Updating the Planar Patterson- Parker Table for Ir-192 and Cs-137 Brachytherapy Sources Using the Most Recent TG-43U1 Recommended Dosimetric Parameters
Journal Title: Journal of Biomedical Physics and Engineering - Year 2012, Vol 2, Issue 1
Abstract
Background: The Patterson-Parker table was created in 1934 to determine mg-hr required to deliver the prescribed dose to the treatment area. These tables were created using the dosimetric data for 226Ra that was determined in air and were utilized for dose calculations around implants with Ra-equivalent radionuclides such as 137Cs and 192Ir. Therefore, the differences of the tissue attenuation and anisotropy of these radionuclides and their impact on dose uniformity of the implants were ignored. Objective: In this study, the Patterson-Parker table has been updated for 137Cs and 192Ir sources using their recent dosimetric data. Furthermore, the dose uniformity for different loading schemes, as a function of the implant area, was tested. Methods: The updated Paterson-Parker tables were generated for 137Cs and 192Ir sources using their published dosimetric parameters that have been determined following the American Association of Physicists in Medicine (AAPM) Task group 43 (TG-43U1) recommendations. The accuracies of the updated tables were examined by two independent methods, Monte Carlo simulation technique and a commercially available treatment planning system. In addition to the dose values along the central axis of the implant, dose profiles along two orthogonal directions were evaluated for the selection of the optimal radioactivity distribution in an implant. Results: We found that the original Paterson-Parker loading scheme of the radioactivity as a function of the implant size has to be adjusted to achieve the optimal dose distribution (1000 cGy ±10%) in an implant. In addition, it was shown that the same implant size for the mg-hr required for 137Cs was not identical to that of 192Ir. Similarly, there were some differences between the updated table and the published Paterson-Parkers tables. Independent Monte Carlo simulations and treatment planning data had excellent agreement with the updated data. Conclusion: The conventional version of Paterson-Parker tables are not useful for the two commonly used brachytherapy sources. The updated version of the tables should be used instead.
Authors and Affiliations
Z. Naghshnezhad, R. Faghihi, M. A. Mosleh-Shirazi, A. S. Meigooni
Keywords
Related Articles
- EP ID EP86712
- DOI -
- Views 146
- Downloads 0
Comparison and Evaluation of Different Treatment Plans with IFRT Field and 6 and 18 MV Energies in Hodgkin’s Lymphoma Involvement Neck and Mediastinum
Background: Radiotherapy with large mantle field is an effective technique in increasing the risk of secondary cancers among HL (Hodgkin Lymphoma) patients; therefore, it is essential to choose an effective treatment fie...
In vitro Evaluation of the Relationship between Gray Scales in Digital Intraoral Radiographs and Hounsfield Units in CT Scans
Background: Jaw bone quality plays an essential role in treatment planning and prognosis of dental implants. Regarding several available methods for bone density measurements, they are not routinely used before implant s...
Simulation study of Hemodynamic in Bifurcations for Cerebral Arteriovenous Malformation using Electrical Analogy
Background and Objective: Cerebral Arteriovenous Malformation (CAVM) hemodynamic is disease condition, results changes in the flow and pressure level in cerebral blood vessels. Measuring flow and pressure without cathete...
A New Potential Contrast Agent for Magnetic Resonance Imaging: Iron Oxide-4A Nanocomposite
Background: Magnetic resonance imaging (MRI) contrast agents have an important role to differentiate healthy and diseased tissues. Access and design new contrast agents for the optimal use of MRI are necessary. This stud...
Can Evolutionary-based Brain Map Be Used as a Complementary Diagnostic Tool with fMRI, CT and PET for Schizophrenic Patients?
Objective: In this research, a new approach termed “evolutionary-based brain map” is presented as a diagnostic tool to classify schizophrenic and control subjects by distinguishing their electroencephalogram (EEG) featur...