A Simulation Study on Estimation of Bragg-Peak Shifts via Machine Learning Using Proton-Beam Images Obtained by Measurement of Secondary Electron Bremsstrahlung

Proton beam therapy (PBT) is a curative treatment for hepatocellular carcinoma (HCC), because it can preserve liver function due to dose targeting via the Bragg peak. However, the degree of direct liver damage by PBT is unclear. In this study, we retrospectively analyzed liver/biliary enzymes and total bilirubin (T-Bil) as markers of direct liver damage during and early after PBT in 300 patients. The levels of these enzymes and bilirubin were almost stable throughout the treatment period. In patients with normal pretreatment levels, aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), and T-Bil were abnormally elevated in only 2 (1.2%), 1 (0.4%), 0, 2 (1.2%), and 8 (3.5%) patients, respectively, and in 8 of these 13 patients (61.5%) the elevations were temporary. In patients with abnormal pretreatment levels, the levels tended to decrease during PBT. GGT and T-Bil were elevated by 1.62 and 1.57 times in patients who received 66 Gy (RBE) in 10 fractions and 74 Gy (RBE) in 37 fractions, respectively, but again these changes were temporary. These results suggest that direct damage to normal liver caused by PBT is minimal, even if a patient has abnormal pretreatment enzyme levels.

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Sensitivity improvement of YAP(Ce) cameras for imaging of secondary electron bremsstrahlung x-rays emitted during carbon-ion irradiation: problem and solution

Physics in Medicine and Biology ◽

10.1088/1361-6560/ab7a6e ◽

2020 ◽

Vol 65 (10) ◽

pp. 105008 ◽

Cited By ~ 1

Author(s):

Seiichi Yamamoto ◽

Mitsutaka Yamaguchi ◽

Takashi Akagi ◽

Maki Kitano ◽

Naoki Kawachi

Keyword(s):

Secondary Electron ◽

Ion Irradiation ◽

X Rays ◽

Carbon Ion ◽

Electron Bremsstrahlung ◽

Sensitivity Improvement

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An Entropy-Based Machine Learning Algorithm for Combining Macroeconomic Forecasts

Entropy ◽

10.3390/e21101015 ◽

2019 ◽

Vol 21 (10) ◽

pp. 1015 ◽

Cited By ~ 3

Author(s):

Carles Bretó ◽

Priscila Espinosa ◽

Penélope Hernández ◽

Jose M. Pavía

Keyword(s):

Machine Learning ◽

Gross Domestic Product ◽

Maximum Entropy ◽

Simulation Study ◽

Learning Algorithm ◽

Predictive Ability ◽

Learning Approach ◽

Machine Learning Algorithm ◽

Machine Learning Approach ◽

Maximum Entropy Inference

This paper applies a Machine Learning approach with the aim of providing a single aggregated prediction from a set of individual predictions. Departing from the well-known maximum-entropy inference methodology, a new factor capturing the distance between the true and the estimated aggregated predictions presents a new problem. Algorithms such as ridge, lasso or elastic net help in finding a new methodology to tackle this issue. We carry out a simulation study to evaluate the performance of such a procedure and apply it in order to forecast and measure predictive ability using a dataset of predictions on Spanish gross domestic product.

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The Radiobiological Effects of Proton Beam Therapy: Impact on DNA Damage and Repair

Cancers ◽

10.3390/cancers11070946 ◽

2019 ◽

Vol 11 (7) ◽

pp. 946 ◽

Cited By ~ 15

Author(s):

Eirini Terpsi Vitti ◽

Jason L Parsons

Keyword(s):

Dna Damage ◽

Dna Repair ◽

Proton Beam ◽

Bragg Peak ◽

Proton Beam Therapy ◽

High Energy ◽

High Let ◽

Repair Pathways ◽

Radiobiological Effects ◽

Photon Radiotherapy

Proton beam therapy (PBT) offers significant benefit over conventional (photon) radiotherapy for the treatment of a number of different human cancers, largely due to the physical characteristics. In particular, the low entrance dose and maximum energy deposition in depth at a well-defined region, the Bragg peak, can spare irradiation of proximal healthy tissues and organs at risk when compared to conventional radiotherapy using high-energy photons. However, there are still biological uncertainties reflected in the relative biological effectiveness that varies along the track of the proton beam as a consequence of the increases in linear energy transfer (LET). Furthermore, the spectrum of DNA damage induced by protons, particularly the generation of complex DNA damage (CDD) at high-LET regions of the distal edge of the Bragg peak, and the specific DNA repair pathways dependent on their repair are not entirely understood. This knowledge is essential in understanding the biological impact of protons on tumor cells, and ultimately in devising optimal therapeutic strategies employing PBT for greater clinical impact and patient benefit. Here, we provide an up-to-date review on the radiobiological effects of PBT versus photon radiotherapy in cells, particularly in the context of DNA damage. We also review the DNA repair pathways that are essential in the cellular response to PBT, with a specific focus on the signaling and processing of CDD induced by high-LET protons.

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