| Records |
| Author |
Ballester, F.; Granero, D.; Perez-Calatayud, J.; Venselaar, J.L.M.; Rivard, M.J. |
Title  |
Study of encapsulated Tm-170 sources for their potential use in brachytherapy |
Type |
Journal Article |
| Year |
2010 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
37 |
Issue |
4 |
Pages |
1629-1637 |
| Keywords |
brachytherapy; cancer; dosimetry; prosthetics; radioisotopes; thulium |
| Abstract |
Methods: The authors have assumed a theoretical Tm-170 cylindrical source encapsulated with stainless steel and typical dimensions taken from the currently available HDR Ir-192 brachytherapy sources. The dose-rate distribution was calculated for this source using the GEANT4 Monte Carlo (MC) code considering both photon and electron Tm-170 spectra. The AAPM TG-43 U1 brachytherapy dosimetry parameters were derived. To study general properties of Tm-170 encapsulated sources, spherical sources encapsulated with stainless steel and platinum were also studied. Moreover, the influence of small variations in the active core and capsule dimensions on the dosimetric characteristics was assessed. Treatment times required for a Tm-170 source were compared to those for Ir-192 and Yb-169 for the same contained activity. Results: Due to the energetic beta spectrum and the large electron yield, the bremsstrahlung contribution to the dose was of the same order of magnitude as from the emitted gammas and characteristic x rays. Moreover, the electron spectrum contribution to the dose was significant up to 4 mm from the source center compared to the photon contribution. The dose-rate constant Lambda of the cylindrical source was 1.23 cGy h(-1) U-1. The behavior of the radial dose function showed promise for applications in brachytherapy. Due to the electron spectrum, the anisotropy was large for r < 6 mm. Variations in manufacturing tolerances did not significantly influence the final dosimetry data when expressed in cGy h(-1) U-1. For typical capsule dimensions, maximum reference dose rates of about 0.2, 10, and 2 Gy min(-1) would then be obtained for Tm-170, Ir-192, and Yb-169, respectively, resulting in treatment times greater than those for HDR Ir-192 brachytherapy. Conclusions: The dosimetric characteristics of source designs exploiting the low photon energy of Tm-170 were studied for potential application in HDR-brachytherapy. Dose-rate distributions were obtained for cylindrical and simplified spherical Tm-170 source designs (stainless steel and platinum capsule materials) using MC calculations. Despite the high activity of Tm-170, calculated treatment times were much longer than for Ir-192. |
| Address |
[Ballester, Facundo] Univ Valencia, Dept Atom Mol & Nucl Phys, E-46100 Burjassot, Spain, Email: fballest@uv.es |
| Corporate Author |
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Thesis |
|
| Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0094-2405 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000276211200027 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
478 |
| Permanent link to this record |
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| Author |
Granero, D.; Candela-Juan, C.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Jacob, D.; Mourtada, F. |
| Title |
Technical Note: Dosimetry of Leipzig and Valencia applicators without the plastic cap |
Type |
Journal Article |
| Year |
2016 |
Publication |
Medical Physics |
Abbreviated Journal |
Med. Phys. |
| Volume |
43 |
Issue |
5 |
Pages |
2087 - 4pp |
| Keywords |
Leipzig applicators; Valencia applicators; skin brachytherapy; Monte Carlo; dosimetry |
| Abstract |
Purpose: High dose rate (HDR) brachytherapy for treatment of small skin lesions using the Leipzig and Valencia applicators is a widely used technique. These applicators are equipped with an attachable plastic cap to be placed during fraction delivery to ensure electronic equilibrium and to prevent secondary electrons from reaching the skin surface. The purpose of this study is to report on the dosimetric impact of the cap being absent during HDR fraction delivery, which has not been explored previously in the literature. Methods: GEANT4 Monte Carlo simulations (version 10.0) have been performed for the Leipzig and Valencia applicators with and without the plastic cap. In order to validate the Monte Carlo simulations, experimental measurements using radiochromic films have been done. Results: Dose absorbed within 1 mm of the skin surface increases by a factor of 1500% for the Leipzig applicators and of 180% for the Valencia applicators. Deeper than 1 mm, the overdosage flattens up to a 10% increase. Conclusions: Differences of treating with or without the plastic cap are significant. Users must check always that the plastic cap is in place before any treatment in order to avoid overdosage of the skin. Prior to skin HDR fraction delivery, the timeout checklist should include verification of the cap placement. (C) 2016 American Association of Physicists in Medicine. |
| Address |
[Granero, D.] Hosp Gen Univ, Dept Radiat Phys, ERESA, Valencia 46014, Spain, Email: dgranero@eresa.com |
| Corporate Author |
|
Thesis |
|
| Publisher |
Amer Assoc Physicists Medicine Amer Inst Physics |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0094-2405 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000378924200010 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2753 |
| Permanent link to this record |
