TY  - CONF
AU  - Kojić, Andrea
AU  - Kržanović, Nikola
AU  - Živanović, Miloš
AU  - Božović, Predrag
AU  - Stanković Petrović, Jelena
AU  - Komatina, Ivana
AU  - Vlahović, Jelena
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11909
AB  - Ionization chambers and solid state detectors incorporated into multimeters are often used for quality control in different modalities of medical imaging and diagnostic radiology. The equipment to be used in the routine QC procedures needs to be calibrated under well-known radiation conditions (known as radiation qualities) defined by the international standards. International standards IEC 61267:2005 [IEC 62167, IEC 2005] and IAEA TRS 457:2007 [IAEA TRS 457, IAEA 2007] cover general radiography and fluoroscopy radiation qualities (abbreviated as RQR and RQA series, in the voltage range from 40 kV to 150 kV), and computerized tomography radiation qualities (abbreviated as RQT series, in the voltage range from 100 kV to 150 kV), among other. In the field of mammography reference radiation fields are defined for molybdenum anode/filtration combination (Mo/Mo, abbreviated as RQR-M series, in the voltage range from 25 kV to 35 kV). Since Mo/Mo mammography units are widespread and available at hospitals they have been included in the standard [IEC 62167, IEC 2005]. Even so, Secondary Standard Dosimetry Laboratories (SSDLs) that are performing calibrations of QC dosimeters for end-users, rarely have availability of such anode/filtration combination under reference laboratory conditions. SSDLs most often employ X-ray generators with W/Al combinations. Additionally, nowadays many different combinations of anode/filtration are present in mammography units of different manufacturers that are commonly used in the hospitals. Multimeters are often sensitive to spectral changes caused by different anode/filter combination, so it is doubtful that the traceability established for one anode/filter combination can be used to measure doses for another combination. Measurements with different solid state detectors were performed under laboratory conditions with W/Al radiation qualities established in the SSDL. In the future, research will be expanded to clinical conditions in radiation fields produced by mammography units which employ Mo/Mo, Mo/Rh, Rh/Rh, W/Rh and W/Ag. Dosimeter response will be evaluated based on the dependency of 1st HVL which is correlated to radiation output of the X-ray generator (the incident photon spectra).
PB  - Niš : Sievert Association
C3  - RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts
T1  - Solid state detector energy response in W/Al mammography radiation quality series
SP  - 30
EP  - 30
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11909
ER  - 

@conference{
author = "Kojić, Andrea and Kržanović, Nikola and Živanović, Miloš and Božović, Predrag and Stanković Petrović, Jelena and Komatina, Ivana and Vlahović, Jelena",
year = "2023",
abstract = "Ionization chambers and solid state detectors incorporated into multimeters are often used for quality control in different modalities of medical imaging and diagnostic radiology. The equipment to be used in the routine QC procedures needs to be calibrated under well-known radiation conditions (known as radiation qualities) defined by the international standards. International standards IEC 61267:2005 [IEC 62167, IEC 2005] and IAEA TRS 457:2007 [IAEA TRS 457, IAEA 2007] cover general radiography and fluoroscopy radiation qualities (abbreviated as RQR and RQA series, in the voltage range from 40 kV to 150 kV), and computerized tomography radiation qualities (abbreviated as RQT series, in the voltage range from 100 kV to 150 kV), among other. In the field of mammography reference radiation fields are defined for molybdenum anode/filtration combination (Mo/Mo, abbreviated as RQR-M series, in the voltage range from 25 kV to 35 kV). Since Mo/Mo mammography units are widespread and available at hospitals they have been included in the standard [IEC 62167, IEC 2005]. Even so, Secondary Standard Dosimetry Laboratories (SSDLs) that are performing calibrations of QC dosimeters for end-users, rarely have availability of such anode/filtration combination under reference laboratory conditions. SSDLs most often employ X-ray generators with W/Al combinations. Additionally, nowadays many different combinations of anode/filtration are present in mammography units of different manufacturers that are commonly used in the hospitals. Multimeters are often sensitive to spectral changes caused by different anode/filter combination, so it is doubtful that the traceability established for one anode/filter combination can be used to measure doses for another combination. Measurements with different solid state detectors were performed under laboratory conditions with W/Al radiation qualities established in the SSDL. In the future, research will be expanded to clinical conditions in radiation fields produced by mammography units which employ Mo/Mo, Mo/Rh, Rh/Rh, W/Rh and W/Ag. Dosimeter response will be evaluated based on the dependency of 1st HVL which is correlated to radiation output of the X-ray generator (the incident photon spectra).",
publisher = "Niš : Sievert Association",
journal = "RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts",
title = "Solid state detector energy response in W/Al mammography radiation quality series",
pages = "30-30",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11909"
}

Kojić, A., Kržanović, N., Živanović, M., Božović, P., Stanković Petrović, J., Komatina, I.,& Vlahović, J.. (2023). Solid state detector energy response in W/Al mammography radiation quality series. in RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts
Niš : Sievert Association., 30-30.
https://hdl.handle.net/21.15107/rcub_vinar_11909

Kojić A, Kržanović N, Živanović M, Božović P, Stanković Petrović J, Komatina I, Vlahović J. Solid state detector energy response in W/Al mammography radiation quality series. in RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts. 2023;:30-30.
https://hdl.handle.net/21.15107/rcub_vinar_11909 .

Kojić, Andrea, Kržanović, Nikola, Živanović, Miloš, Božović, Predrag, Stanković Petrović, Jelena, Komatina, Ivana, Vlahović, Jelena, "Solid state detector energy response in W/Al mammography radiation quality series" in RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts (2023):30-30,
https://hdl.handle.net/21.15107/rcub_vinar_11909 .

TY  - CONF
AU  - Topalović, Dušan
AU  - Krajinović, Marko
AU  - Vlahović, Jelena
AU  - Kržanović, Nikola
AU  - Božović, Predrag
AU  - Stanković Petrović, Jelena
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11913
AB  - Thermoluminescent dosimetry is a widely used passive dosimetry method for estimating protection quantities i.e. the effective or equivalent dose. When the thermoluminescent dosemeters (TLD) are irradiated, they store the dose information through the processes of ionisation and subsequent trapping of charge carriers. The charge carriers in TLD crystalline material move from the ground state to the higher energy states (trapping centres) that are partially stable at room temperature. By heating the material, charge carriers leave the metastable energy states and recombine at recombination centres, emitting light (glow). The heating procedure gives rise to a glow curve (GC) – the light intensity as a function of temperature and time. By calibrating the TLD reader, the area under the GC is converted to a dose value (e.g., personal dose equivalent, Hp(10)). The shape of the GC depends on the time-temperature profile (TTP) defined for each TLD material separately and may be regular or possess some anomalies. Inspecting the GC shape, as one of quality control measures, is usually conducted qualitatively and performed by trained TLD service staff. Hence, this paper presents the implementation of the machine learning Time Series Forest (TSF) method for the classification of anomalous GCs of LiF:Mg,Ti based TLD. TSF is a tree – ensemble method that combines entropy gain and distance measure for evaluating splits. This method shows significant computational efficiency compared to the well – known one – nearest – neighbour classifier. The dataset used for the TSF method consists of 201 normalized GCs exported by the software supplied with Harshaw 6600 Plus Automated Reader – WinREMS. The dataset is labelled into five different classes: (1) regular shape, (2) spikes at random positions, (3) TLD signal in the low – temperature region, (4) TLD signal in the high – temperature region, and (5) shift of the entire GC to higher temperatures. A random split of the dataset into training and testing in a 70/30 training/test ratio was performed, while the 10 – fold cross – validation was used for the hyperparameter tuning. The results showed that the TSF method can classify four different anomalies for GC with an accuracy of 96% and a macro average F1 score of 96%. According to the obtained results, it is possible to conclude that the TSF is a promising candidate method that could be implemented as a new software package for automated GC quality control within the TLD service
PB  - Niš : Sievert Association
C3  - RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts
T1  - A Time Series Forest Method for automatic classification of anomalous glow curves of LiF:Mg,Ti based thermoluminescent dosemeters
SP  - 31
EP  - 31
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11913
ER  - 

@conference{
author = "Topalović, Dušan and Krajinović, Marko and Vlahović, Jelena and Kržanović, Nikola and Božović, Predrag and Stanković Petrović, Jelena",
year = "2023",
abstract = "Thermoluminescent dosimetry is a widely used passive dosimetry method for estimating protection quantities i.e. the effective or equivalent dose. When the thermoluminescent dosemeters (TLD) are irradiated, they store the dose information through the processes of ionisation and subsequent trapping of charge carriers. The charge carriers in TLD crystalline material move from the ground state to the higher energy states (trapping centres) that are partially stable at room temperature. By heating the material, charge carriers leave the metastable energy states and recombine at recombination centres, emitting light (glow). The heating procedure gives rise to a glow curve (GC) – the light intensity as a function of temperature and time. By calibrating the TLD reader, the area under the GC is converted to a dose value (e.g., personal dose equivalent, Hp(10)). The shape of the GC depends on the time-temperature profile (TTP) defined for each TLD material separately and may be regular or possess some anomalies. Inspecting the GC shape, as one of quality control measures, is usually conducted qualitatively and performed by trained TLD service staff. Hence, this paper presents the implementation of the machine learning Time Series Forest (TSF) method for the classification of anomalous GCs of LiF:Mg,Ti based TLD. TSF is a tree – ensemble method that combines entropy gain and distance measure for evaluating splits. This method shows significant computational efficiency compared to the well – known one – nearest – neighbour classifier. The dataset used for the TSF method consists of 201 normalized GCs exported by the software supplied with Harshaw 6600 Plus Automated Reader – WinREMS. The dataset is labelled into five different classes: (1) regular shape, (2) spikes at random positions, (3) TLD signal in the low – temperature region, (4) TLD signal in the high – temperature region, and (5) shift of the entire GC to higher temperatures. A random split of the dataset into training and testing in a 70/30 training/test ratio was performed, while the 10 – fold cross – validation was used for the hyperparameter tuning. The results showed that the TSF method can classify four different anomalies for GC with an accuracy of 96% and a macro average F1 score of 96%. According to the obtained results, it is possible to conclude that the TSF is a promising candidate method that could be implemented as a new software package for automated GC quality control within the TLD service",
publisher = "Niš : Sievert Association",
journal = "RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts",
title = "A Time Series Forest Method for automatic classification of anomalous glow curves of LiF:Mg,Ti based thermoluminescent dosemeters",
pages = "31-31",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11913"
}

Topalović, D., Krajinović, M., Vlahović, J., Kržanović, N., Božović, P.,& Stanković Petrović, J.. (2023). A Time Series Forest Method for automatic classification of anomalous glow curves of LiF:Mg,Ti based thermoluminescent dosemeters. in RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts
Niš : Sievert Association., 31-31.
https://hdl.handle.net/21.15107/rcub_vinar_11913

Topalović D, Krajinović M, Vlahović J, Kržanović N, Božović P, Stanković Petrović J. A Time Series Forest Method for automatic classification of anomalous glow curves of LiF:Mg,Ti based thermoluminescent dosemeters. in RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts. 2023;:31-31.
https://hdl.handle.net/21.15107/rcub_vinar_11913 .

Topalović, Dušan, Krajinović, Marko, Vlahović, Jelena, Kržanović, Nikola, Božović, Predrag, Stanković Petrović, Jelena, "A Time Series Forest Method for automatic classification of anomalous glow curves of LiF:Mg,Ti based thermoluminescent dosemeters" in RAP 2023 : International conference on radiation applications in Physics, Chemistry, Biology, Medical Sciences, Engineering and Environmental Sciences; Book of abstracts (2023):31-31,
https://hdl.handle.net/21.15107/rcub_vinar_11913 .