Lowering Whole-Body Radiation Doses in Pediatric Intensity-Modulated Radiotherapy Through the Use of Unflattened Photon Beams;Flattening filter; Pediatric; Intensity-modulated radiotherapy; Second cancers; Radiation-induced malignancies

Journal Article · Fri Jul 15 04:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2010.10.002· OSTI ID:21587620

Cashmore, Jason ^[1]; Ramtohul, Mark ^[1]; Ford, Dan ^[2]

---

1. Radiotherapy Physics, Hall-Edwards Radiotherapy Research Group, University Hospital Birmingham, Edgbaston, Birmingham (United Kingdom)
2. Cancer Centre, Hall-Edwards Radiotherapy Research Group, University Hospital Birmingham, Edgbaston, Birmingham (United Kingdom)

Purpose: Intensity modulated radiotherapy (IMRT) has been linked with an increased risk of secondary cancer induction due to the extra leakage radiation associated with delivery of these techniques. Removal of the flattening filter offers a simple way of reducing head leakage, and it may be possible to generate equivalent IMRT plans and to deliver these on a standard linear accelerator operating in unflattened mode. Methods and Materials: An Elekta Precise linear accelerator has been commissioned to operate in both conventional and unflattened modes (energy matched at 6 MV) and a direct comparison made between the treatment planning and delivery of pediatric intracranial treatments using both approaches. These plans have been evaluated and delivered to an anthropomorphic phantom. Results: Plans generated in unflattened mode are clinically identical to those for conventional IMRT but can be delivered with greatly reduced leakage radiation. Measurements in an anthropomorphic phantom at clinically relevant positions including the thyroid, lung, ovaries, and testes show an average reduction in peripheral doses of 23.7%, 29.9%, 64.9%, and 70.0%, respectively, for identical plan delivery compared to conventional IMRT. Conclusions: IMRT delivery in unflattened mode removes an unwanted and unnecessary source of scatter from the treatment head and lowers leakage doses by up to 70%, thereby reducing the risk of radiation-induced second cancers. Removal of the flattening filter is recommended for IMRT treatments.

• OSTI ID: 21587620
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 4 Vol. 80; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BEAMS
BODY
DISEASES
DOSES
ENDOCRINE GLANDS
FEMALE GENITALS
GLANDS
GONADS
HAZARDS
HEAD
LUNGS
MALE GENITALS
MEDICINE
MOCKUP
NEOPLASMS
NUCLEAR MEDICINE
ORGANS
OVARIES
PEDIATRICS
PHANTOMS
PHOTON BEAMS
RADIATION DOSES
RADIOLOGY
RADIOTHERAPY
RESPIRATORY SYSTEM
STRUCTURAL MODELS
TESTES
THERAPY
THYROID