EqualClinic I Pharma Solutions I QA Package I Center Validation I Patient Validation I Data Collection
  Patient Validation  
  • Each patient’s treatment plan is uploaded to our database by the center before the treatment begins.
  • EqualEstro’s international panel of experts and opinion leaders in the field review the complete set of data filtering out protocol deviations.
  • The center is then able to make the necessary modifications in time.
  • Each treatment is also reviewed after it is completed to make sure that it was delivered according to protocol.
The first step towards a successful treatment is the setting up of the patient on the treatment table in a firm and reproducible way and making a CT scan in this position. Each center has its own kind of fixation system ranging from modern, easy-to-use equipment ensuring high precision to local products that have not gone through a validated testing procedure. The imaging equipment available at centers differs and this also affects the quality of the treatment planning. How do we know that the center can provide fixation and imaging with the required precision?

When reviewing a patient case for the first time, the center is asked to describe and provide pictures of the fixation system and to send us the planning CT scan images. They also provide us with the original diagnostic images for comparison and all other diagnostic information available. In this way we make sure that treatment is adequate for the diagnosis and that the patient is positioned in a way to allow sufficient accuracy in planning and treatment delivery.
The greatest diversity in radiation therapy is found in the contouring or delineation of the target volumes on the planning CT. Each center has its own traditions and practices on how to interpret the diagnostic information, how to apply large margins, how much radiation they accept in surrounding tissue and so on. How do we know if the patients are getting the same kind of treatment at the different centers and that the patient is not put at risk by variations in target definition?

One of the most important parts of the initial patient case review is the checking of the delineation. The target must be defined according to protocol and the surrounding organs at risk must be accurately delineated. The addition of margins must follow protocol specifications in order for the different treatments to be comparable. The protocol should define clearly the prescribed doses and the maximum dose allowed to the organs at risk in order to make the treatments homogenous and to avoid additional adverse events.
The center’s physicist and radiation oncologist are responsible for producing a suitable plan for irradiating the patient. They use the treatment planning system (TPS) to design this plan entering parameters such as beam energies, field arrangement and field shapes. The TPS then calculates the doses delivered to each point of the patient using this plan. The calculation algorithms used for this differ from one TPS to the next and so does the accuracy of the calculations.

How do we verify that the plan and the calculated doses are comparable and compliant with the protocol? When the TPS has calculated the doses planned to the different volumes, it presents these on the planning CT itself or in graphs called dose-volume histograms. The reviewers use these to check the target dose and dose variability within the target volume. The reviewers also check if the dose to the organs at risk is below what is allowed. The review process also checks the adequacy of field arrangement and the beam energies used. The TPS’s dose calculations can be checked by EqualEstro’s independent dose verification program, EqualDose. This ensures comparable doses whatever planning system is used.

Once the plan has been accepted it needs to be executed with equal precision. The patient’s position on the planning images has to be reproduced every time and the patient needs to be kept in that position through-out the treatment. The treatment unit has to be well calibrated and programmed to deliver the planned doses. The treatments have to be given within the planned timeframe in order to have comparable effect. How do we make sure that these requirements are met?

Before the treatment can start a simulation session is done to make sure that the plan is applicable to the patient. Patient positioning is then verified with x-ray or CT images several times during the treatment to avoid systematic errors. The center provides these images to the reviewers as proof that accurately planned doses are accurately delivered to the volumes that were intended. It is also important that the center documents the treatment with treatment charts. The timelines and the delivery can be checked in this way and patients with major deviations in these aspects, who are at risk for a worse prognosis, can be identified.