Spot scanning proton therapy minimizes neutron dose in the setting of radiation therapy administered during pregnancy

Wang, Xin; Poenisch, Falk; Zhu, Ronald X.; Lii, M.; Gillin, Michael; Li, Jing; Grosshans, David R.

doi:10.1120/jacmp.v17i5.6327

Cited by 18 publications

(24 citation statements)

References 29 publications

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“…The observed secondary cancer incidence at 10 years was significantly decreased from 8.6% with photons to 5.4% with protons (Hazard ratio of 0.54; p <0.09). Importantly protons were delivered to patients with a passive scattering delivery paradigm that produced more neutrons than PBS (46,47). The latter delivery may thus produce even less radiation-induced malignancies.…”

Section: Discussionmentioning

confidence: 99%

Proton Therapy for Intracranial Meningioma for the Treatment of Primary/Recurrent Disease Including Re-Irradiation

et al. 2020

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Meningeal tumors represent approximately 10–25% of primary brain tumors and occur usually in elderly female patients. Most meningiomas are benign (80–85%) and for symptomatic and/or large tumors, surgery, with or without radiation therapy (RT), has been long established as an effective means of local tumor control. RT can be delivered to inoperable lesions or to those with non-benign histology and for Simpson I–III and IV–V resection. RT can be delivered with photons or particles (protons or carbon ions) in stereotactic or non-stereotactic conditions. Particle therapy delivered for these tumors uses the physical properties of charged carbon ions or protons to spare normal brain tissue (i.e. Bragg peak), with or without or a dose-escalation paradigm for non-benign lesions. PT can substantially decrease the dose delivered to the non-target brain tissues, including but not limited to the hippocampi, optic apparatus or cochlea. Only a limited number of meningioma patients have been treated with PT in the adjuvant or recurrent setting, as well as for inoperable lesions with pencil beam scanning and with protons only. Approximately 500 patients with image-defined or WHO grade I meningioma have been treated with protons. The reported outcome, usually 5-year local tumor control, ranges from 85 to 99% (median, 96%). For WHO grade II or III patients, the outcome of only 97 patients has been published, reporting a median tumor local control rate of 52% (range, 38–71.1). Only 24 recurring patients treated previously with photon radiotherapy and re-treated with PT were reported. The clinical outcome of these challenging patients seems interesting, provided that they presented initially with benign tumors, are not in the elderly category and have been treated previously with conventional radiation dose of photons. Overall, the number of meningioma patients treated or-re-irradiated with this treatment modality is small and the clinical evidence level is somewhat low (i.e. 3b–5). In this review, we detail the results of upfront PT delivered to patients with meningioma in the adjuvant setting and for inoperable tumors. The outcome of meningioma patients treated with this radiation modality for recurrent tumors, with or without previous RT, will also be reviewed.

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Section: Discussionmentioning

confidence: 99%

Proton Therapy for Intracranial Meningioma for the Treatment of Primary/Recurrent Disease Including Re-Irradiation

et al. 2020

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“…171 The subject of the out-offield dose is also related to the treatment of pregnant patients and patients with implanted cardiac pacemakers and defibrillators. Published data on the comparative out-of-field dose from proton therapy are helpful for the assessment, 168,[172][173][174][175] and the management of proton therapy patients with implanted cardiac pacemakers and defibrillators is specifically addressed in TG-203. 176…”

Section: Out-of-field Dose From Proton Therapymentioning

confidence: 99%

Clinical commissioning of intensity‐modulated proton therapy systems: Report of AAPM Task Group 185

Farr¹,

Moyers²,

Allgower

et al. 2020

Medical Physics

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Proton therapy is an expanding radiotherapy modality in the United States and worldwide. With the number of proton therapy centers treating patients increasing, so does the need for consistent, high-quality clinical commissioning practices. Clinical commissioning encompasses the entire proton therapy system's multiple components, including the treatment delivery system, the patient positioning system, and the image-guided radiotherapy components. Also included in the commissioning process are the x-ray computed tomography scanner calibration for proton stopping power, the radiotherapy treatment planning system, and corresponding portions of the treatment management system. This commissioning report focuses exclusively on intensitymodulated scanning systems, presenting details of how to perform the commissioning of the proton therapy and ancillary systems, including the required proton beam measurements, treatment planning system dose modeling, and the equipment needed.

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“…Although passive irradiation was mainstream in those days, scanning irradiation has become the method of today. Several studies reported that the neutron dose by scanning method is much lower by an order of one or two than that by passive method . Thus, taking 1/10 as a typical value of neutron dose by scanning irradiation compared to that by passive irradiation, the number of malfunctions by particle beams is reduced as additionally drawn in Fig.…”

Section: Discussionmentioning

confidence: 84%

Prediction of radiation‐induced malfunction for cardiac implantable electronic devices (CIEDs)

Matsubara¹,

Ezura²,

Hashimoto³

et al. 2020

Medical Physics

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Purpose Cardiac implantable electronic devices (CIEDs) were believed to possess a tolerance dose to malfunction during radiotherapy. Although recent studies have qualitatively suggested neutrons as a cause of malfunction, numerical understanding has not been reached. The purpose of this work is to quantitatively clarify the contribution of secondary neutrons from out‐of‐field irradiation to the malfunction of CIEDs as well as to deduce the frequency of malfunctions until completion of prostate cancer treatment as a typical case. Materials and Methods Measured data were gathered from the literature and were re‐analyzed. Firstly, linear relationship for a number of malfunctions to the neutron dose was suggested by theoretical consideration. Secondly, the accumulated number of malfunctions of CIEDs gathered from the literature was compared with the prescribed dose, scattered photon dose, and secondary neutron dose for analysis of their correlation. Thirdly, the number of malfunctions during a course of prostate treatment with high‐energy X‐ray, passive proton, and passive carbon‐ion beams was calculated while assuming the same response to malfunctions, where X‐rays consisted of 6‐MV, 10‐MV, 15‐MV, and 18‐MV beams. Monte Carlo simulation assuming simple geometry was performed for the distribution of neutron dose from X‐ray beams, where normalization factors were applied to the distribution so as to reproduce the empirical values. Results Linearity between risk and neutron dose was clearly found from the measured data, as suggested by theoretical consideration. The predicted number of malfunctions until treatment completion was 0, 0.02 ± 0.01, 0.30 ± 0.08, 0.65 ± 0.17, 0.88 ± 0.50, and 0.14 ± 0.04 when 6‐MV, 10‐MV, 15‐MV, 18‐MV, passive proton, and passive carbon‐ion beams, respectively, were employed, where the single model response to a malfunction of 8.6 ± 2.1 Sv−1 was applied. Conclusions Numerical understanding of the malfunction of CIEDs has been attained for the first time. It has been clarified that neutron dose is a good scale for the risk of CIEDs in radiotherapy. Prediction of the frequency of malfunction as well as discussion of the risk to CIEDs in radiotherapy among the multiple modalities have become possible. Because the present study quantitatively clarifies the neutron contribution to malfunction, revision of clinical guidelines is suggested.

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Spot scanning proton therapy minimizes neutron dose in the setting of radiation therapy administered during pregnancy

Cited by 18 publications

References 29 publications

Proton Therapy for Intracranial Meningioma for the Treatment of Primary/Recurrent Disease Including Re-Irradiation

Proton Therapy for Intracranial Meningioma for the Treatment of Primary/Recurrent Disease Including Re-Irradiation

Clinical commissioning of intensity‐modulated proton therapy systems: Report of AAPM Task Group 185

Prediction of radiation‐induced malfunction for cardiac implantable electronic devices (CIEDs)

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