PurposeIn this study, we attempted to obtain full dosimetric data for a new 90Y brachytherapy source developed by the College of Chemistry (Sichuan University) for use in high-dose-rate after-loading systems.Material and methodsThe dosimetric data for this new source were used as required by the dose calculation formalisms proposed by the AAPM Task Group 60 and Task Group 149. The active core length of the new 90Y source was increased to 4.7 mm compared to the value of 2.5 mm for the old 90Sr/90Y source. The Monte Carlo simulation toolkit Geant4 was used to calculate these parameters. The source was located in a 30-cm-radius theoretical sphere water phantom.ResultsThe dosimetric data included the reference absorbed dose rate, the radial dose function in the range of 1.0 to 8.0 mm in the longitudinal axis, and the anisotropy function with a θ in the range of 0° to 90° at 5° intervals and an r in the range of 1.0 to 8.0 mm in 0.2-mm intervals. The reference absorbed dose rate for the new 90Y source was determined to be equal to 1.6608 ± 0.0008 cGy s–1 mCi–1, compared to the values of 0.9063 ± 0.0005 cGy s–1 mCi–1 that were calculated for the old 90Sr/90Y source. A polynomial function was also obtained for the radial dose function by curve fitting.ConclusionsDosimetric data are provided for the new 90Y brachytherapy source. These data are meant to be used commercially in after-loading system.

Objective: Recently, a new catheter-based 32 P brachytherapy source has been developed (College of Chemistry, Sichuan University) for use in high-dose-rate afterloader. This study presents the results of the dosimetric data of the Geant4 Monte Carlo (MC) simulation toolkit for this new 32 P brachytherapy source. Methods: The new 32 P source had dimensions of 0.50-cm length and 0.08-cm diameter and was encapsulated in teflon. In this study, we attempted to obtain dosimetric data for this new source, as required by the formalism proposed by the American Association of Physicists in Medicine reports TG60 and TG149. The source was located in a 30-cm radius theoretical sphere water phantom, and the absorbed dose of the source was calculated using MC code. Results: The dosimetric data included the reference absorbed dose rate, the radial dose function in the range of 0.10-0.50 cm at a longitudinal axis, the polynomial function for the radial dose function and the anisotropy function with a u value of 0-90°in 5°intervals and an r of 0.10-0.35 cm in 0.01-cm intervals. The radial and axial dose profiles and away-along quality assurance table are also calculated for the unsheathed 32 P source. The dose rate D (r 0 ,u 0 ) at the reference point for the unsheathed 32 P source is determined to be equal to 1.2660 6 0.0006 cGy s 21 mCi. The radial dose function of the new 32 P source shows good agreement with the other 32 P source presented in this work with an average difference of 1.78%. Conclusion: Dosimetric data are provided for the new 32 P source. These data could be used in treatment-planning systems in clinical practice. Advances in knowledge: Provided a new beta-emitting brachytherapy source that is intended for treatment of liver cancer. A dosimetric study of the unsheathed 32 P source for which no published dosimetric data existed was performed. INTRODUCTIONAt present, more and more beta-emitting sources are utilized in brachytherapy fields, and many new types of brachytherapy sources are available. Two applications of beta-emitting brachytherapy sources have been proposed: (a) in intravascular brachytherapy-the dosimetric parameters of a 90 Sr/ 90 Y source were calculated by Holmes et al 1 using an experimental method. Soares et al 2 obtained a radial dose function and an anisotropy function from their measurements of an old 90 Sr/ 90 Y source in A150 plastic, and these authors also presented the Monte Carlo (MC) results of these dosimetric parameters. (b) In radiotherapy for localized tumours-the 32 P source model RIC-100 (developed by RI consultant) has been used for temporary radiation therapy of the spinal dura and other localized tumours, and dosimetric evaluations have been applied to the source with an MCNP5 (Monte Carlo