Monte carlo dose calculation in dental amalgam phantom
Mohd Zahri Abdul Aziz1, AL Yusoff2, ND Osman3, R Abdullah4, NA Rabaie1, MS Salikin5
1 Oncological and Radiological Science Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas 13200, Penang, Malaysia
2 Department of Nuclear Medicine, Radiotherapy, and Oncology, School of Medical Science, Universiti Sains Malaysia, Penang, Malaysia
3 Oncological and Radiological Science Cluster, Advance Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas 13200, Penang; Medical Radiation Program, School of Health Science, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
4 Medical Radiation Program, School of Health Science, Universiti Sains , 16150 Kubang Kerian, Kelantan, Malaysia
5 Department of Medical Imaging, Faculty of Health Science, Universiti Teknologi MARA, 42300 Puncak Alam, Selangor, Malaysia
Mohd Zahri Abdul Aziz
Oncological and Radiological Science Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Bertam, 13200 Kepala, Batas Penang
Source of Support: Nil., Conflict of Interest: There are no conflicts of interest.
It has become a great challenge in the modern radiation treatment to ensure the accuracy of treatment delivery in electron beam therapy. Tissue inhomogeneity has become one of the factors for accurate dose calculation, and this requires complex algorithm calculation like Monte Carlo (MC). On the other hand, computed tomography (CT) images used in treatment planning system need to be trustful as they are the input in radiotherapy treatment. However, with the presence of metal amalgam in treatment volume, the CT images input showed prominent streak artefact, thus, contributed sources of error. Hence, metal amalgam phantom often creates streak artifacts, which cause an error in the dose calculation. Thus, a streak artifact reduction technique was applied to correct the images, and as a result, better images were observed in terms of structure delineation and density assigning. Furthermore, the amalgam density data were corrected to provide amalgam voxel with accurate density value. As for the errors of dose uncertainties due to metal amalgam, they were reduced from 46% to as low as 2% at d80 (depth of the 80% dose beyond Zmax) using the presented strategies. Considering the number of vital and radiosensitive organs in the head and the neck regions, this correction strategy is suggested in reducing calculation uncertainties through MC calculation.