103Pd and 125I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, a double-wall 103Pd source has been introduced, which has a design different from that of sources presently on the market. Dosimetric characteristics (dose rate constant, radial dose function, and anisotropy function) of this source were experimentally and theoretically determined following the AAPM Task Group 43 recommendations and were related to the October 10, 2000 revision of the NIST 1999 SK Standard for 103Pd. Measurements were performed in a Solid Water phantom using LiF thermoluminescent dosimeters. For these measurements, slabs of Solid Water phantom material were machined to accommodate the source and LiF TLD chips of dimensions (3.1 x 3.1 x 0.8 mm3) and (1.0 x 1.0 x 1.0 mm3). The TLD chips were surrounded by at least 10 cm of Solid Water phantom material to provide full scattering conditions. The Monte Carlo simulations were performed in Solid Water and liquid water using the PTRAN code. The results of this investigation show an excellent agreement (within 5%) between the measured (0.67+/-8% cGy h(-1) U(-1)) and calculated (to be 0.65+/-3% cGy h(-1) U(-1)) dose rate constant in Solid Water. The Monte Carlo calculated dose rate constant of the Best 103Pd in water was found to be 0.67+/-0.02 cGy h(-1) U(-1). The radial dose function, g(r), of the new 103Pd source was measured at distances ranging from 0.5 and 7 cm using LiF TLD in Solid Water phantom material. Moreover, the radial dose function of the new source was calculated in liquid water and Solid Water at distances ranging from 0.1 to 7 cm using the PTRAN Monte Carlo Code. The anisotropy function, F(r, theta), of the new 103Pd source was also measured in Solid Water and calculated in both Solid Water and water phantom material. From the anisotropy functions, the anisotropy factors, and anisotropy constant were calculated for each medium. The results indicated that the measured anisotropy constant of the Best 103Pd source in Solid Water was 0.89+/-5%. Complete dosimetric data are described in this manuscript.

125I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, the ADVANTAGE 125I, Model IAI-125, source became commercially available for interstitial brachytherapy treatment. Dosimetric characteristics (dose rate constant, radial dose function, and anisotropy function) of this source were experimentally and theoretically determined, following the AAPM Task Group 43 recommendations. Derivation of the dose rate constant was based on recent NIST WAFAC calibration performed in accordance with their 1999 standard. Measurements were performed in Solid Water phantom using LiF thermoluminescent dosimeters. The theoretical calculations were performed in both Solid Water and water using the PTRAN Monte Carlo code. The results indicated that a dose rate constant of the new source in water was 0.98 +/- 0.03 cGy h(-1) U(-1). The radial dose function of the new source was measured in Solid Water and calculated both in water and Solid Water at distances up to 10.0 cm. The anisotropy function, F(r, theta), of the new source was measured and calculated in Solid Water at distances of 2 cm, 3 cm, 5 cm, and 7 cm and also was calculated in water at distances ranging from 1 cm to 7 cm from the source. From the anisotropy function, the anisotropy factors and anisotropy constant were derived. The anisotropy constant of the ADVANTAGE 125I source in water was found to be 0.97 +/- 0.03. The dosimetric characteristics of this new source compared favorably with those from the Amersham Health Model 6711 source. Complete dosimetric parameters of the new source are presented in this paper.

125I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, the Best 125I source became commercially available for interstitial brachytherapy treatment. Dosimetric characteristics (dose rate constant, radial dose function, and anisotropy function) of this source were experimentally determined, following the AAPM Task Group 43 recommendations, and were related to the NIST 1999 calibration assigned to this source. Measurements were performed in Solid Water phantom using LiF thermoluminescent dosimeters. The results indicated a dose rate constant, lambda, of 1.01 +/- 0.08 cGy h(-1) U(-1) for the new source. The radial dose function, g(r), of the new source was measured at distances ranging from 0.5 to 10.0 cm. The anisotropy function, F(r, theta), of the new source was measured at distances of 2, 5, and 7 cm from the source center. These data compare favorably with those from the Nycomed/Amersham Models 6711 and 6702 sources. The anisotropy constant, phi(an), of the Best 125I source was found to be 0.982. Complete dosimetric parameters of the new source are presented in this paper.

For roughly 25 years, normalI125 and Pd103 sources have been used in the treatment of various malignant diseases such as prostate cancer. Various new sources have been marketed and produced to meet the demand for new sources to use in treatment. Recently, IsoAID LLC created the ADVANTAGE Pd103 source. Various dosimetric parameters must be determined to facilitate treatment planning using this source. Theoretical determination of dosimetric characteristics, dose rate constant, radial dose function, and anisotropy function for this new source followed the American Association of Physicists in Medicine (AAPM) Task Group 43U1 recommendations. Theoretical calculations were performed in liquid water using the PTRAN Monte Carlo code version 7.44. The radial dose function of the new source was calculated in liquid water at distances up to 10.0 cm, and the anisotropy function, at distances ranging from 0.5 cm to 7.0 cm. The anisotropy factors and anisotropy constant were derived from the anisotropy function. The results in water indicate that the dose rate constant is 0.709±0.014 cGy•normalh−1•normalU−1 and that the anisotropy constant is 0.880±0.040. The dosimetric characteristics of this new source compare favorably with those of other commercially available Pd103 sources.PACS: 87.53.Jw

125I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, a new 125I source has been introduced, which has a design different from that of other sources presently on the market. Dosimetric characteristics of this source, including dose rate constant, radial dose function, and anisotropy function, were determined experimentally following the AAPM Task Group 43 recommendations. The characteristics were related to the 1999 NIST calibration assigned to this source [SK,99std]. Measurements were performed in a solid water phantom using LiF thermoluminescent dosimeters. For these measurements, slabs of solid water phantom material were machined to accommodate the source and LiF TLD chips of dimensions (3.1 x 3.1 x 0.8 mm3) and (1.0 x 1.0 x 1.0 mm3). The TLD chips were surrounded by at least 10 cm of solid water phantom material to provide full scattering conditions. The results indicated a dose rate constant, lambda, of 0.88 +/- 0.07cGyh(-1)U(-1) for the new 1251 source as compared to 0.98 and 1.04 cGy h(-1)U(-1) for the Nycomed/Amersham model 6711 and 6702 seeds, respectively. Per TG-43, the values reported here represent the dose absorbed by water at 1 cm from the source in a water medium. The radial dose function, g(r), of the new 125I source was measured at distances ranging from 0.5 to 10 cm. The anisotropy function, F(r,theta), of the new 125I source was measured at distances of 2 and 5 cm from the source center. Calculations of anisotropy and radial dose function were also made using a Monte Carlo code. These calculations were made for both solid water and liquid water, the former to validate the Monte Carlo code and the latter to provide results in liquid water for clinical use. All data compared favorably with those from the Nycomed/Amersham models 6711 and 6702 sources.