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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. |
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Title |
A practical MRI-based reconstruction method for a new endocavitary and interstitial gynaecological template |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of Contemporary Brachytherapy |
Abbreviated Journal  |
J. Contemp. Brachytherapy |
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Volume |
7 |
Issue |
5 |
Pages |
407-414 |
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Keywords |
brachytherapy template; catheter reconstruction; gynecological template; interstitial implants |
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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. |
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Address |
[Richart, Jose; Otal, Antonio; Rodriguez, Silvia; DePiaggio, Marina; Santos, Manuel; Perez-Calatayud, Jose] Benidorm Hosp, Dept Radiotherapy, Alicante, Spain, Email: fballest@uv.es |
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Publisher |
Termedia Publishing House Ltd |
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English |
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ISSN |
1689-832x |
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Conference |
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Notes |
WOS:000365247600012 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2476 |
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Author |
Candela-Juan, C.; Ballester, F.; Perez-Calatayud, J.; Vijande, J. |
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Title |
Assaying multiple I-125 seeds with the well-ionization chamber SourceCheck(4 Pi) 33005 and a new insert |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of Contemporary Brachytherapy |
Abbreviated Journal |
J. Contemp. Brachytherapy |
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Volume |
7 |
Issue |
6 |
Pages |
492-496 |
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Keywords |
brachytherapy; insert; quality assurance; prostate; seeds; well chamber |
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Abstract |
Purpose: To provide a practical solution that can be adopted in clinical routine to fulfill the AAPM-ESTRO recommendations regarding quality assurance of seeds used in prostate permanent brachytherapy. The aim is to design a new insert for the well-ionization chamber SourceCheck(4 Pi) 33005 (PTW, Germany) that allows evaluating the mean air-kerma strength of up to ten I-125 seeds with one single measurement instead of measuring each seed individually. Material and methods: The material required is: a) the SourceCheck(4 Pi) 33005 well-ionization chamber provided with a PTW insert to measure the air-kerma strength S-K of one single seed at a time; b) a newly designed insert that accommodates ten seeds in one column, which allows measuring the mean S-K of the ten seeds in one single measurement; and c) a container with ten seeds from the same batch and class of the seeds used for the patient implant, and a set of nine non-radioactive seeds.The new insert is characterized by determining its calibration coefficient, used to convert the reading of the well-chamber when ten seeds are measured to their mean S-K. The proposed method is validated by comparing the mean S-K of the ten seeds obtained from the new insert with the individual measurement of S-K of each seed, evaluated with the PTW insert. Results: The ratio between the calibration coefficient of the new insert and the calibration coefficient of the PTW insert for the SourceCheck(4 Pi) 33005 is 1.135 +/- 0.007 (k = 1). The mean S-K of a set of ten seeds evaluated with this new system is in agreement with the mean value obtained from measuring independently the S-K of each seed. Conclusions: The new insert and procedure allow evaluating the mean S-K of ten seeds prior to the implant in a single measurement. The method is faster and more efficient from radiation protection point of view than measuring the individual S-K of each seed. |
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Address |
[Candela-Juan, Cristian; Perez-Calatayud, Jose] La Fe Univ, Dept Radiat Oncol, Phys Sect, E-46026 Valencia, Spain, Email: ccanjuan@gmail.com |
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Termedia Publishing House Ltd |
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English |
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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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Expedition |
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Conference |
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Notes |
WOS:000368381300010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2533 |
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Author |
Pujades, M.C.; Granero, D.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Papagiannis, P.; Siebert, F.A. |
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Title |
Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities |
Type |
Journal Article |
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Year |
2014 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
34 |
Issue |
4 |
Pages |
741-753 |
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Keywords |
bunker; shielding; NCRP 151; brachytherapy; Monte Carlo |
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Abstract |
In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for Ir-192 and Co-60 HDR applications to account for several different bunker layouts. For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by Ir-192 and Co-60 will reduce the lead thickness by a factor of five for Ir-192 and ten for Co-60. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers. The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness. |
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Address |
[Pujades, M. C.] Natl Ctr Dosimetry CND, Valencia, Spain, Email: mpuclau@gmail.com |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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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 |
0952-4746 |
ISBN |
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Conference |
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Notes |
WOS:000345895800005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2031 |
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Author |
Palomo, R.; Pujades, M.C.; Gimeno-Olmos, J.; Carmona, V.; Lliso, F.; Candela-Juan, C.; Vijande, J.; Ballester, F.; Perez-Calatayud, J. |
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Title |
Evaluation of lens absorbed dose with Cone Beam IGRT procedures |
Type |
Journal Article |
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Year |
2015 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
35 |
Issue |
4 |
Pages |
N33-N41 |
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Keywords |
IGRT; CBCT; lens absorbed dose; TLD |
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Abstract |
The purpose of this work is to evaluate the absorbed dose to the eye lenses due to the cone beam computed tomography (CBCT) system used to accurately position the patient during head-and-neck image guided procedures. The on-board imaging (OBI) systems (v. 1.5) of Clinac iX and TrueBeam (Varian) accelerators were used to evaluate the imparted dose to the eye lenses and some additional points of the head. All CBCT scans were acquired with the Standard-Dose Head protocol from Varian. Doses were measured using thermoluminescence dosimeters (TLDs) placed in an anthropomorphic phantom. TLDs were calibrated at the beam quality used to reduce their energy dependence. Average dose to the lens due to the OBI systems of the Clinac iX and the TrueBeam were 0.71 +/- 0.07 mGy/CBCT and 0.70 +/- 0.08 mGy/CBCT, respectively. The extra absorbed dose received by the eye lenses due to one CBCT acquisition with the studied protocol is far below the 500 mGy threshold established by ICRP for cataract formation (ICRP 2011 Statement on Tissue Reactions). However, the incremental effect of several CBCT acquisitions during the whole treatment should be taken into account. |
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Address |
[Palomo, R.; Gimeno-Olmos, J.; Carmona, V.; Lliso, F.; Candela-Juan, C.; Perez-Calatayud, J.] La Fe Univ, Dept Radiotherapy, Phys Sect, E-46026 Valencia, Spain, Email: mpuclau@gmail.com |
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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 |
0952-4746 |
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:000366388500002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2494 |
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Author |
Gimenez-Alventosa, V.; Vijande, J.; Ballester, F.; Perez-Calatayud, J. |
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Title |
Transit dose comparisons for Co-60 and Ir-192 HDR sources |
Type |
Journal Article |
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Year |
2016 |
Publication |
Journal of Radiological Protection |
Abbreviated Journal |
J. Radiol. Prot. |
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Volume |
36 |
Issue |
4 |
Pages |
858-864 |
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Keywords |
Monte Carlo; dosimetry; HDR brachytherapy; transit dose |
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Abstract |
The goal of this study is to evaluate the ambient dose due to the transit of high dose rate (HDR) Co-60 sources along a transfer tube as compared to Ir-192 ones in a realistic clinical scenario. This goal is accomplished by evaluating air-kerma differences with Monte Carlo calculations using PENELOPE2011. Scatter from both the afterloader and the patient was not taken into account. Two sources, mHDR-v2 and Flexisource Co-60, (Elekta Brachytherapy, Veenendaal, the Netherlands) have been considered. These sources were simulated within a standard transfer tube located in an infinite air phantom. The movement of the source was included by displacing their positions along the connecting tube from z = – 75 cm to z = + 75 cm and combining them. Since modern afterloaders like Flexitron (Elekta) or Saginova (BEBIG GmbH) are able to use equally 192Ir and 60Co sources, it was assumed that both sources are displaced with equal speed. Typical HDR source activity content values were provided by the manufacturer. 2D distributions were obtained with type-A uncertainties (k = 2) less than 0.01%. From those, the air-kerma ratio Co-60/Ir-192 was evaluated weighted by their corresponding typical activities. It was found that it varies slowly with distance (less than 10% variation at 75 cm) but strongly in time due to the shorter half-life of the 192Ir (73.83 d). The maximum ratio is located close to the tube. It reaches a value of 0.57 when the typical activity of the sources at the time when they were installed by the vendor was used. Such ratio increases up to 1.28 at the end of the recommended working life (90 d) of the Ir-192 source. Co-60/Ir-192 air-kerma ratios are almost constant (0.51-0.57) in the vicinity of the source-tube with recent installed sources. Nevertheless, air-kerma ratios increase rapidly (1.15-1.29) whenever the Ir-192 is approaching the end of its life. In case of a medical event requiring the medical staff to access the treatment room, these ratios indicate that the dosimetric impact on the medical team will be lower, with a few exceptions, in the case of Co-60-based HDR brachytherapy as compared to Ir-192-based one when typical air-kerma strength values are considered. |
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Address |
[Gimenez-Alventosa, Vicent; Vijande, Javier; Ballester, Facundo] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: javier.vijande@uv.es |
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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 |
0952-4746 |
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:000386436100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2839 |
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