en Radiation Biology Radiation Biology تحقيق بديع Original Research <span style="font-weight: bold">Background:</span> In nuclear medicine application often it is required to use computational methods for evaluation of organ absorbed dose. Monte Carlo simulation and phantoms have been used in many works before. The shape, size and volume in organs are varied, and this variation will produce error in dose calculation if no correction is applied. <span style="font-weight: bold">Materials and Methods:</span> A computational framework for constructing individual phantom for dosimetry was performed on five liver CT scan data sets of Japanese normal individuals. The Zubal phantom was used as an original phantom to be adjusted by each individual data set. This registration was done by Spherical Harmonics (SH) and Thin-Plate Spline methods. Hausdorff distance was calculated for each case. <span style="font-weight: bold">Results:</span> Result of Hausdorff distance for five individual phantoms showed that before registration ranged from 140.9 to 192.1, and after registration it changed to 52.5 to 76.7. This was caused by index similarity ranged from %56.4 to %70.3. <span style="font-weight: bold">Conclusion:</span> A new and automatic three-dimensional (3D) phantom construction approach was suggested for individual internal dosimetry simulation via Spherical Harmonics (SH) and Thin-Plate Spline methods. The results showed that the individual comparable phantom can be calculated with acceptable accuracy using geometric registration. This method could be used for race-specific statistical phantom modeling with major application in nuclear medicine for absorbed dose calculation. Iran. J. Radiat. Res., 2010 7 (4): 201-206 Dosimetry, individual phantom, thin-plate spline, Monte Carlo simulation, spherical harmonics. 201 206 http://ijrr.com/browse.php?a_code=A-10-1-337&slc_lang=en&sid=1 F. Babapour Mofrad farshid.mofrad@yahoo.com 790031947532846001806 790031947532846001806 Yes R. Aghaeizadeh Zoroofi 790031947532846001904 790031947532846001904 No A. Abbaspour Tehrani Fard 790031947532846001905 790031947532846001905 No Sh. Akhlaghpoor 790031947532846001906 790031947532846001906 No Y.W. Chen 790031947532846001907 790031947532846001907 No Y. Sato 790031947532846001908 790031947532846001908 No