Table 1.

Brachytherapy applicators used for treatment of gynecological cancers

Intracavitary brachytherapy (ICBT) applicators
Tandem and ovoid (TO) or Fletcher suit (FS) type applicator ICBT	Consists of uterine tube (central tandem) and 2 colpostats. Various angles of central tandems and various sizes of colpostats are commercially available. It is a semi-fixed applicator made of stainless steel or CT/MR compatible acrylic material or titanium alloy It is one of the most commonly used applicators, designed to deliver adequate doses to uterus/cervix, upper vagina (2-2.5 cm) and medial parametrium by a standard pear-shaped dose distribution
Tandem and ring (TR) applicator – ICBT	Consists of uterine tube and a ring as vaginal source carrier. It is a fixed geometry stainless steel or CT/MRI compatible applicator and has similar dose distribution properties as those of the TO applicator. The ring provides an additional degree of freedom to load the vaginal sources over the ovoids. However, there are no substantial data to suggest the dosimetric difference between TO and ring applicator
Tandem with vaginal cylinders – ICBT	Consists of central tandem and vaginal cylinders available in various diameter sizes Cylinders are used in cases of narrow conical vagina where ovoids/ring are difficult to accommodate or in cases of residual disease extending beyond the upper vagina. The dose distribution is cylindrical. As there is a single source channel, lateral throw off of dose in to the parametrium is less as compared to ovoids/ring
Intracavitary and interstitial (IC + IS) applicators
TR with interstitial needles (Vienna applicator) – IC + IS	It is based on a MRI compatible tandem with ring with an array of holes in the surface of the ring for insertion of needles/tubes into the medial parametrium. Hence it provides a template at the level of the vaginal fornices to insert needles/tubes into the parametrium. These needles when loaded improve the lateral dose throw off by another 1.5 cm to treat additional parametrium [20]
TO with interstitial needles (Utrecht applicator) – IC + IS	On similar principles as the Vienna applicator for IC + IS, the Utrecht applicator has holes in the ovoids to insert needles into the parametrium to improve coverage beyond point A
Venezia applicator	Consists of central tandem, ovoids/two ring halves that can accommodate straight or diverging interstitial parametrial needles and a detachable perineal template. The applicator is designed for the treatment of advanced disease with involvement of lateral parametrium with the modified ovoid/ring 2 halves system and/or lower vagina or paracolpos with the perineal template
Interstitial templates
Syed-Neblett GYN Template	Consists of perineal template with provision for central vaginal cylinder and tandem when required. The template provides an array of holes to insert needles/tubes through the perineum in a butterfly shaped positions
Martinez Universal Perineal Interstitial Template (MUPIT)	The device consists of an acrylic perineal template with a predrilled array of holes to guide passage of straight and divergent needles, and the cylindrical obturator. Number of needles, depth of insertion, angle and positions of needles determine the dose distribution characteristics and can be used to treat the desired target area in the pelvis. The needles can be secured for individual movements with the help of screws and a reinforcement plate