Model DAP -Dose Area Product Measuring System

A DAP meter measures the incident air kerma area product (DAP) at the position of the patient. According to specific national guidelines, the recording of the DAP value is required for comparison with diagnostic reference levels in radiology and fluoroscopy.

VacuTec provides a wide range of rectangular light transparent DAP chambers suitable for most of the X-ray systems on the market. Circular DAP chambers, customized for use in different C-arm machines are also available.

The rectangular light transparent DAP meters are slid into the accessory rails at light field collimators, whereas in C-arm machines the DAP chamber is usually installed inside the housing of the X-ray source. DAP meters can be used as stand alone systems, e.g. for the retrofitting of existing X-ray machines. The wireless configuration, using an independent battery power supply and an integrated display unit, or alternatively, a wireless data transfer to an external display unit makes installation very easy. Wired configurations are also possible.

Most modern X-ray systems are equipped with a built in DAP-meter. In this case the measured values are directly linked to the digital X-ray image.

The standard VacuDAP factory calibration is done at 70 kV with a tube filtration of 2.5 mm Al and without additional absorbers.

The DAP/air kerma meter measures incident air kerma at the reference point in addition to the DAP. The recording and display of air kerma at the reference point is required for interventional and fluoroscopy procedures (IEC 60601-2-54, IEC 60601-2-43, CFR 1020.32).

Since the air kerma is dependent on the distance from the focus, it is important to clearly define the position of the measurement chamber and the reference point. Both distances affect the measuring values and must be transferred and updated to the air kerma meter.

Nearly all models of VacuDAP are available as VacuDAP duo versions. The design and mechanics are equivalent to VacuDAP. The installation options are as described for the VacuDAP systems.

Technically the VacuDAP duo measuring chambers contain a second, invisible, central sensor with a measuring channel for the air kerma and a second channel for DAP measurement.

Factory calibration of the DAP channel is done in accordance with VacuDAP. The factory calibration of the air kerma channel is done with default values for the distance of focus to chamber and the distance of focus to reference point. These default values have to be adjusted to the true values for each installation.

The calibration should be checked after installation.