PT  - JOURNAL ARTICLE
AU  - Yoriyaz, Hélio
AU  - Stabin, Michael G.
AU  - Santos, Adimir dos
TI  - Monte Carlo MCNP-4B–Based Absorbed Dose Distribution Estimates for Patient-Specific Dosimetry
DP  - 2001 Apr 01
TA  - Journal of Nuclear Medicine
PG  - 662--669
VI  - 42
IP  - 4
4099  - http://jnm.snmjournals.org/content/42/4/662.short
4100  - http://jnm.snmjournals.org/content/42/4/662.full
SO  - J Nucl Med2001 Apr 01; 42
AB  - This study was intended to verify the capability of the Monte Carlo MCNP-4B code to evaluate spatial dose distribution based on information gathered from CT or SPECT. Methods: A new three-dimensional (3D) dose calculation approach for internal emitter use in radioimmunotherapy (RIT) was developed using the Monte Carlo MCNP-4B code as the photon and electron transport engine. It was shown that the MCNP-4B computer code can be used with voxel-based anatomic and physiologic data to provide 3D dose distributions. Results: This study showed that the MCNP-4B code can be used to develop a treatment planning system that will provide such information in a time manner, if dose reporting is suitably optimized. If each organ is divided into small regions where the average energy deposition is calculated with a typical volume of 0.4 cm3, regional dose distributions can be provided with reasonable central processing unit times (on the order of 12–24 h on a 200-MHz personal computer or modest workstation). Further efforts to provide semiautomated region identification (segmentation) and improvement of marrow dose calculations are needed to supply a complete system for RIT. It is envisioned that all such efforts will continue to develop and that internal dose calculations may soon be brought to a similar level of accuracy, detail, and robustness as is commonly expected in external dose treatment planning. Conclusion: For this study we developed a code with a user-friendly interface that works on several nuclear medicine imaging platforms and provides timely patient-specific dose information to the physician and medical physicist. Future therapy with internal emitters should use a 3D dose calculation approach, which represents a significant advance over dose information provided by the standard geometric phantoms used for more than 20 y (which permit reporting of only average organ doses for certain standardized individuals)