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We investigated a risk of developing radiation myelitis during four prospective studies using hyperfractionated radiation therapy (HFX RT) with and without concurrent chemotherapy (CHT) during which a portion of thoracic spinal cord received a dose ≥50.4 Gy given via 1.2 Gy b.i.d. fractionation. Of 536 patients with Stage III non-small cell lung cancer (NSCLC) which were treated on three prospective randomised Phase III studies and one Phase II study, 336 patients received irradiation dose ≥50.4 Gy to a portion of their spinal cord and survived >1 year after the beginning of therapy. None of these 336 patients developed thoracic radiation myelitis. Therefore, the influence of potentially contributing factors on the occurrence of radiation myelitis, such as cord length, interfraction interval, or administration of concurrent CHT was not possible to investigate. These results give new insight about the influence of total dose/dose per fraction/interfraction interval with or without concurrent CHT on the thoracic spinal cord toxicity. [Copyright &y& Elsevier]

Abstract: Positron Emission Tomography (PET) is a significant advance in cancer imaging with great potential for optimizing radiation therapy (RT) treatment planning and thereby improving outcomes for patients. The use of PET and PET/CT in RT planning was reviewed by an international panel. The International Atomic Energy Agency (IAEA) organized two synchronized and overlapping consultants’ meetings with experts from different regions of the world in Vienna in July 2006. Nine experts and three IAEA staff evaluated the available data on the use of PET in RT planning, and considered practical methods for integrating it into routine practice. For RT planning, 18F fluorodeoxyglucose (FDG) was the most valuable pharmaceutical. Numerous studies supported the routine use of FDG-PET for RT target volume determination in non-small cell lung cancer (NSCLC). There was also evidence for utility of PET in head and neck cancers, lymphoma and in esophageal cancers, with promising preliminary data in many other cancers. The best available approach employs integrated PET/CT images, acquired on a dual scanner in the radiotherapy treatment position after administration of tracer according to a standardized protocol, with careful optimization of images within the RT planning system and carefully considered rules for contouring tumor volumes. PET scans that are not recent or were acquired without proper patient positioning should be repeated for RT planning. PET will play an increasing valuable role in RT planning for a wide range of cancers. When requesting PET scans, physicians should be aware of their potential role in RT planning. [Copyright &y& Elsevier]