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Cocoon Training Manual
MaxRay Safety
Exposure Time
There is only one variable of exposure on the Cocoon unit that can be changed for a given radio-
graph … exposure time. The Cocoon has exposure factors of mA and kV that are fixed and cannot be
changed by the operator. The exposure time is changed based on patient age (adult or child), image
receptor (film or digital), and the location of teeth being imaged. The operator makes selections of
age, receptor, and position on the Cocoon, and in turn the Cocoon provides a suggested range of ex-
posure time in increments of 0.05 seconds. For example, a selection of adult, digital (sensor), molar
results in suggested time option of 0.40 seconds (see chart below). See the User’s Manual for more
details on selecting the exposure time.
There is a direct correlation between exposure time and dose. If exposure time is increased, patient
dose increases. There is certainly a trade-o between image quality and patient dose. It is important
to practice ALARA by keeping dose as low as possible while maintaining adequate image quality for
diagnosis. Exposure to the operator and the patient should be limited and having to repeat images
should be avoided.
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