NCIRF User Manual

Introduction

National Cancer Institute dosimetry system for Radiography and Fluoroscopy (NCIRF) is computer software to estimate organ and effective doses for patients undergoing diagnostic radiography and fluoroscopy, and fluoroscopically guided interventional procedures. The program is based on a comprehensive library of computational human phantoms (surrogate anatomy for patients) combined with a streamlined GEANT4 Monte Carlo radiation transport package.

Calculation steps

Patient characteristics

Two libraries of the computational human phantoms are implemented into NCIRF2.0: the reference size phantoms with arm-raised and arm-lowered. First, you need to select the arm-raised or arm-lowered postures. Next, You need to input the age and gender of a given patient whose organ dose is sought. Based on the input data, a phantom will be selected from the library of reference size pediatric and adult phantoms. You can select the patient’s age from five age groups: newborn, 1, 5, 10, 15 years old, and adult (generally assumed to be over 20 years). The best estimation needs to be used for in-between ages. For example, you may choose a 5 years old phantom for a 6-year-old patient. Once age is selected, the reference height and weight defined by the International Commission on Radiological Protection (ICRP) Publication 89 will be displayed at the bottom, which are not editable.

X-ray source definition

Next, you need to provide an x-ray source term. A series of x-ray energy spectra, combinations of the peak tube potential and half-value layer, can be selected from the dropdown menu. The user-defined x-ray spectrum cannot be entered in the current version. Other parameters such as source-to-isocenter distance (cm), field width at isocenter (cm), and field height at isocenter (cm) can be entered or adjusted using the up and down arrows. Changes in the size of the beam field will be automatically reflected on the phantom picture in the middle in the top, front, and lateral views. Source-to-origin distance will not be reflected in the phantom pictures. Lastly, physical measurement, Dose Area Product (Gy-cm2), needs to be entered to convert Monte Carlo-based organ dose (absorbed dose per particle launched) to absolute doses.

Beam geometry

You need to enter two angles, Positioner Primary Angle (PPA) and Positioner Secondary Angle (PSA), which are corresponding to azimuthal and polar angles, respectively, in a polar coordinate. The angles can be entered directly into the text boxes or adjusted using the up and down arrows. The changes in both angles will be automatically reflected in the phantom pictures in the top, front, and lateral views. You can also select a predefined beam direction from the dropdown menu. These two angles are following the definition by The National Electrical Manufacturers Association (NEMA) DICOM standard.

Monte Carlo dose calculations

From NCIRF version 2.0, multithreading calculation is supported. You can now specify the number of threads you would like to assign to the Monte Carlo simulations. The dropdown menu contains the number of threads from 1 to 18. The number of threads usually corresponds to the number of CPU cores in your computer. You may enter beyond the number of CPU cores but the performance may not improve. You also need to specify the number of Monte Carlo histories. You will need to adjust the history by checking the Monte Carlo statistical errors displayed next to the organ doses. When all parameters are defined, Monte Carlo calculations will be performed in the background when you press the button, “Calculate Organ Dose.” The input file will be generated in the background and processed by the GEANT4 module after combining with a phantom lattice file. While Monte Carlo calculation is running, the user interface may look frozen but once Monte Carlo calculations are completed, the interface will come back to normal.

Batch manager

You can utilize Batch Manager to run multiple input files. You can open Batch Manager by clicking the “Open Batch Manager” button or sending parameters directly by clicking the “Send setting to Batch” button, which will open Batch Manager automatically. The parameters defined in the user interface will be transferred to Batch Manager as shown below. The list of parameters in Batch Manager can be saved using the “Save Batch Set” button and Batch Manager can load an existing batch set file using the “Load Batch Set” button. When you double click each patient row, the setting will be reflected in the user interface. You can start Monte Carlo calculations using the “Run Batch Set” button and when the batch calculations are completed, a message “Batch calculation is completed” will pop up. Due to some technical difficulties, it is impossible to check the status of runs in the current version.

Dose output

Whenever Monte Carlo calculations are completed, the organ dose table on the right pane of the user interface will be refreshed with organ absorbed doses (mGy) with Monte Carlo errors (%) next to the organ doses. When any parameters are changed, the organ dose table will be erased for the next Monte Carlo runs. Effective dose (mSv) is calculated based on the tissue weighting factors defined by the ICRP Publication 103.

Features under development

• Create MCNP6 input files from Batch Manager
• Extend the phantom library to include body size-dependent phantoms
• Pregnant phantoms with fetal phantoms
• Custom x-ray spectrum

Version history

• 20221214 Official release version 2.0.20220418
• 20220418
  • Bug not reflecting custom angles fixed
• 20220317
  • Running on Windows virtual machine on Parallels
  • Error caused by the issues with the path to GEANT4 on non-English Windows fixed
• 20220307
  • Two phantom libraries with the arms raised and lowered are available
  • The initial phantom set to the newborn male phantom
  • Error fixed when no file is selected in “Load Batch Set” on Batch Manager
• 20211217
  • The Mac version with multithreading finally available!
  • Skeletal dose problem discovered in NCIRF1.0 multithread version solved
  • Multithread number can be specified with calculation time (min) displayed
  • No need to install under Documents folder (required for NCIRF1.0)
  • Arm-raised and arm-lowered phantoms available
• 20211206 Official release version 1.0.20211206
  • Support multithreading for Windows version
  • Bug reported: skeletal doses get zeros
• 20210926
  • Initialize the dose table created from the previous calculation when parameters change
  • Menus for User Manual and User Forum added under “Help” menu
• 20210901
  • Batch manager
  • Users can create a list of parameter sets (patient and technical parameters) by sending them from the GUI to Batch Manager.
  • Users can save/load the list of parameter sets.
  • Users can run the parameter sets in a batch mode
• 20210825
  • Bug not running history greater than 1E7 fixed
• 20210620 Official release version 1.0.20210620
• 20210115
  • NCIRF GEANT4 version completed
  • Critical bugs fixed: half field size, beam angle transformation
• 20200810
  • NCIRF MCNPX version completed
  • Test for Xojo interface to MCNPX input files completed