MU Calculations
A special case of TPR when normalizing to dmax.
What is TMR?
These can be motorized, physical, or dynamic.
What are wedges?
What is water?
This inhomogeneity correction method, also known as the power-law method, is surprisingly accurate and can be easily done with hand calculations.
What is the Batho / power law correction method?
This non-lead material is used to shield photons and electrons, and has a low melting point.
What is cerrobend?
If you want to convert TMR to PDDs, you need to perform an inverse square correction and take the ratio of this specific correction factor at two field sizes.
What are the phantom scatter factors (Sp)?
This is the optimal wedge angle for 2 beams at different gantry angles.
What is the 'hinge' angle, or
wedge angle = 90o - (hinge angle)/2
These are often used for patient positioning, establishing a reference coordinate system on the patient outside the CT scanner, and facilitate the placement of patient marks, such as tattoos.
What are laser positioning systems?
This type of dose calculation simulates the transport, scatter, and energy deposition of particles with computers.
What is a Monte Carlo dose calculation?
This is the first F in an FFF beam.
What is flattening?
TG-74, recommends the measurement of Sc directly by constructing and placing one of these over your ion chamber.
What is a miniphantom?
It is the ICRU volume that consists of demonstrated tumor(s) if present and any other tissue with presumed tumor. There are no tumor cells outside this volume.
What is the Clinical Target Volume, or CTV?
The couch tops of most modern CT scanners are made from this lightweight and rigid material.
What is carbon fiber?
These are discretized regions of interest where dose is computed, which rhymes with voxel.
What is the dose voxel, or doxel, size?
The thin part of a wedge: or the place you wouldn't want to drop it on.
What is the toe?
Physical wedge factors depend on field size, off-axis distance, energy, and this.
What is depth?
It is the additional internal margin added to the CTV that compensates for physiological movements and variations in size, shape and position during treatment.
What is the Internal Target Volume, or ITV?
This human/animal organ has a tissue density that ranges from 0.1 to 0.4 g/cm3.
What is lung tissue?
These three dimensional objects can be placed above the patient to account for patient surface variations, and no, we're not talking about bolus.
What are compensators?
A popular publicly available Monte Carlo code package, or a food commonly used for breakfast.
What is EGS(4/5/nrc)?
For Cobalt-60 teletherapy calculations, this is the correction factor owing to the fact that the source needs to be moved from the shielding assembly to the treatment head.
What is the shutter correction factor?
It should be selected so that it is clinically relevant and representative of the PTV;easily defined and unambiguous; and should not be in the penumbra.
What is the ICRU Reference Point?
High density materials, such as hip prosthetics, metal dental fillings, and pacemakers can result in these (not prehistoric) objects on the reconstructed CT images.
What are CT artifacts?
This transport equation must be solved if you choose to calculate the dose analytically
What is the Boltzmann transport equation?
Cunningham!