A generalized model for monitor units determination in ocular proton therapy using machine learning:A proof-of-concept study

Objective. Determining and verifying the number of monitor units is crucial to achieving the desired dose distribution in radiotherapy and maintaining treatment efficacy. However, current commercial treatment planning system(s) dedicated to ocular passive eyelines in proton therapy do not provide the number of monitor units for patient-specific plan delivery. Performing specific pre-treatment field measurements, which is time and resource consuming, is usually gold-standard practice. This proof-of-concept study reports on the development of a multi-institutional-based generalized model for monitor units determination in proton therapy for eye melanoma treatments. Approach. To cope with the small number of patients being treated in proton centers, three European institutes participated in this study. Measurements data were collected to address output factor differences across the institutes, especially as function of field size, spread-out Bragg peak modulation width, residual range, and air gap. A generic model for monitor units prediction using a large number of 3748 patients and broad diversity in tumor patterns, was evaluated using six popular machine learning algorithms: (i) decision tree; (ii) random forest, (iii) extra trees, (iv) K-nearest neighbors, (v) gradient boosting, and (vi) the support vector regression. Features used as inputs into each machine learning pipeline were: Spread-out Bragg peak width, range, air gap, fraction and calibration doses. Performance measure was scored using the mean absolute error, which was the difference between predicted and real monitor units, as collected from institutional gold-standard methods. Main results. Predictions across algorithms were accurate within 3% uncertainty for up to 85.2% of the plans and within 10% uncertainty for up to 98.6% of the plans with the extra trees algorithm. Significance. A proof-of-concept of using machine learning-based generic monitor units determination in ocular proton therapy has been demonstrated. This could trigger the development of an independent monitor units calculation tool for clinical use.</p

A generalized model for monitor units determination in ocular proton therapy using machine learning:A proof-of-concept study

Objective. Determining and verifying the number of monitor units is crucial to achieving the desired dose distribution in radiotherapy and maintaining treatment efficacy. However, current commercial treatment planning system(s) dedicated to ocular passive eyelines in proton therapy do not provide the number of monitor units for patient-specific plan delivery. Performing specific pre-treatment field measurements, which is time and resource consuming, is usually gold-standard practice. This proof-of-concept study reports on the development of a multi-institutional-based generalized model for monitor units determination in proton therapy for eye melanoma treatments. Approach. To cope with the small number of patients being treated in proton centers, three European institutes participated in this study. Measurements data were collected to address output factor differences across the institutes, especially as function of field size, spread-out Bragg peak modulation width, residual range, and air gap. A generic model for monitor units prediction using a large number of 3748 patients and broad diversity in tumor patterns, was evaluated using six popular machine learning algorithms: (i) decision tree; (ii) random forest, (iii) extra trees, (iv) K-nearest neighbors, (v) gradient boosting, and (vi) the support vector regression. Features used as inputs into each machine learning pipeline were: Spread-out Bragg peak width, range, air gap, fraction and calibration doses. Performance measure was scored using the mean absolute error, which was the difference between predicted and real monitor units, as collected from institutional gold-standard methods. Main results. Predictions across algorithms were accurate within 3% uncertainty for up to 85.2% of the plans and within 10% uncertainty for up to 98.6% of the plans with the extra trees algorithm. Significance. A proof-of-concept of using machine learning-based generic monitor units determination in ocular proton therapy has been demonstrated. This could trigger the development of an independent monitor units calculation tool for clinical use.</p

Zastosowanie detektorów śladowych w pomiarach parametrów fizycznych i dozymetrycznych wybranych pól promieniowania jonizującego : rozprawa doktorska /

Recenzenci pracy: Urszula Woźnicka, Stefan Taczanowski.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2006.Bibliogr. k. 144-154.Ogólna charakterystyka detektorów śladowych, oddziaływanie cząstek naładowanych z materią, wpływ promieniowania jonizującego na polimery, teorie formowania się śladu, struktura utajonego śladu, trawienie, czynniki mające wpływ na proces trawienia, geometria przy stałej wartości VT, zmiennej, promieniowanie kosmiczne, skład, oddziaływanie promieniowania kosmicznego z polem magnetycznym Ziemi, z atmosferą, czynniki wpływające na poziom promieniowania kosmicznego w atmosferze, dawki promieniowania kosmicznego w atmosferze, poza atmosferą, spalacyjne źródła neutronów, reakcja spalacji ciężkich jąder, wybrane zagadnienia konstrukcji źródeł spalacyjnych, systemy energetyczne sterowane akceleratorem, materiały, metody eksperymentalne, definicje wybranych wielkości, detektory śladowe zastosowane w pomiarach, trawienie, odczyt detektorów, wielkości mierzone, pole powierzchni obrazu, gęstość śladów, długości osi, prędkość trawienia plastiku VB, kąt padania cząstki, odpowiedź kątowa detektora, stosunek prędkości trawień V, krytyczny kąt padania cząstki, gęstość śladów na powierzchni detektora pozostającego w kontakcie ze źródłem fragmentów rozszczepienia, definicje wybranych wielkości dozymetrycznych, fluencja, liniowy przekaz energii, dawka pochłonięta, wielkości dozymetryczne dla napromienienia zewnętrznego, oprogramowanie, pomiary dawek promieniowania kosmicznego w samolotach pasażerskich, kalibracja detektorów, ekspozycje w samolotach, spektrometria LET ciężkich jonów, ekspozycje kalibracyjne, kontrola trawienia, zależność LET(V), kąt krytyczny dla wybranych jonów, w funkcji fluencji padających jonów, pomiary dawek w polach nieznanych jonów, wewnątrz, w otoczeniu tarczy spalacyjnej, widma protonów, neutronów wewnątrz, za tarczą spalacyjną, wskazania detektorów śladowych, pęd przekazany przez cząstkę rozszczepiającą do rozszczepianego jądra, wpływ pędu przekazanego do rozszczepianego jądra na pęd, energię kinetyczną, zasięg fragmentów rozszczepienia w radiatorach, anizotropia emisji fragmentów rozszczepienia, wpływ przekazu pędu cząstki rozszczepiającej, anizotropii na rozkład kątów, wydajność detekcji fragmentów rozszczepienia w detektorach Axpet, Vivak, gęstość rozszczepień jąder radiatorów metalicznych, energia efektywna pola promieniowania, pomiary w pierwotnej wiązce protonó

NUNDO: a numerical model of a human torso phantom and its application to effective dose equivalent calculations for astronauts at the ISS

The health effects of cosmic radiation on astronauts need to be precisely quantified and controlled. This task is important not only in perspective of the increasing human presence at the International Space Station (ISS), but also for the preparation of safe human missions beyond low earth orbit. From a radiation protection point of view, the baseline quantity for radiation risk assessment in space is the effective dose equivalent. The present work reports the first successful attempt of the experimental determination of the effective dose equivalent in space, both for extra-vehicular activity (EVA) and intra-vehicular activity (IVA). This was achieved using the anthropomorphic torso phantom RANDO® equipped with more than 6,000 passive thermoluminescent detectors and plastic nuclear track detectors, which have been exposed to cosmic radiation inside the European Space Agency MATROSHKA facility both outside and inside the ISS. In order to calculate the effective dose equivalent, a numerical model of the RANDO® phantom, based on computer tomography scans of the actual phantom, was developed. It was found that the effective dose equivalent rate during an EVA approaches 700 μSv/d, while during an IVA about 20 % lower values were observed. It is shown that the individual dose based on a personal dosimeter reading for an astronaut during IVA results in an overestimate of the effective dose equivalent of about 15 %, whereas under an EVA conditions the overestimate is more than 200 %. A personal dosemeter can therefore deliver quite good exposure records during IVA, but may overestimate the effective dose equivalent received during an EVA considerably

Ambient dose equivalent measurements in secondary radiation fields at proton therapy facility CCB IFJ PAN in Krakow using recombination chambers

This work presents recombination methods used for secondary radiation measurements at the Facility for Proton Radiotherapy of Eye Cancer at the Institute for Nuclear Physics, IFJ, in Krakow (Poland). The measurements of H*(10) were performed, with REM-2 tissue equivalent chamber in two halls of cyclotrons AIC-144 and Proteus C-235 and in the corridors close to treatment rooms. The measurements were completed by determination of gamma radiation component, using a hydrogen-free recombination chamber. The results were compared with the measurements using rem meter types FHT 762 (WENDI-II) and NM2 FHT 192 gamma probe and with stationary dosimetric system

DOSIS & DOSIS 3D: long-term dose monitoring onboard the Columbus Laboratory of the International Space Station (ISS)

The radiation environment encountered in space differs in nature from that on Earth, consisting mostly of highly energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones present on Earth for occupational radiation workers. Since the beginning of the space era, the radiation exposure during space missions has been monitored with various active and passive radiation instruments. Also onboard the International Space Station (ISS), a number of area monitoring devices provide data related to the spatial and temporal variation of the radiation field in and outside the ISS. The aim of the DOSIS (2009–2011) and the DOSIS 3D (2012–ongoing) experiments was and is to measure the radiation environment within the European Columbus Laboratory of the ISS. These measurements are, on the one hand, performed with passive radiation detectors mounted at 11 locations within Columbus for the determination of the spatial distribution of the radiation field parameters and, on the other, with two active radiation detectors mounted at a fixed position inside Columbus for the determination of the temporal variation of the radiation field parameters. Data measured with passive radiation detectors showed that the absorbed dose values inside the Columbus Laboratory follow a pattern, based on the local shielding configuration of the radiation detectors, with minimum dose values observed in the year 2010 of 195–270 lGy/day and maximum values observed in the year 2012 with values ranging from 260 to 360 lGy/day. The absorbed dose is modulated by (a) the variation in solar activity and (b) the changes in ISS altitude

THE DOSIS 3D PROJECT ON-BOARD THE INTERNATIONAL SPACE STATION – STATUS AND SCIENCE OVERVIEW OF 8 YEARS OF MEASUREMENTS (2012 – 2020)

The radiation environment encountered in space differs in nature from that on Earth, consisting mostly of highly energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones present on Earth for occupational radiation workers. Since the beginning of the space era the radiation exposure during space missions has been monitored with various passive and active radiation instruments. Also on-board the International Space Station (ISS) a number of area monitoring devices provide data related to the spatial and temporal variation of the radiation field in – and outside the ISS. The aim of the DOSIS 3D (2012 - ongoing) experiment is the measurement of the radiation environment within the European Columbus Laboratory of the ISS. These measurements are, on the one hand, performed with passive radiation detectors mounted at eleven locations within Columbus for the determination of the spatial distribution of the radiation field parameters and, on the other hand, with two active radiation detectors (DOSTEL) mounted at a fixed position inside Columbus for the determination of the temporal variation of the radiation field parameters. The talk will give an overview of the current results of the data evaluation performed for the passive and active radiation detectors for DOSIS 3D in the years 2012 to 2020 and further focus on the work in progress for data comparison with other passive and active radiation detector systems measuring on-board the ISS

DOSIS & DOSIS 3D: long-term dose monitoring onboard the Columbus Laboratory of the International Space Station (ISS)

The radiation environment encountered in space differs in nature from that on Earth, consisting mostly of highly energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones present on Earth for occupational radiation workers. Since the beginning of the space era, the radiation exposure during space missions has been monitored with various active and passive radiation instruments. Also onboard the International Space Station (ISS), a number of area monitoring devices provide data related to the spatial and temporal variation of the radiation field in and outside the ISS. The aim of the DOSIS (2009–2011) and the DOSIS 3D (2012–ongoing) experiments was and is to measure the radiation environment within the European Columbus Laboratory of the ISS. These measurements are, on the one hand, performed with passive radiation detectors mounted at 11 locations within Columbus for the determination of the spatial distribution of the radiation field parameters and, on the other, with two active radiation detectors mounted at a fixed position inside Columbus for the determination of the temporal variation of the radiation field parameters. Data measured with passive radiation detectors showed that the absorbed dose values inside the Columbus Laboratory follow a pattern, based on the local shielding configuration of the radiation detectors, with minimum dose values observed in the year 2010 of 195–270 μGy/day and maximum values observed in the year 2012 with values ranging from 260 to 360 μGy/day. The absorbed dose is modulated by (a) the variation in solar activity and (b) the changes in ISS altitude