Curative radiotherapy for early cancers of the lip, buccal mucosa, and nose--a simple interstitial brachytherapy technique employing angiocatheters as carriers for Iridium-192 wire implants.

OBJECTIVES: To evaluate treatment outcomes following interstitial brachytherapy for cancers of the lip, buccal mucosa, or nose. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: A cohort of 13 patients treated uniformly by a simple interstitial brachytherapy technique employing plastic angiocatheters as carriers for Iridium-192 wires: all but one patient had T1 or T2 tumours and all but one had N0 disease. MAIN OUTCOME MEASURES: Local and loco-regional control rates. RESULTS: Six of the 13 patients received external radiotherapy prior to interstitial brachytherapy. A median brachytherapy dose of 70 Gy was delivered to those treated with brachytherapy alone, while 35 Gy was delivered after a median external radiotherapy dose of 50 Gy to those receiving combined treatment. The 3-year actuarial local control rate was 75%. No significant late complications were observed. CONCLUSIONS: Employing a simple brachytherapy technique using angiocatheters and Iridium-192 wires, in conjunction with external radiotherapy when appropriate, produces good outcomes for patients with early lip, nasal vestibule, and buccal mucosa cancers.

The electron-dose distribution surrounding an 192Ir wire brachytherapy source investigated using EGS4 simulations and GafChromic film.

The steep dose gradient around 192Ir brachytherapy wire implants is predicted by the EGS4 (PRESTA version) Monte Carlo simulation. When considering radiation absorbing regions close to the wire source, the accurate dose distribution cannot be calculated by the GE Target II Sun Sparc treatment-planning system. Experiments using GafChromic film have been performed to prove the validity of the EGS4 user code when calculating the dose close to the wire source in a low energy range.