There are now applicators for treating skin cancer using HDR (high dose rate Iridium devices). Some of those available for use with the Nucletron HDR are noted here.
HDR for Skin Cancer dose, here, protocols: #1, #2

Common dose protocols for using the Valencia or Leipzig would be 7Gy X 6 treated qod so the treatment rather than taking 5 - 6 weeks is done in 6 trips over two weeks. The depth dose charts are very superficial like 50KvP with rapid fall off after 3mm treat to 3mm depth and not for lesions deeper than 4mm. Estimate controls rates of 92%


Valencia applicator

        Valencia isodose pattern

The Valencia has a flattening filter, so the dose rate is slower but the beam has flatter edges. So the 3cm diameter will treat a 2.5 cm lesion. The Leipzig is faster but the isodoses pull in. So use 3cm diameter for 2cm lesion, 2cm diameter for 1.5cm lesion and 1cm for 0.5 cm

Leipzig  applicators

       Leipzig isodose

For large lesions on the side of the face or areas that wrap around irregular surfaces, then the Freiberg Flap can be used...the so protocol here is 4.85Gy X 10 again treated every other day

 

Dose protocols from Essentials in Brachytherapy. May 17, 2008, Orlando FL.  Michael E. Kasper

Freiberg Flap

  

The indications for and results of HDR afterloading therapy in diseases of the skin and mucosa with standardized surface applicators (the Leipzig applicator)

Köhler-Brock A, Strahlenther Onkol. 1999 Apr;175(4):170-4   Klinik und Poliklinik für Strahlentherapie und Radioonkologie, Universität Leipzig.

BACKGROUND: In our department we have developed a standardized applicator for HDR brachytherapy of surface lesions, the so called Leipzig-applicator. We have used this method since September 1987, initially with a Decatron remote afterloading machine, but more recently from November 1990 with a microSelectron-HDR. We report about our experience of 10 years. PATIENTS AND METHOD:

Since 1987 we treated 520 patients in 3,026 fractions with this method. In most of the cases we irradiated tumors of the skin of the face, but we also treated tumors of the mouth, of the tongue, of the perianal region and the external genitalia. The histological types were in most of the cases squamous cell carcinomas and basal cell carcinomas, but we also treated tumors like Kaposi-sarcomas, melanomas and skin manifestations of lymphomas and solid organ tumors. We also irradiated benign lesions like keloids after excision. We use single doses between 5 and 10 Gy once to twice a week. The isodose distribution was depending of the tissue infiltration of the tumor. The total dose was 30 to 40 Gy. RESULTS: In 91% of the cases we obtained a complete remission of the tumor, in 6% a partial remission. Recurrences appeared in 8% of the patients. In most cases the reason of the recurrence was a lower brachytherapy dose because of a prior radiotherapy. We didn't observe any severe late radiation reaction. CONCLUSION: We consider that our series of patients treated with HDR brachytherapy and a range of standardized applicators demonstrates that this is a successful method of treating surface lesions.