Conformal rotation therapy with central axis beam block is a feasible alternative to intensity-modulated radiotherapy for chordomas of the cervical spine.

Aims: Paraspinal tumours, such as chordoma, represent a treatment challenge for oncologists, requiring high dose to the target volume without exceeding the tolerance dose of the spinal cord. Intensity-modulated radiotherapy (IMRT) is helpful in achieving sharp dose gradients and conformation of dose to the target volume. We present a simpler technique--conformal rotation therapy with a central axis beam block (CRT + BB), which can provide similar dose distributions.

Absorbed dose behind eye shields during kilovoltage photon radiotherapy.

The absorbed dose at the position of the lens of the eye under lead or tungsten eye shields during kilovoltage photon radiotherapy is critically dependent not so much on the thickness of the eye shield itself as on the size of the treatment field and the diameter of the shield used. Whilst dose from primary photons is easily attenuated to relatively insignificant levels by a few millimetres of lead or tungsten, scattered photons from outside the shielded area can provide over 25% of the prescribed dose. Since backscatter factors do not increase monotonically with photon energy, it is not safe to assume that the highest photon energy used will provide the highest dose.