Portal de Periódicos da CAPES

Study of encapsulated T170m sources for their potential use in brachytherapy

2010; Wiley; Volume: 37; Issue: 4 Linguagem: Inglês

10.1118/1.3360441

2473-4209

Facundo Ballester, Domingo Granero, José Pérez‐Calatayud, Jack Venselaar, Mark J. Rivard,

Radiation Therapy and Dosimetry

Medical PhysicsVolume 37, Issue 4 p. 1629-1637 Radiation therapy physics Study of encapsulated sources for their potential use in brachytherapy Facundo Ballester, Facundo Ballester Department of Atomic, Molecular and Nuclear Physics, University of Valencia, E-46100 Burjassot, Spain and IFIC, CSIC, University of Valencia, E-46100 Burjassot, Spain Author to whom correspondence should be addressed. Electronic mail: [email protected]; Telephone: +34963544216; Fax: +34963544581.Search for more papers by this authorDomingo Granero, Domingo Granero Department of Radiation Oncology, ERESA, Hospital General Universitario, E-46014 Valencia, SpainSearch for more papers by this authorJose Perez-Calatayud, Jose Perez-Calatayud Department of Radiation Oncology, La Fe University Hospital, E-46009 Valencia, SpainSearch for more papers by this authorJack L. M. Venselaar, Jack L. M. Venselaar Department of Medical Physics, Instituut Verbeeten, Tilburg 5000LA, The NetherlandsSearch for more papers by this authorMark J. Rivard, Mark J. Rivard Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111Search for more papers by this author Facundo Ballester, Facundo Ballester Department of Atomic, Molecular and Nuclear Physics, University of Valencia, E-46100 Burjassot, Spain and IFIC, CSIC, University of Valencia, E-46100 Burjassot, Spain Author to whom correspondence should be addressed. Electronic mail: [email protected]; Telephone: +34963544216; Fax: +34963544581.Search for more papers by this authorDomingo Granero, Domingo Granero Department of Radiation Oncology, ERESA, Hospital General Universitario, E-46014 Valencia, SpainSearch for more papers by this authorJose Perez-Calatayud, Jose Perez-Calatayud Department of Radiation Oncology, La Fe University Hospital, E-46009 Valencia, SpainSearch for more papers by this authorJack L. M. Venselaar, Jack L. M. Venselaar Department of Medical Physics, Instituut Verbeeten, Tilburg 5000LA, The NetherlandsSearch for more papers by this authorMark J. Rivard, Mark J. Rivard Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111Search for more papers by this author First published: 18 March 2010 https://doi.org/10.1118/1.3360441Citations: 21 0094-2405/2010/37(4)/1629/9/$30.00 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Abstract Purpose: High dose-rate (HDR) brachytherapy is currently performed with sources, and has returned recently into clinical use as a source for this kind of cancer treatment. Both radionuclides have mean photon energies high enough to require specific shielded treatment rooms. In recent years, has been explored as an alternative for HDR-brachytherapy implants. Although it has mean photon energy lower than , it still requires extensive shielding to deliver treatment. An alternative radionuclide for brachytherapy is because it has three physical properties adequate for clinical practice: (a) 128.6 day half-life, (b) high specific activity, and (c) mean photon energy of 66.39 keV. The main drawback of this radionuclide is the low photon yield (six photons per 100 electrons emitted). The purpose of this work is to study the dosimetric characteristics of this radionuclide for potential use in HDR-brachytherapy. Methods: The authors have assumed a theoretical cylindrical source encapsulated with stainless steel and typical dimensions taken from the currently available HDR brachytherapy sources. The dose-rate distribution was calculated for this source using the GEANT4 Monte Carlo (MC) code considering both photon and electron spectra. The AAPM TG-43 U1 brachytherapy dosimetry parameters were derived. To study general properties of 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 source were compared to those for and 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 of the cylindrical source was . The behavior of the radial dose function showed promise for applications in brachytherapy. Due to the electron spectrum, the anisotropy was large for . Variations in manufacturing tolerances did not significantly influence the final dosimetry data when expressed in . For typical capsule dimensions, maximum reference dose rates of about 0.2, 10, and would then be obtained for , , and , respectively, resulting in treatment times greater than those for HDR brachytherapy. Conclusions: The dosimetric characteristics of source designs exploiting the low photon energy of were studied for potential application in HDR-brachytherapy. Dose-rate distributions were obtained for cylindrical and simplified spherical source designs (stainless steel and platinum capsule materials) using MC calculations. Despite the high activity of , calculated treatment times were much longer than for . Citing Literature Volume37, Issue4April 2010Pages 1629-1637 RelatedInformation