam irradiation, they found that water was able to luminesce even during traditional proton-therapy, and determined that this information could be useful for dose and range estimation [20][21][22][23]30]. With carbon-ion irradiation, they performed similar luminescence imaging (also with energy below the Cerenkov-threshold) and determined, by measuring and deriving the light spectra, that this water luminescence was likely caused by an electromagnetic pulse produced from the dipole displacement inside water molecules as the derived spectra was found to be proportional to λ −2.0 [24,25].…”

Section: Introductionmentioning

confidence: 99%

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Background luminescence in x-ray luminescence computed tomography (XLCT) imaging

Lun

2019

Appl. Opt.

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X-ray luminescence computed tomography (XLCT) is an emerging hybrid imaging modality. It has been recently reported that materials like water, tissue, or even air can generate optical photons upon x-ray irradiation which can increase the noises in measurements of XLCT. In this study, we have investigated the x-ray luminescence from water, air, as well as tissue mimicking phantoms, including one embedded with a 0.01 mg/mL GOS:Eu 3+ microphosphor target. We have measured the optical emission spectrum from each sample, including samples of meat and fat, using a spectrograph. Our results indicate that there are plenty of optical photons emitted by x-ray irradiation and a small nanophosphor concentration, as low as 5.28 μM in a deep background can provide enough contrast for XLCT imaging.

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Stability and linearity of luminescence imaging of water during irradiation of proton-beams and X-ray photons lower energy than the Cerenkov light threshold

Cited by 18 publications

References 16 publications

Quenching-free fluorescence signal from plastic-fibres in proton dosimetry: understanding the influence of Čerenkov radiation

Quenching-free fluorescence signal from plastic-fibres in proton dosimetry: understanding the influence of Čerenkov radiation

Estimation of the fractions of luminescence of water at higher energy than Cerenkov-light threshold for various types of radiation

Background luminescence in x-ray luminescence computed tomography (XLCT) imaging

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