radiation dosimetry, nuclear medicine, radiation therapy

Voximetry LLC

Personalized Dosimetry for RadioPharmaceutical Therapy

Software Solutions


Introducing Torch

Torch is a software tool designed to model drug activity and compute radiation dose, individualized for the drug, the radionuclide, and the patient.  Torch takes in patient scans (PET/CT or SPECT/CT) at several times points.  It then models the uptake and elimination of the drug, finding the best fit to describe its activity not only at the scan times, but throughout the duration of the drug's lifetime in the patient.  

Note: Torch is not yet 510(k) approved, and is therefore NOT suitable for clinical use.

Modular Design

Voximetry's world-class expertise is in pharmacokinetic modelling and dose computation.  Currently, Torch is designed to plug in to existing software that specializes in organ contouring and image registration.  Or use Torch as a standalone executable.  We let you decide.

Drug Modelling


Time Activity

Any drug injected into the blood stream will circulate through the body, being taken up by various organs and then eliminated from the body.  Meanwhile, the radionuclide continues to decay.  Torch helps you describe this process, which is crucial to providing an accurate estimate of the dose later on.

Advanced Curve Fitting

Torch automatically finds the curve type that best describes drug activity.  It also finds the parameters that best fit that curve.  You can tweak the parameters of your curve, or choose an entirely different one.

Dose Computation


Voxel-level Dosimetry

Until recently RPT dose calculations, if done at all, tended to compute dose on an organ level, ignoring all variations inside the organ.  Torch lets you compute dose at the voxel level, allowing you to see vastly more dose detail.

Kernel Dose Calculation

For super-fast dose calculation, try kernel convolution.  It takes pre-computed spreading functions and applies them to activity data.  The resulting distribution shows how much dose was deposited in each voxel of the patient.  Torch currently includes dose kernels for over a dozen radionuclides.

Monte Carlo Dose Calculation

Widely regarded as the most accurate method of dose calculation, Monte Carlo simulates individual particles as they transit the body.  By building up billions of these histories, Monte Carlo provides the gold standard in dose.  Torch permits full Monte Carlo calculations for photon-electron radionuclides, and partial Monte Carlo for alpha emitters.

Powered by GPU

All of Torch's dose calculations are powered by graphical processing units (GPUs).  These processors apply massive data-level parallelism to repetitive computation problems.  With GPU power, Torch lets you compute kernel dose in seconds or Monte Carlo dose in minutes.

Prescribe, Assess, Modify


Torch: Radiopharmaceutical Treatment Planning

External beam radiation therapy benefits from a wide range of planning tools that allow a high degree of confidence in the treatment before the patient is ever exposed to high doses of radiation.  Until now, the analogous tools for RPT planning have been lacking.  Torch provides a number of methods of analysis that will be instantly recognizable to anyone familiar with external beam planning, including dose clouds, organ-level dose statistics, and dose-volume histograms.

Pre-treatment Prescription

 Many RPT agents today are theranostic - depending on the isotope attached, they can be used for diagnostic imaging or for cancer therapy.  By injecting the diagnostic version, the path of the drug can be tracked through the patient, and the therapeutic behavior is then predicted.  The physician can then decide how much of the therapeutic agent to inject.  Torch lets you compare different drugs and radionuclides prior to treatment.

Treatment Assessment

Once treatment begins, the therapeutic activity can be imaged using SPECT.  Torch uses these images to compute dose and verify that the intended tumor dose is being delivered, and that organs at risk are not receiving toxic doses.  With this information, Torch allows physicians to modify the course of treatment - optionally adding or removing future cycles of drug injection.