Pulsed reduced dose rate radiation therapy is likely to become the treatment modality of choice for recurrent cancers

Low dose hypersensitivity following in vitro cell irradiation with charged particles: Is the mechanism the same as with X-ray radiation?

“…However attempts are currently being made to take advantage of the HRS phenomenon in X-ray radiotherapy. The pulsed reduced dose rate (PRDR) radiotherapy (Ma et al 2011) consists in delivering 10 X-ray pulses of 0.2 Gy with 3-min intervals daily, resulting in an effective dose rate of 0.067 Gy/min. The idea behind PRDR is to take advantage of both tumor cells HRS below their of lesions becomes more severe for identical doses as the LET increases, in a way that the cell can no longer ignore the damage and triggers the G 2 /M checkpoint, even when doses get weaker and weaker.…”

Optimization strategies for pulsed low‐dose‐rate IMRT of recurrent lung and head and neck cancers

“…The dose‐rate effect in radiotherapy has been investigated for many years (2,3) . Pulsed low‐dose‐rate radiotherapy (PLDR) has been used in some institutions for treatment of recurrent cancer for several years (4‐9) . The idea behind the PLDR technique is to take the advantages of both the hyperradiosensitivity of tumor cells below their transition doses above which cell repair mechanisms may be initiated to introduce radiation resistance, and the increased normal tissue repair at low‐dose rates (4) .…”

“…Pulsed low‐dose‐rate radiotherapy (PLDR) has been used in some institutions for treatment of recurrent cancer for several years (4‐9) . The idea behind the PLDR technique is to take the advantages of both the hyperradiosensitivity of tumor cells below their transition doses above which cell repair mechanisms may be initiated to introduce radiation resistance, and the increased normal tissue repair at low‐dose rates (4) . The way to achieve this is to divide a daily radiotherapy treatment into a number of subfractions (pulses), with each subfractional dose less than the tumor transition dose but greater than the normal tissue transition dose, so that the radiation repair is triggered in normal tissues but not in tumor cells.…”

External beam pulsed low dose radiotherapy using volumetric modulated arc therapy: Planning and delivery

“…A recently published point-counter-point argument also supports the possible usefulness of pulsed RT technique using external beam. 15 As used by the University of Wisconsin group, the clinical rationale of pulsed RT was to lower the treatment dose rate. [2][3][4][5][6] Their planning study demonstrated that low dose rate treatments could be achieved using linear accelerators by dividing the daily radiotherapy treatment into a number of subfractions or pulses.…”