Irradiation Methods for Accurate Dose Delivery to Postoperative Keloid Scars With Minimal Normal Tissue Exposure Using TomoTherapy: A Phantom Study.

BACKGROUND/AIM: We aimed to clarify the TomoTherapy irradiation method for accurate dose delivery to the postoperative ear keloid with minimal exposure.

MATERIALS AND

METHODS

An electron beam of Elekta synergy and static and helical photon beams of TomoTherapy were delivered to the auricle and lobe of an anthropomorphic phantom compensated using a soft rubber bolus. The doses to the ear surface and the eyeballs and thyroid were measured using radiochromic film and glass dosimeters, respectively.

RESULTS

Using static, helical, and electron beams, the respective doses to the ear surface were 97.9%, 103.0%, and 91.7% of the prescribed dose; the respective doses to the thyroid were 0.6, 0.8, and 2.4 cGy; the respective doses to the left eyeball were 3.3, 6.9, and 2.7 cGy.

CONCLUSION

The static beam of the TomoTherapy can be safely used for treating ear keloids, while ensuring target dose. The helical photon beam spreads out the low-dose exposure.