Lars Ewell

Effectiveness of image-guided radiotherapy for laryngeal sparing in head and neck cancer

We would like to compare the effectiveness of image-guided (IGRT) and intensity-modulated (IMRT) radiotherapy to spare the larynx in head and neck cancer patients. A retrospective review of 48 patients undergoing radiation for non-laryngeal and non-hypopharyngeal head and neck cancers. Mean laryngeal and hypopharyngeal dose was compared between 11 patients treated with IMRT and 37 patients treated with IGRT. Mean laryngeal dose was, respectively, 41.2 Gy and 22.8 Gy for the IMRT and IGRT technique (p<0.001). The radiation dose to the middle and inferior pharyngeal muscles was also significantly reduced with the IGRT technique. Mean pharyngeal dose was, respectively, 52 Gy and 26 Gy for the IMRT and IGRT technique (p=0.0001). Laryngeal sparing IGRT technique for head and neck cancer minimizes radiotherapy dose to the larynx and pharynx without sacrificing target coverage, even in the presence of neck lymph nodes.

Effectiveness of intensity-modulated and image-guided radiotherapy to spare the mandible from excessive radiation

We would like to assess the effectiveness of intensity-modulated radiotherapy (IMRT) or image-guided radiotherapy (IGRT) to decrease the risk of osteoradionecrosis in locally advanced head and neck cancer. We conducted a retrospective study of 83 patients with head and neck cancer undergoing concurrent definitive chemoradiation, post-operative radiotherapy or chemoradiation, or radiotherapy alone with IMRT or IGRT. Mean mandibular dose was, respectively, 43.6Gy and 43.8Gy for the IMRT and IGRT technique. At a median follow-up of 28 months (5-55 months), only one patient developed osteoradionecrosis requiring hyperbaric oxygen. Sharp dose falloff associated with IMRT and IGRT decreased excessive radiation of the mandible and may reduce the risks of osteoradionecrosis.

Feasibility of tomotherapy for Graves’ ophthalmopathy

PurposeTo compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens.Patients and MethodsA retrospective review of 7 patients with Graves’ ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT.ResultsCompared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands.ConclusionTomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique.ZusammenfassungZielVergleich zwischen Dosimetrie der Tomotherapie und der konventionellen Half-beam-Technik (HBT) oder Non-split-beam-Technik (NSBT) für die Erfassung des Zielvolumens und der Strahlendosis an Tränendrüsen und Linse.Patienten und MethodenEine retrospektive Analyse von 7 Patienten mit Graves’ Ophthalmopathie, die wegen Progression der Erkrankung zur Notwendigkeit hochdosierter Steroidgabe eine Strahlentherapie erhielten. 3 Patienten wurden mit Tomotherapie und 4 Patienten mit HBT behandelt.ErgebnisseIm Vergleich zu HBT konnte die Tomotherapie bessere Erfassung des Zielvolumens und signifikante Reduktion der Strahlendosis an den Tranendrüsen sowie eine höhere Strahlendosis an der Linse erreichen. NSBT verbesserte die Erfassung des Zielvolumens, resultierte aber in signifikant höherer Strahlendosis an Linse und Tränendrüsen.SchlussfolgerungTomotherapie kann – verglichen mit konventioneller Strahlentherapietechnik – zu besserer Erfassung des Zielvolumens und wirksamerer Verminderung des schweren Exophthalmus führen.

Feasibility of tomotherapy for Graves' ophthalmopathy: Dosimetry comparison with conventional radiotherapy.

PurposeTo compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens.Patients and MethodsA retrospective review of 7 patients with Graves’ ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT.ResultsCompared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands.ConclusionTomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique.ZusammenfassungZielVergleich zwischen Dosimetrie der Tomotherapie und der konventionellen Half-beam-Technik (HBT) oder Non-split-beam-Technik (NSBT) für die Erfassung des Zielvolumens und der Strahlendosis an Tränendrüsen und Linse.Patienten und MethodenEine retrospektive Analyse von 7 Patienten mit Graves’ Ophthalmopathie, die wegen Progression der Erkrankung zur Notwendigkeit hochdosierter Steroidgabe eine Strahlentherapie erhielten. 3 Patienten wurden mit Tomotherapie und 4 Patienten mit HBT behandelt.ErgebnisseIm Vergleich zu HBT konnte die Tomotherapie bessere Erfassung des Zielvolumens und signifikante Reduktion der Strahlendosis an den Tranendrüsen sowie eine höhere Strahlendosis an der Linse erreichen. NSBT verbesserte die Erfassung des Zielvolumens, resultierte aber in signifikant höherer Strahlendosis an Linse und Tränendrüsen.SchlussfolgerungTomotherapie kann – verglichen mit konventioneller Strahlentherapietechnik – zu besserer Erfassung des Zielvolumens und wirksamerer Verminderung des schweren Exophthalmus führen.

Effectiveness of prophylactic retropharyngeal lymph node irradiation in patients with locally advanced head and neck cancer

BackgroundThe aim of the study is to assess the effectiveness of intensity-modulated radiotherapy (IMRT) or image-guided radiotherapy (IGRT) for the prevention of retropharyngeal nodal recurrences in locally advanced head and neck cancer.MethodsA retrospective review of 76 patients with head and neck cancer undergoing concurrent chemoradiation or postoperative radiotherapy with IMRT or IGRT who were at risk for retropharyngeal nodal recurrences because of anatomic site (hypopharynx, nasopharynx, oropharynx) and/or the presence of nodal metastases was undertaken.The prevalence of retropharyngeal nodal recurrences was assessed on follow-up positron emission tomography (PET)-CT scans.ResultsAt a median follow-up of 22 months (4–53 months), no patient developed retropharyngeal nodal recurrences.ConclusionProphylactic irradiation of retropharyngeal lymph nodes with IMRT or IGRT provides effective regional control for individuals at risk for recurrence in these nodes.

Therapy operating characteristic (TOC) curves and their application to the evaluation of segmentation algorithms

This paper presents a general framework for assessing imaging systems and image-analysis methods on the basis of therapeutic rather than diagnostic efficacy. By analogy to receiver operating characteristic (ROC) curves, it introduces the Therapy Operating Characteristic or TOC curve, which is a plot of the probability of tumor control vs. the probability of normal-tissue complications as the overall level of a radiotherapy treatment beam is varied. The proposed figure of merit is the area under the TOC, denoted AUTOC. If the treatment planning algorithm is held constant, AUTOC is a metric for the imaging and image-analysis components, and in particular for segmentation algorithms that are used to delineate tumors and normal tissues. On the other hand, for a given set of segmented images, AUTOC can also be used as a metric for the treatment plan itself. A general mathematical theory of TOC and AUTOC is presented and then specialized to segmentation problems. Practical approaches to implementation of the theory in both simulation and clinical studies are presented. The method is illustrated with a a brief study of segmentation methods for prostate cancer.

Feasibility of Tomotherapy-based image-guided radiotherapy for small cell lung cancer

Background: To assess the tolerance of patients with small cell lung cancer undergoing chemoradiation with tomotherapy-based image-guided radiotherapy (IGRT). Materials and Methods: A retrospective review of the toxicity profile for nine patients with small cell lung cancer of the limited stage who underwent chemoradiation delivered with helical tomotherapy (HT) has been conducted. Results: Acute grade 3–4 hematologic and esophagitis toxicities developed in two and three patients respectively. One patient developed a pulmonary embolism during radiotherapy. Seven patients had weight loss ranging from 0 to 30 pounds (median: 4 pounds). Three patients had treatment breaks ranging from 2 to 12 days. At a median follow-up of 11 months (range: 2–24 months), no patients developed any radiation related toxicities such as grade 3–4 pneumonitis or other long-term complications. The median survival was estimated to be 15 months. There were two local recurrences, three mediastinal recurrences, and six distant metastases. Conclusion: Grade 3–4 toxicities remained significant during chemoradiation when radiation was delivered with tomotherapy-based IGRT. However, the absence of grade 3–4 pneumonitis is promising and the use of HT needs to be investigated in future prospective studies.

Feasibility of tomotherapy for Graves’ ophthalmopathy@@@Wirksamkeit der Tomotherapie von Ophthalmopathie bei Morbus Basedow: Dosimetry comparison with conventional radiotherapy

PurposeTo compare the dosimetry of tomotherapy and the conventional half-beam technique (HBT) or non-split beam technique (NSBT) for target coverage and radiation dose to the lacrimal glands and lens.Patients and MethodsA retrospective review of 7 patients with Graves’ ophthalmopathy who had radiotherapy because of disease progression on high steroid dose is reported: 3 patients were treated with tomotherapy and 4 patients with HBT.ResultsCompared to HBT, tomotherapy may provide better target coverage and significant reduction of radiation dose to the lacrimal glands and a higher dose to the lens. The NSBT improved target coverage but resulted in significantly higher doses to the lens and lacrimal glands.ConclusionTomotherapy may provide better coverage of the target volume and may be more effective in reducing severe exophthalmos compared to the conventional radiotherapy technique.ZusammenfassungZielVergleich zwischen Dosimetrie der Tomotherapie und der konventionellen Half-beam-Technik (HBT) oder Non-split-beam-Technik (NSBT) für die Erfassung des Zielvolumens und der Strahlendosis an Tränendrüsen und Linse.Patienten und MethodenEine retrospektive Analyse von 7 Patienten mit Graves’ Ophthalmopathie, die wegen Progression der Erkrankung zur Notwendigkeit hochdosierter Steroidgabe eine Strahlentherapie erhielten. 3 Patienten wurden mit Tomotherapie und 4 Patienten mit HBT behandelt.ErgebnisseIm Vergleich zu HBT konnte die Tomotherapie bessere Erfassung des Zielvolumens und signifikante Reduktion der Strahlendosis an den Tranendrüsen sowie eine höhere Strahlendosis an der Linse erreichen. NSBT verbesserte die Erfassung des Zielvolumens, resultierte aber in signifikant höherer Strahlendosis an Linse und Tränendrüsen.SchlussfolgerungTomotherapie kann – verglichen mit konventioneller Strahlentherapietechnik – zu besserer Erfassung des Zielvolumens und wirksamerer Verminderung des schweren Exophthalmus führen.