[Three-dimensional dose calculation of 153Sm-EDTMP in treating bone metastasis--comparison of Monte Carlo and S value calculation methods].

Abstract

BACKGROUND & OBJECTIVE:

Three-dimensional (3D) dose calculation of radionuclide therapy for specified patients is a research interest in nuclear medicine, of which the main methods include S value calculation method, dose point kernel calculation method, and Monte Carlo (MC) simulation method. This study was to compare 3D absorbed dose calculation of 153Sm-EDTMP in treating a specified patient with bone metastasis between MC and S value methods.

METHODS:

A 3D dose calculation program was built based on the MC program EGS4, and the S value of nuclide 153Sm was calculated. For the specified patient with bone metastasis, 153Sm activity in excreted urine was measured at 0, 0.5, 2, 3.5, 5 and 6 h after injection of 153Sm-EDTMP. The accumulative activity is calculated by fitting measurement data. Based on the fusion SPECT/CT images of the patient, 3D absorbed dose is calculated by MC and S value methods.

RESULTS:

The iso-dose distribution curves of MC and S value calculation results were similar, and the dose was mainly collected in the bone. According to the 2 methods, the maximum doses were 3.92 Gy and 3.71 Gy with a difference of 5%. On the dose-volume histogram of the calculation volume, D10 (the highest dose of the 10% volume) were 2.14 Gy and 2.00 Gy with a difference of 7%; D20 (the highest dose of the 20% volume) were 0.58 Gy and 0.51 Gy with a difference of 14%. In general, the data of S value calculation were smaller than the data of MC calculation.

CONCLUSIONS:

MC and S value could be used to calculate the 3D dose of radionuclide therapy based on nuclear medical image. S value is a fast and simple method for the dose evaluation although the error of the calculation is relatively bigger.

• Authors: Li-Xin Chen, Xiao-Wei Liu, Feng Gan, Qiang Tang, Ri-An You, Wei-Guang Zhang, Wei Fan
• Journal: Ai zheng = Aizheng = Chinese journal of cancer (Ai Zheng) Vol. 25 Issue 11 Pg. 1399-405 (Nov 2006) China
• PMID: 17094909 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Organometallic Compounds
• Organophosphorus Compounds
• Radioisotopes
• Samarium
• samarium Sm-153 lexidronam

Topics

• Bone Neoplasms (radiotherapy, secondary)
• Humans
• Imaging, Three-Dimensional (methods)
• Monte Carlo Method
• Organometallic Compounds (therapeutic use)
• Organophosphorus Compounds (therapeutic use)
• Radioisotopes (therapeutic use)
• Radiotherapy Dosage
• Samarium (therapeutic use)
• Tomography, Emission-Computed, Single-Photon (methods)
• Tomography, X-Ray Computed (methods)