DAVID Dose Delivery QA System

Real-Time Treatment Verification

with DAVID Detector

How it works


DAVID (Device for Advanced Verification of IMRT Deliveries)  is a transparent, multi-wire ionization chamber which is inserted into the LINAC accessory tray to verify and monitor dose delivery while the patient is treated. As it is placed between the MLC and the patient, it does not disturb the LINAC's light field.

The DAVID detector consists of measurement wires (the quantity depending on the MLC used) which run parallel to the direction of the MLC. Each measurement wire monitors the opening of a leaf pair. The measured dose length product thus correlates with the opening of the leaf pair and supplied dose. 

Before the first treatment is delivered, reference values are collected with the DAVID system, which are then compared online against the measurement obtained during each treatment fraction. Deviations from the initial plan, which are indicated by audible or visual alarms, are thus immediately detected.

Why verify dose at point of treatment?[1]

  • Equipment-related errors and deviations from the initial plan that may occur in the course of treatment can be detected.
  • Complexity of planning and delivery techniques increases risk for treatment-related incidents.
  • Of the more than 4,000 near misses without adverse outcome to patients reported in the years 1992 to 2007, more than 50% were related to the planning or treatment delivery stage.
  • Certain types of tumors require accuracy better (up to 3.5%) than 5% as recommended by ICRU Report 24 (1976).


Advantages of OCTAVIUS 4D with DAVID compared to conventional in vivo dosimetry

  • Complete solution for IMRT QA, including pre-treatment and dose delivery QA
  • Not limited to single point measurements
  • Wireless operation and data transfer (DAVID)
  • Real-time display of measurement results via Bluetooth (DAVID)
[1] Statistics from: Radiotherapy Risk Profile, WHO 2008
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DAVID Dose Delivery QA