Methodological aspects of renography in children.

Kidney function in children by renography has been evaluated. For reproducible results a high degree of standardization with respect to position, hydration and dosage was necessary. The wide range of kidney size and depth in children requires age-adapted collimators. For practical use for different size have been constructed for the age-groups: less 1 year, 1-5 years, 6-9 years and 10-15 years. A reduction in the surrounding activity of the kidneys is thereby obtained and disturbing influence from the bladder or contralateral kidney is prevented. Kidney function variables from the renogram are presented in terms of uptake and excretion ratios. The correlation between sum of uptake ratios and clearance measurements is good in cases with slight or moderate difference in kidney size. The standardized renographic technique has many advantages for kidney function measurements in children. The method is applicable in all ages, it is simple and reliable without extensive preparations and requires a low radiation dose. Also in children we can confirm the previous opinion obtained in adults that renography is a clinical valuable method of measuring kidney function.