Please enable JavaScript.
Coggle requires JavaScript to display documents.
SURGICAL PLANNING - Coggle Diagram
SURGICAL PLANNING
General AIM:
to assess quantitavely different options as a function of the anatomo-pathological features of the patient
- measure distances, volumes and angles
- select instruments and implants
- select conspicuous points/landmarks
-
-
Examples of applications
-
- plane of femural head cut
-
- femural cavity preparation
- localization and removalof a deep-seated tumor
RADIOTHERAPY:
the plan is automatically transferred to the machine and the plan contains a lot of information also regarding the machine
--> high complexity
- physical modelling of the interaction between radiation beam and bilogical matter
(pencil beam), not only in one single moment, but in repeated daily fraction of the treatment
--> there is the need of very detailed information regarding the anatomical and pathological configuration of the patient
- the need of an accurate contouring of the target structures in this case is even more important
The contouring is associated to a set of numbers:
- how much I have to dose my target volume (from literature)
- dosage of the organs at risk (e.g. bladder/rectum) --> limited!
Optimization parameters to limit the dosage of organ at risks and to concentrate all the dosage on the target volume
- beam type and energy (X-ray/high energy beam/particle beam)
- number and dimension of fields
- if I consider only one beam, I will release too much dose along one single path
- if I use too much beams, I will have a too complicated geometry (increased time)
- static beam conformation (e.g. 4 static fields irradiation geometry)
- dynamic beam conformation
- collimator is the element that shapes the section of the beam
- machine rotates continously around the patient and while the machine is rotating the multi leaf collimator shape continously the radiation beam exiting from the machine in such a way that the section of the radiation beam complies with the section of the target
! The level of complexity of the treatment plan is so high in radiation oncology that there are treatment softwares that give back to the operator the values of the optimal geometrical parameters to have a certain geometry of dosage
There are models of interactions between the X-ray beam and the biological matter embedded in these treatment plan softwares
- the beam is modelled as a set of small beams (pencil beams)
- each of these rays is followed in its pathway through the body and it is modelled in terms of interactions and attenuation voxel by voxel
Dose-volume histogram
- assessment of the treatment plan in radiation oncology
- x-axis: percentage of the prescribed dose for a specific structure
- y-axis: percentage of the volume of that specific structure that receives that amount of dose
- the more square-shaped is the curve, the better is the dose deposition
PARTICLE BEAM THERAPY
- it is based on the use of high energy charged particles (protons and heavy ions) beams
- X-ray VS charged partcles:
- photons: dose delivered along the pathway
- protons/carbonb ions: no dose delivered along the pathway, all the energy is released at a certain depth and falls rapidly after the peak (Bragg peak)
- high geometrical selectivity
- higher biological effectiveness (carbon ions vs protons)
--> the damages produced on the DNA are primary and not repairable damages
- powerful weapon --> need to be even more accurate in delivering the beam
- ! inverse planning is a must
- video: beam deposes in each red spot (beam spots) a certain amount of particles and works layer by layer by changing the energy of the beam at the different depths
WHAT IS?
- definition of the geometrical parameters of the surgical procedure
- parameters needed for the surgical guidance (navigation) or to be provided to a robot
! there is no planning if there is no navigation/image guidance in the surgical room (and viceversa)
CAD paradigm
- establish parameters
- verify parameters in the PO phase
- freeze the set of parameters as the optimal set of parameters
- make them available in the surgical room as reference for what is going to happen and use them as guidance
! every surgical planner provides also the possibility to use quantitavely tools to assess the quality of the parameters that have been established
--> comparison of with the healthy side