13 Oropharynx

Oropharynx 279

As for tumours of the mobile tongue, the above described classical plastic loop technique may be unsuitable for stepping source afterloaders because the stepping source cannot take very bended loops. In that case, straight-blinded plastic tubes are implanted with a 15 - 20 mm interneedle spacing in a square pattern. Six to nine tubes are usually required for covering the target. The nylon filament, which is connected to the implantation tube, is inserted into the needle through its intra- oropharyngeal end. Then, the needle is withdrawn, and the tube is gently pulled through the tongue and the skin. It is advised to prepare nylon tube spacers, which will hold the blind ends of the tubes in a correct position, before inserting the nylon filaments into the guide needles. Vallecular region The loop technique can be modified for implanting vallecular tumours. The posterior inferior branches of the loops are implanted between the hyoid bone and the thyroid cartilage through the epiglottis, and the superior branches into the base of tongue. When the loops are formed, the free portion of the epiglottis is pulled forward and held against the base of tongue (Fig 12.3). Straight, blind-ended plastic tubes may replace loops if a stepping source afterloader is used. 7.2

7.3 Soft Palate 7.3.1 Classical Pernot technique

The procedure is carried out under general anaesthesia with nasal intubation or neurolept analgesia combined with local anaesthesia, with the patient sitting in a dental chair. Two parallel frontal loops 15 -20 mm apart are implanted to cover the whole or two thirds of the faucial arch (Fig 12.4). Fig 12.4: Pernot technique for implanting the faucial arch.

B: X-Ray control: lateral view with dummy sources

A: Soft palate plastic tubes implant: diagram C: Tomography, lateral view