[en] Daily, monthly, and annual quality control (QC) of linear accelerators are part of the major tasks of the medical physicist to verify that patients are receiving proper radiation treatment. The control tests consist of the measurement of beam output, verification of the beam energy, and determination of the beam flatness and symmetry in a linear accelerator. A new device, referred to as QC phantom, was designed and fabricated for the QC of linear accelerators. This device is accompanied by software generating the reports of all measured data, keeping track of day-to-day data, and plotting the results. The accuracy, reproducibility, and linearity of the QC phantom were evaluated in this project. Also, the user friendliness of this device for morning warmup of linear accelerators was tested

[en] The TG-43 recommended dosimetric characteristics of a new ¹²⁵I brachytherapy source have been experimentally and theoretically determined. The measurements were performed in Solid Water^TM using LiF TLDs. The calculations were performed using Monte Carlo simulations in Solid Water^Tm and water. The measured data were compared with calculated values as well as the reported data in literature for other source designs. The dose rate constant this source in water was 1.01±3% cGy h^-1 U^-1 and the anisotropy constant was 0.956

[en] 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 S_K Standard for ¹⁰³Pd. Measurements were performed in a Solid Water trade mark sign phantom using LiF thermoluminescent dosimeters. For these measurements, slabs of Solid Water trade mark sign phantom material were machined to accommodate the source and LiF TLD chips of dimensions (3.1x3.1x0.8 mm³) and (1.0x1.0x1.0 mm³). The TLD chips were surrounded by at least 10 cm of Solid Water trade mark sign phantom material to provide full scattering conditions. The Monte Carlo simulations were performed in Solid Water trade mark sign 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 trade mark sign . The Monte Carlo calculated dose rate constant of the Best registered 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 trade mark sign phantom material. Moreover, the radial dose function of the new source was calculated in liquid water and Solid Water trade mark sign at distances ranging from 0.1 to 7 cm using the PTRAN Monte Carlo Code. The anisotropy function, F(r,θ), of the new ¹⁰³Pd source was also measured in Solid Water trade mark sign and calculated in both Solid Water trade mark sign 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 registered ¹⁰³Pd source in Solid Water trade mark sign was 0.89±5%. Complete dosimetric data are described in this manuscript

[en] ¹²⁵I brachytherapy sources are being used for interstitial implants in tumor sites such as the prostate. Recently, the ADVANTAGE^TM125I, 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^TM phantom using LiF thermoluminescent dosimeters. The theoretical calculations were performed in both Solid Water^TM 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^TM and calculated both in water and Solid Water^TM at distances up to 10.0 cm. The anisotropy function, F(r,θ), of the new source was measured and calculated in Solid Water^TM 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^TM125I 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

[en] Recently an improved design of a ¹²⁵I brachytherapy source has been introduced for interstitial seed implants, particularly for prostate seed implants. This design improves the in situ ultrasound visualization of the source compared to the conventional seed. In this project, the TG-43 recommended dosimetric characteristics of the new brachytherapy source have been experimentally determined in Solid Water trade mark sign phantom material. The measured dosimetric characteristics of the new source have been compared with data reported in the literature for other source designs. The measured dose rate constant, Λ, in Solid Water was multiplied by 1.05 to extract the dose rate constant in water. The dose rate constant of the new source in water was found to be 0.99±8% cGy h^-1 U^-1. The radial dose function was measured at distances between 0.5 and 10 cm using LiF TLDs in Solid Water trade mark sign phantom. The anisotropy function, F(r,θ), was measured at distances of 2, 3, 5, and 7 cm

[en] Recently, several different models of ¹²⁵I and ¹⁰³Pd brachytherapy sources have been introduced in order to meet the increasing demand for prostate seed implants. These sources have different internal structures; hence, their TG-43 dosimetric parameters are not the same. In this study, the effects of the dosimetric differences among the sources on their clinical applications were evaluated. The quantitative and qualitative evaluations were performed by comparisons of dose distributions and dose volume histograms of prostate implants calculated for various designs of ¹²⁵I and ¹⁰³Pd sources. These comparisons were made for an identical implant scheme with the same number of seeds for each source. The results were compared with the Amersham model 6711 seed for ¹²⁵I and the Theragenics model 200 seed for ¹⁰³Pd using the same implant scheme.