TECHNIQUE OF AFTERLOADING INTERSTITIAL IMPLANTS

Abstract

Interstitial implants are removable or permanent (and occasionally a combination of both). Permanent implants are utilized where tumors are not accessible enough to permit easy removal of sources or where accurate source distribution is less critical. They are useful for cancers of the lung, pancreas, prostate, bladder, lymph nodes, etc. Radon and 198Au were replaced by 125I. Major interests are in removable after loading 192Ir implant techniques. Template (steel guide) and nontemplate (plastic tube) techniques are utilized. Templates are preferred where the tumor volume can only be approached from 1 side and where accurate positioning of sources would otherwise be diffucult. They are useful for human cancers of the cervix, vagina, urethra and rectum. Nontemplate (plastic tube) techniques are preferred where the tumor volume can be approached from at least 2 sides and where templates are not feasible or not essential for accurate positioning of sources. The single needle nontemplate approach is useful for cancers of lip, nodes and breast (plastic button) and cancers of the oral cavity and oropharynx (Au button). The paired needle nontemplate approach is useful for cancers of the gum, retromolar trigone and base of tongue (loop technique) and cancers of the palate (arch technique). Procedures for each technique are described in detail.