(a) A tandem and ovoid with interstitial catheters (Utrecht applicator, Nucletron B.V., Veenendaal, Netherlands). The applicator uses interstitial catheters that extend above the ovoids and cover a greater width of the cervix higher up than standard ovoids. (b) A tandem and ring applicator with interstitial catheters inserted (Vienna applicator, Nucletron B.V., Veenendaal, Netherlands). Catheters similar to the Utrecht applicator extend the dose to a greater height and width than without. Care must be taken to dose only approximately 10% through the needles, allowing the majority of the dose contribution to be from the tandem and ovoids.