The range of conditions which can be treated using kilovoltage X-Ray therapy treatment is wide and includes, most commonly, basal cell carcinoma and squamous cell carcinoma. Detailed information concerning treatment of both benign and malignant conditions can be found in the Physics of Low Energy X-Rays topic section, X-Rays in the energy range 10 kV to 300 kV are most suitable for treating skin lesions as they impart most of their energy at the skin surface or a few millimetres below the skin surface. In the clinical setting Kilovoltage therapeutic X–Rays are conveniently divided into four areas:
- Grentz rays; energy range 10 to 12 kV which are commonly used in some centres, particularly in Europe.
- Contact therapy; 50 kV range, short source surface distance (SSD) units commonly less than 5 cm FSD.
- Superficial therapy; energy range 50 to 150 kV with typical half value layers (HVLs) in the range of 1 to 8 mm Al. The FSD is normally 10 to 30 cm. The beam characteristics of such X-Ray energies are suitable for treatment of lesions up to 5 mm deep, delivering 90% of the dose to the surface.
- Orthovoltage therapy; energy range 150 to 300 kV with FSD of approximately 50 cm. The beam characteristics of such X-Ray energies are suitable for treatment of thicker lesions, delivering 90% of the dose within approximately 2 cm of the skin surface.
Dosage & Fractionation
Many different regimes; doses and fraction schedules are used in the UK, this topic section contains information on the author’s preferred treatment regimes, used in the UK.