Dose area product (DAP)

Dose Area Product (DAP), is a multiplication of the dose and the area exposed, often expressed in Gy.cm2.

Modern x-ray systems are fitted with a DAP meter, able to record accumulated DAP during an examination. A schematic of the imaging chain with DAP meter is given below.

How is DAP measured?
An ionization chamber larger than the area of the x-ray beam is placed just beyond the xray collimators. The DAP ionization chamber must intercept the entire x-ray field for an accurate reading. The DAP-value is depending on x-ray technique factors (kVp, mA, filtration) and time of the procedure and the area of the x-ray field.
For example, a 5 x 5 cm x-ray field with an entrance dose of 1 mGy will yield a 25 mGy.cm2 DAP value. If the field is increased to 10 x 10 cm, with the same entrance dose of 1 mGy the DAP increases to 100 mGy-cm2, which is 4 times the DAP for the 5 x 5 cm field.

Why DAP?
Dose-area product is relatively easy to measure. DAP has been shown to correlate well with the total energy imparted to the patient, which is related to the effective dose and therefore to overall cancer risk.
Estimated effective doses from DAP readings, are rough approximations. This is due to the fact that other factors are required for a more accurate estimate of effective dose or skin dose, such as the beam geometry with respect to the patient, kVp, and so on.
Despite these limitations, DAP is currently the most convenient method of monitoring patient doses.

DAP unit converter

With this converter, the dose area product (DAP) can be converted into corresponding values expressed by other units. Use other tool for DAP to effective dose (mSv) conversion. Note: use point in stead of comma as a decimal separator. DAP unit converter Type a value in the DAP field to convert to DAP in other units: DAP From mGy.cm2 cGy.cm2 dGy.cm2 Gy.cm2 uGy.m2 mGy.m2 Gy.m2 To mGy.cm2 cGy.cm2 dGy.cm2 Gy.cm2 uGy.m2 Gy.m2 Result DAP Simple example with respect to unit conversions: When converting from Gy.cm2 to µGy.m2 the following reasoning can be followed: 1 Gy = 1,000,000 (1 million) µGy; 1 cm2 = 0.0001 m2; this means that 1 Gy.cm2 = 1,000,000*0.0001 µGy.m2 = 100 µGy.m2. Note that some...

DAP to mSv converter - radiography

This tool calculates the effective dose (mSv) with respect to the DAP value (e.g. cGy.cm2) belonging to different types of radiograph . It does for instance, Gy.cm2 to mSv conversion. It is emphasized that the result is an estimation. The conversion factor relates to ICRP 103 and is obtained from: Radiation risks from medical x-ray examinations as a function of the age and sex of the patient, BF Wall et al., Report HPA-CRCE-028 (2011) ; www.hpa.org.uk Note: use point in stead of comma as a decimal separator. Input value dose area product (DAP) Gy.cm2 mGy.cm2 cGy.cm2 dGy.cm2 Gy.m2 ...

Website overview

Radiation dose converters DAP unit converter DAP to mSv converter DLP unit converter DLP to mSv converter (CT) Dose rate converter Dose unit converter Information on quantities and website Dose Area Product (DAP) Effective dose DAP in DICOM header Feedback form About dr Wizard Miscellaneous calculators Age calculator BMI calculator Background topics Image quality Learn more?

Radiation dose converters

Radiation dose converters DAP unit converter DAP to mSv converter DLP unit converter Effective dose calculator - DLP Dose rate converter

DLP unit converter

With this converter, the dose length product (DLP) can be converted into corresponding values expressed by other units. Note: use point in stead of comma as a decimal separator. Input value from mGy.cm cGy.cm dGy.cm Gy.cm uGy.m mGy.m cGy.m dGy.m Gy.m to mGy.cm cGy.cm dGy.cm Gy.cm uGy.m mGy.m cGy.m dGy.m Gy.m

Effective dose calculator - CTA-chest

This converter converts DLP in mSv effective dose. Note 1: use point in stead of comma as a decimal separator. Note 2: currently only for CTA-chest and a rough estimate. Input value (DLP) mGy.cm cGy.cm dGy.cm Gy.cm Gy.m Result Effective dose mSv

Dose rate converter

Dose rate is defined as: the quotient of the dose over a given period of time, and this duration. For example, the dose rate can be expressed in units of Gy/h. This converter helps to convert dose rate into another unit. Input value from uGy/s uGy/m uGy/h mGy/s mGy/m mGy/h cGy/s > to uGy/s uGy/m uGy/h mGy/s mGy/m mGy/h cGy/h > ...

DAP in DICOM header

DAP value in DICOM headers is given in dGy*cm*cm. It can be found at DICOM Tag (0018,115E). For more detail, see for instance this web page .

DLP to mSv converter

Here is a straightforward CT dose calculator for determining the Effective Dose (mSv) from the Dose Length Product (mGy cm) for a CT exam of a single organ. Type a value in the DLP field to convert to mSv effective dose: DLP DLP unit Gy.cm dGy.cm cGy.cm mGy.cm uGy.cm Patient 0 year old 1 year old 5 year old 10 year old adult Body region Head and Neck Head Neck Chest Abdomen and Pelvis Trunk k (mSv.mGy-1.cm-1) Effective dose (mSv) The values for the conversion factor that are used in the calculator are taken from the AAPM task group report on Radiation Dose Reporting .

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