| Records |
| 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 |
| 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:000457182500004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3897 |
| Permanent link to this record |
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| Author |
Richart, J.; Otal, A.; Rodriguez, S.; Nicolas, A.I.; DePiaggio, M.; Santos, M.; Vijande, J.; Ballester, F.; Perez-Calatayud, J. |
| Title |
A practical MRI-based reconstruction method for a new endocavitary and interstitial gynaecological template |
Type |
Journal Article |
| Year |
2015 |
Publication |
Journal of Contemporary Brachytherapy |
Abbreviated Journal |
J. Contemp. Brachytherapy |
| Volume |
7 |
Issue |
5 |
Pages |
407-414 |
| Keywords |
brachytherapy template; catheter reconstruction; gynecological template; interstitial implants |
| Abstract |
Purpose: There are perineal templates for interstitial implants such as MUPIT and Syed applicators. Their limitations are the intracavitary component deficit and the necessity to use computed tomography (CT) for treatment planning since both applicators are non-magnetic resonance imaging (MRI) compatibles. To overcome these problems, a new template named Template Benidorm (TB) has been recently developed. Titanium needles are usually reconstructed based on their own artifacts, mainly in T1-weighted sequence, using the void on the tip as the needle tip position. Nevertheless, patient tissues surrounding the needles present heterogeneities that complicate the accurate identification of these artifact patterns. The purpose of this work is to improve the titanium needle reconstruction uncertainty for the TB case using a simple method based on the free needle lengths and typical MRI pellets markers. Material and methods: The proposed procedure consists on the inclusion of three small A-vitamin pellets (hyper-intense on MRI images) compressed by both applicator plates defining the central plane of the plate's arrangement. The needles used are typically 20 cm in length. For each needle, two points are selected defining the straight line. From such line and the plane equations, the intersection can be obtained, and using the free length (knowing the offset distance), the coordinates of the needle tip can be obtained. The method is applied in both T1W and T2W acquisition sequences. To evaluate the inter-observer variation of the method, three implants of T1W and another three of T2W have been reconstructed by two different medical physicists with experience on these reconstructions. Results and conclusions: The differences observed in the positioning were significantly smaller than 1 mm in all cases. The presented algorithm also allows the use of only T2W sequence either for contouring or reconstruction purposes. The proposed method is robust and independent of the visibility of the artifact at the tip of the needle. |
| Address |
[Richart, Jose; Otal, Antonio; Rodriguez, Silvia; DePiaggio, Marina; Santos, Manuel; Perez-Calatayud, Jose] Benidorm Hosp, Dept Radiotherapy, Alicante, Spain, Email: fballest@uv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Termedia Publishing House 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 |
1689-832x |
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:000365247600012 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
2476 |
| Permanent link to this record |
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| Author |
Rodriguez-Alvarez, M.J.; Sanchez, F.; Soriano, A.; Iborra, A. |
| Title |
Sparse Givens resolution of large system of linear equations: Applications to image reconstruction |
Type |
Journal Article |
| Year |
2010 |
Publication |
Mathematical and Computer Modelling |
Abbreviated Journal |
Math. Comput. Model. |
| Volume |
52 |
Issue |
7-8 |
Pages |
1258-1264 |
| Keywords |
Givens rotations; QR-factorization; Computed tomography; Image reconstruction |
| Abstract |
In medicine, computed tomographic images are reconstructed from a large number of measurements of X-ray transmission through the patient (projection data). The mathematical model used to describe a computed tomography device is a large system of linear equations of the form AX = B. In this paper we propose the QR decomposition as a direct method to solve the linear system. QR decomposition can be a large computational procedure. However, once it has been calculated for a specific system, matrices Q and R are stored and used for any acquired projection on that system. Implementation of the QR decomposition in order to take more advantage of the sparsity of the system matrix is discussed. |
| Address |
[Rodriguez-Alvarez, Maria-Jose; Iborra, Amadeo] Univ Politecn Valencia, Inst Matemat Multidisciplinar, E-46022 Valencia, Spain, Email: mjrodri@imm.upv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Pergamon-Elsevier Science 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 |
0895-7177 |
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 |
ISI:000280933700043 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ elepoucu @ |
Serial |
395 |
| Permanent link to this record |
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| Author |
Albiol, F.; Corbi, A.; Albiol, A. |
| Title |
Geometrical Calibration of X-Ray Imaging With RGB Cameras for 3D Reconstruction |
Type |
Journal Article |
| Year |
2016 |
Publication |
IEEE Transactions on Medical Imaging |
Abbreviated Journal |
IEEE Trans. Med. Imaging |
| Volume |
35 |
Issue |
8 |
Pages |
1952-1961 |
| Keywords |
3D reconstruction; camera system; geometric calibration; visible fiducials; X-ray imaging |
| Abstract |
We present a methodology to recover the geometrical calibration of conventional X-ray settings with the help of an ordinary video camera and visible fiducials that are present in the scene. After calibration, equivalent points of interest can be easily identifiable with the help of the epipolar geometry. The same procedure also allows the measurement of real anatomic lengths and angles and obtains accurate 3D locations from image points. Our approach completely eliminates the need for X-ray-opaque reference marks (and necessary supporting frames) which can sometimes be invasive for the patient, occlude the radiographic picture, and end up projected outside the imaging sensor area in oblique protocols. Two possible frameworks are envisioned: a spatially shifting X-ray anode around the patient/object and a moving patient that moves/rotates while the imaging system remains fixed. As a proof of concept, experiences with a device under test (DUT), an anthropomorphic phantom and a real brachytherapy session have been carried out. The results show that it is possible to identify common points with a proper level of accuracy and retrieve three-dimensional locations, lengths and shapes with a millimetric level of precision. The presented approach is simple and compatible with both current and legacy widespread diagnostic X-ray imaging deployments and it can represent a good and inexpensive alternative to other radiological modalities like CT. |
| Address |
[Albiol, Francisco; Corbi, Alberto] Univ Valencia, Consejo Super Invest Cient, Inst Fis Corpuscular IFIC, Paterna 46980, Spain, Email: kiko@ific.uv.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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 |
0278-0062 |
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:000381436000016 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
2781 |
| Permanent link to this record |
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| Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
| Title |
A fast algorithm for muon track reconstruction and its application to the ANTARES neutrino telescope |
Type |
Journal Article |
| Year |
2011 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
| Volume |
34 |
Issue |
9 |
Pages |
652-662 |
| Keywords |
Neutrino telescope; Track reconstruction |
| Abstract |
An algorithm is presented, that provides a fast and robust reconstruction of neutrino induced upward-going muons and a discrimination of these events from downward-going atmospheric muon background in data collected by the ANTARES neutrino telescope. The algorithm consists of a hit merging and hit selection procedure followed by fitting steps for a track hypothesis and a point-like light source. It is particularly well-suited for real time applications such as online monitoring and fast triggering of optical follow-up observations for multi-messenger studies. The performance of the algorithm is evaluated with Monte Carlo simulations and various distributions are compared with that obtained in ANTARES data. |
| Address |
[Carminati, G.] Leiden Univ, NL-2300 RA Leiden, Netherlands, Email: brunner@ifh.de |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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 |
0927-6505 |
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 |
ISI:000289329100002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
608 |
| Permanent link to this record |
