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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.



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.

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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. Input value   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 mGy.m2 Gy.m2 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 conversions won't result in any change, for example: 1 cGy*cm2 = 1 µGy*m2. DAP values can be translated into effective dose levels by multiplication using specific conversion factors. For this purpose it is important that DAP value and conversion factor match in terms of their units. The above DAP calcula

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

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

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

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Effective dose

Effective dose E is used as a measure of the radiation dose for expressing relative risk to humans. The exposures related to different types of medical x-ray examinations can be compared using the quantity effective dose. Why effective dose? The effective dose E, often expressed in millisievert (mSv), is generally used as a measure of radiation dose of patients and personnel in medical diagnostics . Unless indicated otherwise, 'dose' often refers to effective dose. Using  the quantity effective dose, the exposures for different types of medical x-ray examinations can be compared. The effective dose is not a measurable quantity, but is calculated from the physically absorbed dose (with Gray (Gy) as a unit) in the exposed tissues/organs. The point is that different tissues/organs are not equally sensitive to the possible adverse effects of radiation, such as cancer induction and mutations. For this reason, the different tissues/organs have been assigned tissue weighting fa

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 >                                     ...or use SHARE button f