field-in-field
Also written as: FiF — Field-in-Field
A technique using subfields within the primary treatment field to improve dose homogeneity.
Full Definition
Field-in-field (FiF) is a forward-planned technique that uses multiple subfields with different weightings within the same beam orientation to achieve better dose uniformity. This method employs the multileaf collimator to create smaller fields within the primary field, each with optimized beam weights. Field-in-field techniques are particularly useful for treating curved surfaces like the chest wall or when trying to reduce hot spots in conventional 3D conformal plans. The technique provides improved dose homogeneity compared to open fields while being simpler to plan and deliver than full inverse-planned IMRT.
Usage
Usage note: Always hyphenate; capitalize each component when used as a proper technique name.
In Context
- "Field-in-field planning reduced the hot spot from 115% to 107%." — Treatment planning report
- "The breast treatment used field-in-field technique for improved homogeneity." — Treatment summary