Pulsed-protracted Irradiation to Overcome Radioresistance

Krueger, S.A.; Schoenherr, D.; Park, S.; Martínez, Álvaro; Wilson, George; Marples, Brian

doi:10.1016/j.ijrobp.2010.07.1467

Cited by 4 publications

(6 citation statements)

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“…Low-dose hyper-radiosensitivity Low-dose hyper-radiosensitivity (HRS) is a radiobiological phenomenon observed in the survival curves of many cell lines at low doses. For example, when the linear-quadratic (LQ) model is fitted to survival curves for doses <0.5 Gy, the α parameter is much larger than the value found when it is fitted for doses 1 Gy (Hall and Brenner 1991, Singh et al 1994, Short et al 2001, Harney et al 2004a, 2004b, Wykes et al 2006, Marples and Collis 2008, Dai et al 2009, Krueger et al 2010. Figure 1 illustrates low-dose HRS in T98G human glioma cells (Joiner et al 2001).…”

Section: Radiobiological Basismentioning

confidence: 99%

Pulsed low dose-rate radiotherapy: radiobiology and dosimetry

Charlie¹

2022

Phys. Med. Biol.

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Pulsed low dose-rate radiotherapy (PLDR) relies on two radiobiological findings, the hyper-radiosensitivity of tumor cells at small doses and the reduced normal tissue toxicity at low dose rates. This is achieved by delivering the daily radiation dose of 2 Gy in 10 sub-fractions (pulses) with a 3-minute time interval, resulting in an effective low dose rate of 0.067 Gy/minute. In vitro cell studies and in vivo animal experiments demonstrated the therapeutic potential of PLDR treatments and provided useful preclinical data. Various treatment optimization strategies and delivery techniques have been developed for PLDR on existing linear accelerators. Preliminary results from early clinical studies have shown favorable outcomes for various treatment sites especially for recurrent cancers. This paper reviews the experimental findings of PLDR and dosimetric requirements for PLDR treatment planning and delivery, and summarizes major clinical studies on PLDR cancer treatments.

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Section: Radiobiological Basismentioning

confidence: 99%

Pulsed low dose-rate radiotherapy: radiobiology and dosimetry

Charlie¹

2022

Phys. Med. Biol.

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“…Low-dose hyper-radiosensitivity (LDHRS) has been found in many cell lines of both tumor and some normal tissues, as well as in human metastatic tumors [28][29][30][31][32][33][34][35][36]. LDHRS was not observed in the intrinsically radiosensitive cell lines, whereas radioresistant cell lines demonstrated the most marked LDHRS [37,38].…”

Section: The Pldr Techniquementioning

confidence: 99%

“…LDHRS was not observed in the intrinsically radiosensitive cell lines, whereas radioresistant cell lines demonstrated the most marked LDHRS [37,38]. A possible explanation for LDHRS is the lack of DNA repair below a given threshold dose (transition dose), which is cell-type dependent and has been typically observed in the dose range of 0.2 Gy to 0.6 Gy [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. In contrary to normal tissue sparing due to repair of sublethal DNA damage during low dose-rate irradiation, increased radiosensitivity of tumor cells was observed when the dose-rate was decreased.…”

Section: The Pldr Techniquementioning

confidence: 99%

Clinical Applications of Pulsed Low Dose-Rate Radiation Therapy

Chen¹

2021

Mathews Journal of Cancer Science

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Pulsed low dose-rate radiotherapy (PLDR) is a novel radiotherapy technique for cancer treatments, which relies on two radiobiological findings, the hyper-radiosensitivity of tumor cells at small doses and the reduced normal tissue toxicity at low dose rates. PLDR delivers the daily radiation dose in a number of sub-fractions (pulses) with a preset time interval to achieve an effective low dose rate. PLDR can be delivered on existing clinical machines using different treatment optimization strategies and delivery techniques. Clinical trials have been carried out to study the application of PLDR for various cancers especially for recurrent cancers. Preliminary results from these clinical studies have shown favorable outcome. This paper briefly describes the PLDR technique, the planning requirements and its clinical applications in cancer treatment.

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“…4,5 The idea behind the PRDR technique is to take advantages of both the hyper-radiosensitivity of tumor cells below their transition doses, which are generally greater than those of normal tissues, and the increased normal tissue repair at low dose rates. 6,7 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 radiation repair is triggered in normal tissues but not in tumor cells.…”

Section: Overviewmentioning

confidence: 99%