Preventing Complications from High-Dose Rate Brachytherapy when Treating Mobile Tongue Cancer via the Application of a Modular Lead-Lined Spacer

Abstract

PurposeTo point out the advantages and drawbacks of high-dose rate brachytherapy in the treatment of mobile tongue cancer and indicate the clinical importance of modular lead-lined spacers when applying this technique to patients.MethodsFirst, all basic steps to construct the modular spacer are shown. Second, we simulate and evaluate the dose rate reduction for a wide range of spacer configurations.ResultsWith increasing distance to the source absorbed doses dropped considerably. Significantly more shielding was obtained when lead was added to the spacer and this effect was most pronounced on shorter (i.e. more clinically relevant) distances to the source.ConclusionsThe modular spacer represents an important addition to the planning and treatment stages of mobile tongue cancer using HDR-ISBT.

The Efficacy of a Custom-Made Mouthpiece With Spacer to Reduce Osteoradionecrosis in Carbon-Ion Radiation Therapy for Tongue-Base Tumor

“… 3 , 4 , 9 Spacers have been employed in brachytherapy for tongue squamous cell carcinomas, reducing irradiation of the mandibular bone. 3 , 4 Murakami et al 3 reported the efficacy of modular, lead-lined spacers in the prevention of complications in high-dose-rate brachytherapy for mobile tongue cancer. When a 2-mm lead shield was added to the modular spacer, significantly more shielding was obtained, with absorbed doses reduced by 79%.…”

“…CIRT is principally offered for treatment of radioresistant tumors, such as salivary gland carcinoma and mucosal melanoma 6 . Squamous cell carcinomas, the most common of oral cancers, are well indicated for brachytherapy and photon RT with and without chemotherapy 3, 4, 9. Spacers have been employed in brachytherapy for tongue squamous cell carcinomas, reducing irradiation of the mandibular bone 3, 4.…”

“…Spacers are widely used to prevent ORN in brachytherapy for tongue cancer. 3 , 4 However, with regard to external photon radiation therapy (RT) for tongue carcinoma, there have been no reports on the utility of spacers focused on prevention of ORN, perhaps because of the dose distribution inherent to photon RT. CIRT offers improved lateral dose distribution with minimal target exit dose 1 and thereby may benefit from the employment of a spacer-including mouthpiece.…”

“…Spacers are widely used to prevent ORN in brachytherapy for tongue cancer 3, 4. However, with regard to external photon radiation therapy (RT) for tongue carcinoma, there have been no reports on the utility of spacers focused on prevention of ORN, perhaps because of the dose distribution inherent to photon RT.…”

A new implant device to prevent edema-associated underdosage in high-dose-rate interstitial brachytherapy of mobile tongue cancer

“…For DVH-based OARs evaluation, we use the minimum dose received by the maximally irradiated 2 cc (D 2cc ) of the mandible. For this, we use lead blocks as spacers and shielding devices to the gingival mucosa and mandible for protection purposes [17]. For CT planning, however, we use silicone blocks instead of lead blocks to prevent metal artifacts ( Figure 2B).…”