| Records |
| Author |
Aguiar, P.; Rafecas, M.; Ortuño, J.E.; Kontaxakis, G.; Santos, A.; Pavia, J.; Rosetti, M. |
| Title |
Geometrical and Monte Carlo projectors in 3D PET reconstruction |
Type |
Journal Article |
| Year |
2010 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
37 |
Issue |
11 |
Pages |
5691-5702 |
| Keywords |
3D PET; iterative reconstruction; list-mode reconstruction; ray-tracing techniques; Monte Carlo simulation; system response matrix |
Abstract  |
Purpose: In the present work, the authors compare geometrical and Monte Carlo projectors in detail. The geometrical projectors considered were the conventional geometrical Siddon ray-tracer (S-RT) and the orthogonal distance-based ray-tracer (OD-RT), based on computing the orthogonal distance from the center of image voxel to the line-of-response. A comparison of these geometrical projectors was performed using different point spread function (PSF) models. The Monte Carlo-based method under consideration involves an extensive model of the system response matrix based on Monte Carlo simulations and is computed off-line and stored on disk. Methods: Comparisons were performed using simulated and experimental data of the commercial small animal PET scanner rPET. Results: The results demonstrate that the orthogonal distance-based ray-tracer and Siddon ray-tracer using PSF image-space convolutions yield better images in terms of contrast and spatial resolution than those obtained after using the conventional method and the multiray-based S-RT. Furthermore, the Monte Carlo-based method yields slight improvements in terms of contrast and spatial resolution with respect to these geometrical projectors. Conclusions: The orthogonal distance-based ray-tracer and Siddon ray-tracer using PSF image-space convolutions represent satisfactory alternatives to factorizing the system matrix or to the conventional on-the-fly ray-tracing methods for list-mode reconstruction, where an extensive modeling based on Monte Carlo simulations is unfeasible. |
| Address |
[Aguiar, Pablo] Univ Santiago de Compostela, Dept Fis Particulas, Complexo Hosp Univ Santiago de Compostela, Fdn IDICHUS IDIS, Santiago De Compostela, Spain, Email: pablo.aguiar.fernandez@sergas.es |
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| Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
Place of Publication |
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| Language |
English |
Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0094-2405 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
ISI:000283747600015 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ elepoucu @ |
Serial |
338 |
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| Author |
Baran, J. et al; Brzezinski, K. |
| Title |
Feasibility of the J-PET to monitor the range of therapeutic proton beams |
Type |
Journal Article |
| Year |
2024 |
Publication |
Physica Medica |
Abbreviated Journal |
Phys. Medica |
| Volume |
118 |
Issue |
|
Pages |
103301 - 9pp |
| Keywords |
PET; Range monitoring; J-PET; Monte Carlo simulations; Proton radiotherapy |
| Abstract |
Purpose: The aim of this work is to investigate the feasibility of the Jagiellonian Positron Emission Tomography (J -PET) scanner for intra-treatment proton beam range monitoring. Methods: The Monte Carlo simulation studies with GATE and PET image reconstruction with CASToR were performed in order to compare six J -PET scanner geometries. We simulated proton irradiation of a PMMA phantom with a Single Pencil Beam (SPB) and Spread -Out Bragg Peak (SOBP) of various ranges. The sensitivity and precision of each scanner were calculated, and considering the setup's cost-effectiveness, we indicated potentially optimal geometries for the J -PET scanner prototype dedicated to the proton beam range assessment. Results: The investigations indicate that the double -layer cylindrical and triple -layer double -head configurations are the most promising for clinical application. We found that the scanner sensitivity is of the order of 10-5 coincidences per primary proton, while the precision of the range assessment for both SPB and SOBP irradiation plans was found below 1 mm. Among the scanners with the same number of detector modules, the best results are found for the triple -layer dual -head geometry. The results indicate that the double -layer cylindrical and triple -layer double -head configurations are the most promising for the clinical application, Conclusions: We performed simulation studies demonstrating that the feasibility of the J -PET detector for PET -based proton beam therapy range monitoring is possible with reasonable sensitivity and precision enabling its pre -clinical tests in the clinical proton therapy environment. Considering the sensitivity, precision and cost-effectiveness, the double -layer cylindrical and triple -layer dual -head J -PET geometry configurations seem promising for future clinical application. |
| Address |
[Baran, Jakub; Silarski, Michal; Chug, Neha; Coussat, Aurelien; Czerwinski, Eryk; Dadgar, Meysam; Dulski, Kamil; Eliyan, Kavya, V; Gajos, Aleksander; Kacprzak, Krzysztof; Kaplon, Lukasz; Korcyl, Grzegorz; Kozik, Tomasz; Kumar, Deepak; Niedzwiecki, Szymon; Panek, Dominik; Parzych, Szymon; del Rio, Elena Perez; Simbarashe, Moyo; Sharma, Sushil; Shivani; Skurzok, Magdalena; Stepien, Ewa L.; Tayefi, Keyvan; Tayefi, Faranak; Moskal, Pawel] Jagiellonian Univ, Fac Phys Astron & Appl Comp Sci, 11 Lojasiewicza St, PL-30348 Krakow, Poland, Email: jakubbaran92@gmail.com |
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| Publisher |
Elsevier Sci Ltd |
Place of Publication |
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English |
Summary Language |
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Series Title |
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Series Issue |
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Edition |
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| ISSN |
1120-1797 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001178648400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5990 |
| Permanent link to this record |
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| Author |
Candela-Juan, C.; Niatsetski, Y.; van der Laarse, R.; Granero, D.; Ballester, F.; Perez-Calatayud, J.; Vijande, J. |
| Title |
Design and characterization of a new high-dose-rate brachytherapy Valencia applicator for larger skin lesions |
Type |
Journal Article |
| Year |
2016 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
43 |
Issue |
4 |
Pages |
1639-1648 |
| Keywords |
skin applicator; Valencia applicator; HDR brachytherapy; dosimetry; Monte Carlo |
| Abstract |
Purpose: The aims of this study were (i) to design a new high-dose-rate (HDR) brachytherapy applicator for treating surface lesions with planning target volumes larger than 3 cm in diameter and up to 5 cm in size, using the microSelectron-HDR or Flexitron afterloader (Elekta Brachytherapy) with a Ir-192 source; (ii) to calculate by means of the Monte Carlo (MC) method the dose distribution for the new applicator when it is placed against a water phantom; and (iii) to validate experimentally the dose distributions in water. Methods: The PENELOPE2008 MC code was used to optimize dwell positions and dwell times. Next, the dose distribution in a water phantom and the leakage dose distribution around the applicator were calculated. Finally, MC data were validated experimentally for a 192Ir mHDR-v2 source by measuring (i) dose distributions with radiochromic EBT3 films (ISP); (ii) percentage depth-dose (PDD) curve with the parallel-plate ionization chamber Advanced Markus (PTW); and (iii) absolute dose rate with EBT3 films and the PinPoint T31016 (PTW) ionization chamber. Results: The new applicator is made of tungsten alloy (Densimet) and consists of a set of interchangeable collimators. Three catheters are used to allocate the source at prefixed dwell positions with preset weights to produce a homogenous dose distribution at the typical prescription depth of 3 mm in water. The same plan is used for all available collimators. PDD, absolute dose rate per unit of air kerma strength, and off-axis profiles in a cylindrical water phantom are reported. These data can be used for treatment planning. Leakage around the applicator was also scored. The dose distributions, PDD, and absolute dose rate calculated agree within experimental uncertainties with the doses measured: differences of MC data with chamber measurements are up to 0.8% and with radiochromic films are up to 3.5%. Conclusions: The new applicator and the dosimetric data provided here will be a valuable tool in clinical practice, making treatment of large skin lesions simpler, faster, and safer. Also the dose to surrounding healthy tissues is minimal. |
| Address |
[Candela-Juan, C.; Perez-Calatayud, J.] La Fe Univ & Polytech Hosp, Dept Radiat Oncol, Valencia 46026, Spain, Email: ccanjuan@gmail.com |
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| Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0094-2405 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
|
| Notes |
WOS:000373711000007 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2620 |
| Permanent link to this record |
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| Author |
Oliver, S.; Gimenez-Alventosa, V.; Berumen, F.; Gimenez, V.; Beaulieu, L.; Ballester, F.; Vijande, J. |
| Title |
Benchmark of the PenRed Monte Carlo framework for HDR brachytherapy |
Type |
Journal Article |
| Year |
2023 |
Publication |
Zeitschrift für Medizinische Physik |
Abbreviated Journal |
Z. Med. Phys. |
| Volume |
33 |
Issue |
4 |
Pages |
511-528 |
| Keywords |
Monte Carlo; PenRed; Brachytherapy; DICOM; Medical physics |
| Abstract |
Purpose: The purpose of this study is to validate the PenRed Monte Carlo framework for clinical applications in brachytherapy. PenRed is a C++ version of Penelope Monte Carlo code with additional tallies and utilities. Methods and materials: Six benchmarking scenarios are explored to validate the use of PenRed and its improved bachytherapy-oriented capabilities for HDR brachytherapy. A new tally allowing the evaluation of collisional kerma for any material using the track length kerma estimator and the possibility to obtain the seed positions, weights and directions processing directly the DICOM file are now implemented in the PenRed distribution. The four non-clinical test cases developed by the Joint AAPM-ESTRO-ABG-ABS WG-DCAB were evaluated by comparing local and global absorbed dose differences with respect to established reference datasets. A prostate and a palliative lung cases, were also studied. For them, absorbed dose ratios, global absorbed dose differences, and cumulative dose-volume histograms were obtained and discussed. Results: The air-kerma strength and the dose rate constant corresponding to the two sources agree with the reference datatests within 0.3% (Sk) and 0.1% (K). With respect to the first three WG-DCAB test cases, more than 99.8% of the voxels present local (global) differences within +/- 1%(+/- 0.1%) of the reference datasets. For test Case 4 reference dataset, more than 94.9%(97.5%) of voxels show an agreement within +/- 1%(+/- 0.1%), better than similar benchmarking calculations in the literature. The track length kerma estimator scorer implemented increases the numerical efficiency of brachytherapy calculations two orders of magnitude, while the specific brachytherapy source allows the user to avoid the use of error-prone intermediate steps to translate the DICOM information into the simulation. In both clinical cases, only minor absorbed dose differences arise in the low-dose isodoses. 99.8% and 100% of the voxels have a global absorbed dose difference ratio within +/- 0.2%for the prostate and lung cases, respectively. The role played by the different segmentation and composition material in the bone structures was discussed, obtaining negligible absorbed dose differ-ences. Dose-volume histograms were in agreement with the reference data.Conclusions: PenRed incorporates new tallies and utilities and has been validated for its use for detailed and precise high-dose-rate brachytherapy simulations. |
| Address |
[Oliver, S.] Univ Politecn Valencia, Inst Segur Ind, Radiofis & Medioambiental ISIRYM, Camide Vera s n, Valencia 46022, Spain, Email: sanolgi@upvnet.upv.es |
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Thesis |
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| Publisher |
Elsevier |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0939-3889 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001137118400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5885 |
| Permanent link to this record |
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| Author |
Fletcher, E.M.; Ballester, F.; Beaulieu, L.; Morrison, H.; Poher, A.; Rivard, M.J.; Sloboda, R.S.; Vijande, J.; Thomson, R.M. |
| Title |
Generation and comparison of 3D dosimetric reference datasets for COMS eye plaque brachytherapy using model-based dose calculations |
Type |
Journal Article |
| Year |
2024 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
51 |
Issue |
|
Pages |
694-706 |
| Keywords |
Monte Carlo; ocular brachytherapy; treatment planning |
| Abstract |
PurposeA joint Working Group of the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) was created to aid in the transition from the AAPM TG-43 dose calculation formalism, the current standard, to model-based dose calculations. This work establishes the first test cases for low-energy photon-emitting brachytherapy using model-based dose calculation algorithms (MBDCAs).Acquisition and Validation MethodsFive test cases are developed: (1) a single model 6711 125I brachytherapy seed in water, 13 seeds (2) individually and (3) in combination in water, (4) the full Collaborative Ocular Melanoma Study (COMS) 16-mm eye plaque in water, and (5) the full plaque in a realistic eye phantom. Calculations are done with four Monte Carlo (MC) codes and a research version of a commercial treatment planning system (TPS). For all test cases, local agreement of MC codes was within & SIM;2.5% and global agreement was & SIM;2% (4% for test case 5). MC agreement was within expected uncertainties. Local agreement of TPS with MC was within 5% for test case 1 and & SIM;20% for test cases 4 and 5, and global agreement was within 0.4% for test case 1 and 10% for test cases 4 and 5.Data Format and Usage NotesDose distributions for each set of MC and TPS calculations are available online () along with input files and all other information necessary to repeat the calculations.Potential ApplicationsThese data can be used to support commissioning of MBDCAs for low-energy brachytherapy as recommended by TGs 186 and 221 and AAPM Report 372. This work additionally lays out a sample framework for the development of test cases that can be extended to other applications beyond eye plaque brachytherapy. |
| Address |
[Fletcher, Elizabeth M.; Thomson, Rowan M.] Carleton Univ, Phys Dept, Carleton Lab Radiotherapy Phys, Ottawa, ON, Canada, Email: rthomson@physics.carleton.ca |
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Thesis |
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| Publisher |
Wiley |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0094-2405 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:001058112300001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5632 |
| Permanent link to this record |
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| Author |
Ma, Y.Z.; Vijande, J.; Ballester, F.; Tedgren, A.C.; Granero, D.; Haworth, A.; Mourtada, F.; Fonseca, G.P.; Zourari, K.; Papagiannis, P.; Rivard, M.J.; Siebert, F.A.; Sloboda, R.S.; Smith, R.; Chamberland, M.J.P.; Thomson, R.M.; Verhaegen, F.; Beaulieu, L. |
| Title |
A generic TG-186 shielded applicator for commissioning model-based dose calculation algorithms for high-dose-rate Ir-192 brachytherapy |
Type |
Journal Article |
| Year |
2017 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
44 |
Issue |
11 |
Pages |
5961-5976 |
| Keywords |
Ir-192; HDR brachytherapy; model based dose calculation; Monte Carlo methods; shielded applicator; TG-186 |
| Abstract |
PurposeA joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform calculations and comparisons with model-based dose calculation algorithms (MBDCAs). Its main goal is to facilitate a smooth transition from the AAPM Task Group No. 43 (TG-43) dose calculation formalism, widely being used in clinical practice for brachytherapy, to the one proposed by Task Group No. 186 (TG-186) for MBDCAs. To do so, in this work a hypothetical, generic high-dose rate (HDR) Ir-192 shielded applicator has been designed and benchmarked. MethodsA generic HDR Ir-192 shielded applicator was designed based on three commercially available gynecological applicators as well as a virtual cubic water phantom that can be imported into any DICOM-RT compatible treatment planning system (TPS). The absorbed dose distribution around the applicator with the TG-186 Ir-192 source located at one dwell position at its center was computed using two commercial TPSs incorporating MBDCAs (Oncentra((R)) Brachy with Advanced Collapsed-cone Engine, ACE, and BrachyVision ACUROS) and state-of-the-art Monte Carlo (MC) codes, including ALGEBRA, BrachyDose, egs_brachy, Geant4, MCNP6, and Penelope2008. TPS-based volumetric dose distributions for the previously reported source centered in water and source displaced test cases, and the new source centered in applicator test case, were analyzed here using the MCNP6 dose distribution as a reference. Volumetric dose comparisons of TPS results against results for the other MC codes were also performed. Distributions of local and global dose difference ratios are reported. ResultsThe local dose differences among MC codes are comparable to the statistical uncertainties of the reference datasets for the source centered in water and source displaced test cases and for the clinically relevant part of the unshielded volume in the source centered in applicator case. Larger local differences appear in the shielded volume or at large distances. Considering clinically relevant regions, global dose differences are smaller than the local ones. The most disadvantageous case for the MBDCAs is the one including the shielded applicator. In this case, ACUROS agrees with MC within [-4.2%, +4.2%] for the majority of voxels (95%) while presenting dose differences within [-0.12%, +0.12%] of the dose at a clinically relevant reference point. For ACE, 95% of the total volume presents differences with respect to MC in the range [-1.7%, +0.4%] of the dose at the reference point. ConclusionsThe combination of the generic source and generic shielded applicator, together with the previously developed test cases and reference datasets (available in the Brachytherapy Source Registry), lay a solid foundation in supporting uniform commissioning procedures and direct comparisons among treatment planning systems for HDR Ir-192 brachytherapy. |
| Address |
[Ma, Yunzhi; Beaulieu, Luc] CHU Quebec, Dept Radio Oncol & Axe Oncol, Ctr Rech, Quebec City, PQ G1R 2J6, Canada, Email: yunzhi.Ma@crchuq.ulaval.ca |
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Thesis |
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| Publisher |
Wiley |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0094-2405 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000414970800039 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3370 |
| Permanent link to this record |
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| Author |
Peppa, V.; Thomson, R.M.; Enger, S.A.; Fonseca, G.P.; Lee, C.N.; Lucero, J.N.E.; Mourtada, F.; Siebert, F.A.; Vijande, J.; Papagiannis, P. |
| Title |
A MC-based anthropomorphic test case for commissioning model-based dose calculation in interstitial breast 192-Ir HDR brachytherapy |
Type |
Journal Article |
| Year |
2023 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
50 |
Issue |
7 |
Pages |
4675-4687 |
| Keywords |
anthropomorphic phantom; commissioning; HDR brachytherapy; model based dose calculation algorithms; Monte Carlo |
| Abstract |
PurposeTo provide the first clinical test case for commissioning of Ir-192 brachytherapy model-based dose calculation algorithms (MBDCAs) according to the AAPM TG-186 report workflow. Acquisition and Validation MethodsA computational patient phantom model was generated from a clinical multi-catheter Ir-192 HDR breast brachytherapy case. Regions of interest (ROIs) were contoured and digitized on the patient CT images and the model was written to a series of DICOM CT images using MATLAB. The model was imported into two commercial treatment planning systems (TPSs) currently incorporating an MBDCA. Identical treatment plans were prepared using a generic Ir-192 HDR source and the TG-43-based algorithm of each TPS. This was followed by dose to medium in medium calculations using the MBDCA option of each TPS. Monte Carlo (MC) simulation was performed in the model using three different codes and information parsed from the treatment plan exported in DICOM radiation therapy (RT) format. Results were found to agree within statistical uncertainty and the dataset with the lowest uncertainty was assigned as the reference MC dose distribution. Data Format and Usage NotesThe dataset is available online at ,. Files include the treatment plan for each TPS in DICOM RT format, reference MC dose data in RT Dose format, as well as a guide for database users and all files necessary to repeat the MC simulations. Potential ApplicationsThe dataset facilitates the commissioning of brachytherapy MBDCAs using TPS embedded tools and establishes a methodology for the development of future clinical test cases. It is also useful to non-MBDCA adopters for intercomparing MBDCAs and exploring their benefits and limitations, as well as to brachytherapy researchers in need of a dosimetric and/or a DICOM RT information parsing benchmark. Limitations include specificity in terms of radionuclide, source model, clinical scenario, and MBDCA version used for its preparation. |
| Address |
[Peppa, Vasiliki; Papagiannis, Panagiotis] Natl & Kapodistrian Univ Athens, Med Sch, Med Phys Lab, Athens, Greece, Email: ppapagi@med.uoa.gr |
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Thesis |
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| Publisher |
Wiley |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0094-2405 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000989616100001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5529 |
| Permanent link to this record |
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| Author |
Calatayud-Jordan, J.; Candela-Juan, C.; Palma, J.D.; Pujades-Claumarchirant, M.C.; Soriano, A.; Gracia-Ochoa, M.; Vilar-Palop, J.; Vijande, J. |
| Title |
Influence of the simultaneous calibration of multiple ring dosimeters on the individual absorbed dose |
Type |
Journal Article |
| Year |
2021 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
| Volume |
41 |
Issue |
2 |
Pages |
384-397 |
| Keywords |
ring dosimeters; personal dosimetry; calibration; Monte Carlo; ISO 4037 |
| Abstract |
Ring dosimeters for personal dosimetry are calibrated in accredited laboratories following ISO 4037-3 guidelines. The simultaneous irradiation of multiple dosimeters would save time, but has to be carefully studied, since the scattering conditions could change and influence the absorbed dose in nearby dosimeters. Monte Carlo simulations using PENELOPE-2014 were performed to explore the need to increase the uncertainty of H-p (0.07) in the simultaneous irradiation of three and five DXT-RAD 707H-2 (Thermo Scientific) ring dosimeters with beam qualities: N-30, N-80 and N-300. Results show that the absorbed dose in each dosimeter is compatible with each of the others and with the reference simulation (a single dosimeter), with a coverage probability of 95% (k = 2). Comparison with experimental data yielded consistent results with the same coverage probability. Therefore, five ring dosimeters can be simultaneously irradiated with beam qualities ranging, at least, between N-30 and N-300 with a negligible impact on the uncertainty of H-p (0.07). |
| Address |
[Calatayud-Jordan, J.] Hosp Univ Politecn La Fe, Valencia, Spain, Email: calatayud_josjor@gva.es |
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Thesis |
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| Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0952-4746 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
WOS:000657114600001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
4850 |
| Permanent link to this record |
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| Author |
Etxebeste, A.; Barrio, J.; Bernabeu, J.; Lacasta, C.; Llosa, G.; Muñoz, E.; Ros, A.; Oliver, J.F. |
| Title |
Study of sensitivity and resolution for full ring PET prototypes based on continuous crystals and analytical modeling of the light distribution |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
| Volume |
64 |
Issue |
3 |
Pages |
035015 - 17pp |
| Keywords |
continuous crystals; NEMA NU 4-2008; positron emission tomography (PET); Monte Carlo simulations; image reconstruction; depth of interaction |
| Abstract |
Sensitivity and spatial resolution are the main parameters to maximize in the performance of a PET scanner. For this purpose, detectors consisting of a combination of continuous crystals optically coupled to segmented photodetectors have been employed. With the use of continuous crystals the sensitivity is increased with respect to the pixelated crystals. In addition, spatial resolution is no longer limited to the crystal size. The main drawback is the difficulty in determining the interaction position. In this work, we present the characterization of the performance of a full ring based on cuboid continuous crystals coupled to SiPMs. To this end, we have employed the simulations developed in a previous work for our experimental detector head. Sensitivity could be further enhanced by using tapered crystals. This enhancement is obtained by increasing the solid angle coverage, reducing the wedge-shaped gaps between contiguous detectors. The performance of the scanners based on both crystal geometries was characterized following NEMA NU 4-2008 standardized protocol in order to compare them. An average sensitivity gain over the entire axial field of view of 13.63% has been obtained with tapered geometry while similar performance of the spatial resolution has been proven with both scanners. The activity at which NECR and true peak occur is smaller and the peak value is greater for tapered crystals than for cuboid crystals. Moreover, a higher degree of homogeneity was obtained in the sensitivity map due to the tighter packing of the crystals, which reduces the gaps and results in a better recovery of homogeneous regions than for the cuboid configuration. Some of the results obtained, such as spatial resolution, depend on the interaction position estimation and may vary if other method is employed. |
| Address |
[Etxebeste, Ane; Barrio, John; Bernabeu, Jose; Lacasta, Carlos; Llosa, Gabriela; Munoz, Enrique; Ros, Ana; Oliver, Josef F.] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: ane.etxebeste@ific.uv.es |
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| Publisher |
Iop Publishing Ltd |
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| Language |
English |
Summary Language |
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Edition |
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| ISSN |
0031-9155 |
ISBN |
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Conference |
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| Notes |
WOS:000457182500004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3897 |
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| Author |
Gimenez-Alventosa, V.; Antunes, P.C.G.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Andreo, P. |
| Title |
Collision-kerma conversion between dose-to-tissue and dose-to-water by photon energy-fluence corrections in low-energy brachytherapy |
Type |
Journal Article |
| Year |
2017 |
Publication |
Physics in Medicine and Biology |
Abbreviated Journal |
Phys. Med. Biol. |
| Volume |
62 |
Issue |
1 |
Pages |
146-164 |
| Keywords |
Monte Carlo; dosimetry; low-energy seed; collision-kerma; mass energy-absorption coefficients; energy-fluence correction factor |
| Abstract |
The AAPM TG-43 brachytherapy dosimetry formalism, introduced in 1995, has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations, except in the vicinity of the source capsule. Subsequent dosimetry developments, based on Monte Carlo calculations or analytical solutions of transport equations, do not rely on the CPE assumption and determine directly the dose to different tissues. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seeds is proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences. State-of-the art Monte Carlo calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone), which in all cases include a realistic modelling of low-energy brachytherapy sources in order to benchmark the formalism proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases (e.g. bone tissue). |
| Address |
[Gimenez-Alventosa, Vicent; Antunes, Paula C. G.; Vijande, Javier; Ballester, Facundo] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: vijande@uv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0031-9155 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000391567700001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2923 |
| Permanent link to this record |
