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R Calandrino - One of the best experts on this subject based on the ideXlab platform.
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intensity modulated proton therapy versus helical tomotherapy in Nasopharynx Cancer planning comparison and ntcp evaluation
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: L Widesott, C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, Nadia Di Muzio, Ferruccio Fazio, R Calandrino, Marco SchwarzAbstract:Purpose To compare intensity-modulated proton therapy (IMPT) and helical tomotherapy (HT) treatment plans for Nasopharynx Cancer using a simultaneous integrated boost approach. Methods and Materials The data from 6 patients who had previously been treated with HT were used. A three-beam IMPT technique was optimized in the Hyperion treatment planning system, simulating a “beam scanning” technique. HT was planned using the tomotherapy treatment planning system. Both techniques were optimized to simultaneously deliver 66 Gy in 30 fractions to planning target volume (PTV1; GTV and enlarged nodes) and 54 Gy to PTV2 subclinical, electively treated nodes. Normal tissue complication probability calculation was performed for the parotids and larynx. Results Very similar PTVs coverage and homogeneity of the target dose distribution for IMPT and HT were found. The conformity index was significantly lower for protons than for photons (1.19 vs. 1.42, respectively). The mean dose to the ipsilateral and contralateral parotid glands decreased by 6.4 Gy and 5.6 Gy, respectively, with IMPT. The volume of mucosa and esophagus receiving ≥20 Gy and ≥30 Gy with IMPT was significantly lower than with HT. The average volume of larynx receiving ≥50 Gy was significantly lower with HT, while for thyroid, it was comparable. The volume receiving ≥30, ≥20, and ≥10 Gy in total body volume decreased with IMPT by 14.5%, 19.4%, and 23.1%, respectively. The normal tissue complication probability for the parotid glands was significantly lower with IMPT for all sets of parameters; however, we also estimated an almost full recovery of the contralateral parotid with HT. The normal tissue complication probability for the larynx was not significantly different between the two irradiation techniques. Conclusion Excellent target coverage, homogeneity within the PTVs, and sparing of the organs at risk were reached with both modalities. IMPT allows for better sparing of most organs at risk at medium-to-low doses.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm3 [IMRT] to 18 cm3 [HT]); larynx (V30: 25 cm3 vs. 11 cm3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm3 vs. 1 cm3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy a planning study
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:PURPOSE: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. PATIENTS AND METHODS: Six T1-4 N1-3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. RESULTS: The fraction of PTV receiving >95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p<0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p<0.05). Significant gains (p<0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm(3) [IMRT] to 18 cm(3) [HT]); larynx (V30: 25 cm(3) vs. 11 cm(3)); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm(3) vs. 1 cm(3)); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). CONCLUSION: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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Simultaneous Integrated Boost (SIB) for Nasopharynx Cancer with Helical Tomotherapy
Strahlentherapie und Onkologie, 2007Co-Authors: C Fiorino, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, Italo Dell'oca, R CalandrinoAbstract:Purpose: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Patients and Methods: Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. Results: The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm^3 [IMRT] to 18 cm^3 [HT]); larynx (V30: 25 cm^3 vs. 11 cm^3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm^3 vs. 1 cm^3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). Conclusion: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT. Ziele: Untersuchung des Potentials der helikalen Tomotherapie (HT) beim Nasopharynxkarzinom. Patienten und Methodik: Sechs T1–4 N1–3-Patienten wurden einbezogen. Eine Technik des simultanen integrierten Boost (SIB) wurde geplant mit invers optimierter konventioneller intensitätsmodulierter Radiotherapie (IMRT; dynamischer Multileaf-Kollimator des Eclipse-Helios Varian-Systems) und mit HT. Die verschriebenen (medianen) Strahlungsdosen waren 54 Gy, 61,5 Gy und 64,5 Gy, die in 30 Fraktionen auf die Planungszielvolumina PTV1, PTV2 bzw. PTV3 gegeben wurden. Bei beiden Modalitäten, HT und IMRT, wurden für die PTV-Erfassung sowie für Parotiden, Rückenmark, Kiefer, optischen Apparat und Stammhirn dieselben Begrenzungen eingehalten. Der Planer versuchte auch, die Strahlungsdosis auf andere Regionen (Mukosa außerhalb von PTV1, Larynx, Ösophagus, Innenohr, Schilddrüse, Hirn, Lunge, Bindegewebe und Knochen unterhalb des Kinns) so stark wie möglich zu reduzieren. Ergebnisse: Der PTV-Anteil, der mehr als 95% der verschriebenen Strahlungsdosis (V95%) erhielt, erhöhte sich für PTV1 und PTV3 von 97,6% bzw. 94,3% (IMRT) auf 99,6% bzw. 97% (HT) (p < 0,05); die mediane Dosis der Parotiden verminderte sich von 30,1 Gy bei IMRT auf 25,0 Gy bei HT (p < 0,05). Signifikante Vorteile (p < 0,05) zeigten sich für die meisten Risikoorgane: Mukosa (V30-Verminderung von 44 cm^3 [IMRT] auf 18 cm^3 [HT]), Larynx (V30: 25 cm^3 vs. 11 cm^3), Schilddrüse (mittlere Strahlungsdosis: 48,7 Gy vs. 41,5 Gy), Ösophagus (V45: 4 cm^3 vs. 1 cm^3), Stammhirn (D1%: 45,1 Gy vs. 37,7 Gy). Schlussfolgerung: Verglichen mit der Linac-5-Felder-IMRT verbessert HT die Homogenität der Dosisverteilung innerhalb des PTV und die PTV-Erfassung bei signifkant besserer Schonung von Risikoorganen.
C Fiorino - One of the best experts on this subject based on the ideXlab platform.
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intensity modulated proton therapy versus helical tomotherapy in Nasopharynx Cancer planning comparison and ntcp evaluation
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: L Widesott, C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, Nadia Di Muzio, Ferruccio Fazio, R Calandrino, Marco SchwarzAbstract:Purpose To compare intensity-modulated proton therapy (IMPT) and helical tomotherapy (HT) treatment plans for Nasopharynx Cancer using a simultaneous integrated boost approach. Methods and Materials The data from 6 patients who had previously been treated with HT were used. A three-beam IMPT technique was optimized in the Hyperion treatment planning system, simulating a “beam scanning” technique. HT was planned using the tomotherapy treatment planning system. Both techniques were optimized to simultaneously deliver 66 Gy in 30 fractions to planning target volume (PTV1; GTV and enlarged nodes) and 54 Gy to PTV2 subclinical, electively treated nodes. Normal tissue complication probability calculation was performed for the parotids and larynx. Results Very similar PTVs coverage and homogeneity of the target dose distribution for IMPT and HT were found. The conformity index was significantly lower for protons than for photons (1.19 vs. 1.42, respectively). The mean dose to the ipsilateral and contralateral parotid glands decreased by 6.4 Gy and 5.6 Gy, respectively, with IMPT. The volume of mucosa and esophagus receiving ≥20 Gy and ≥30 Gy with IMPT was significantly lower than with HT. The average volume of larynx receiving ≥50 Gy was significantly lower with HT, while for thyroid, it was comparable. The volume receiving ≥30, ≥20, and ≥10 Gy in total body volume decreased with IMPT by 14.5%, 19.4%, and 23.1%, respectively. The normal tissue complication probability for the parotid glands was significantly lower with IMPT for all sets of parameters; however, we also estimated an almost full recovery of the contralateral parotid with HT. The normal tissue complication probability for the larynx was not significantly different between the two irradiation techniques. Conclusion Excellent target coverage, homogeneity within the PTVs, and sparing of the organs at risk were reached with both modalities. IMPT allows for better sparing of most organs at risk at medium-to-low doses.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm3 [IMRT] to 18 cm3 [HT]); larynx (V30: 25 cm3 vs. 11 cm3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm3 vs. 1 cm3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy a planning study
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:PURPOSE: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. PATIENTS AND METHODS: Six T1-4 N1-3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. RESULTS: The fraction of PTV receiving >95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p<0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p<0.05). Significant gains (p<0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm(3) [IMRT] to 18 cm(3) [HT]); larynx (V30: 25 cm(3) vs. 11 cm(3)); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm(3) vs. 1 cm(3)); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). CONCLUSION: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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Simultaneous Integrated Boost (SIB) for Nasopharynx Cancer with Helical Tomotherapy
Strahlentherapie und Onkologie, 2007Co-Authors: C Fiorino, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, Italo Dell'oca, R CalandrinoAbstract:Purpose: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Patients and Methods: Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. Results: The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm^3 [IMRT] to 18 cm^3 [HT]); larynx (V30: 25 cm^3 vs. 11 cm^3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm^3 vs. 1 cm^3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). Conclusion: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT. Ziele: Untersuchung des Potentials der helikalen Tomotherapie (HT) beim Nasopharynxkarzinom. Patienten und Methodik: Sechs T1–4 N1–3-Patienten wurden einbezogen. Eine Technik des simultanen integrierten Boost (SIB) wurde geplant mit invers optimierter konventioneller intensitätsmodulierter Radiotherapie (IMRT; dynamischer Multileaf-Kollimator des Eclipse-Helios Varian-Systems) und mit HT. Die verschriebenen (medianen) Strahlungsdosen waren 54 Gy, 61,5 Gy und 64,5 Gy, die in 30 Fraktionen auf die Planungszielvolumina PTV1, PTV2 bzw. PTV3 gegeben wurden. Bei beiden Modalitäten, HT und IMRT, wurden für die PTV-Erfassung sowie für Parotiden, Rückenmark, Kiefer, optischen Apparat und Stammhirn dieselben Begrenzungen eingehalten. Der Planer versuchte auch, die Strahlungsdosis auf andere Regionen (Mukosa außerhalb von PTV1, Larynx, Ösophagus, Innenohr, Schilddrüse, Hirn, Lunge, Bindegewebe und Knochen unterhalb des Kinns) so stark wie möglich zu reduzieren. Ergebnisse: Der PTV-Anteil, der mehr als 95% der verschriebenen Strahlungsdosis (V95%) erhielt, erhöhte sich für PTV1 und PTV3 von 97,6% bzw. 94,3% (IMRT) auf 99,6% bzw. 97% (HT) (p < 0,05); die mediane Dosis der Parotiden verminderte sich von 30,1 Gy bei IMRT auf 25,0 Gy bei HT (p < 0,05). Signifikante Vorteile (p < 0,05) zeigten sich für die meisten Risikoorgane: Mukosa (V30-Verminderung von 44 cm^3 [IMRT] auf 18 cm^3 [HT]), Larynx (V30: 25 cm^3 vs. 11 cm^3), Schilddrüse (mittlere Strahlungsdosis: 48,7 Gy vs. 41,5 Gy), Ösophagus (V45: 4 cm^3 vs. 1 cm^3), Stammhirn (D1%: 45,1 Gy vs. 37,7 Gy). Schlussfolgerung: Verglichen mit der Linac-5-Felder-IMRT verbessert HT die Homogenität der Dosisverteilung innerhalb des PTV und die PTV-Erfassung bei signifkant besserer Schonung von Risikoorganen.
Michael J Zelefsky - One of the best experts on this subject based on the ideXlab platform.
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reirradiation of locally recurrent Nasopharynx Cancer with external beam radiotherapy with or without brachytherapy
International Journal of Radiation Oncology Biology Physics, 2010Co-Authors: Lawrence Koutcher, Dennis H Kraus, Michael J Zelefsky, David G Pfister, Kelvin Chan, Gilad N Cohen, Suzanne L WoldenAbstract:Purpose To determine survival rates of patients with locally recurrent Nasopharynx Cancer (LRNPC) treated with modern therapeutic modalities. Methods and Materials From July 1996 to March 2008, 29 patients were reirradiated for LRNPC. Thirteen patients received combined-modality treatment (CMT), consisting of external beam radiotherapy (EBRT) followed by intracavitary brachytherapy, whereas 16 received EBRT alone. The median age was 50 years, 59% were male, 38% were Asian, 69% had World Health Organization Class III histology, and 86% were treated for their first recurrence. Nine, 6, 8, and 6 patients had recurrent Stage I, II, III, and IV disease, respectively. Patients in the EBRT-alone group had more advanced disease. Median time to reirradiation was 3.9 years. In total, 93% underwent imaging with positron emission tomography and/or magnetic resonance imaging before reirradiation, 83% received intensity-modulated radiotherapy, and 93% received chemotherapy, which was platinum-based in 85% of cases. Results The median follow-up for all patients was 45 months and for surviving patients was 54 months. Five-year actuarial local control, event-free survival, and overall survival rates were 52%, 44%, and 60%, respectively. No difference was observed between patients treated with EBRT or CMT. Overall survival was superior in patients who achieved local control ( p = 0.0003). The incidence of late Grade ≥3 events in patients re-treated with EBRT alone was significantly increased compared with those receiving CMT (73% vs. 8%; p = 0.005). Conclusions In this modern reirradiation series of patients with LRNPC, favorable overall survival compared with historical series was achieved. Patients treated with CMT experienced significantly fewer severe late effects compared with those treated with EBRT.
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intensity modulated radiation therapy imrt for Nasopharynx Cancer update of the memorial sloan kettering experience
International Journal of Radiation Oncology Biology Physics, 2006Co-Authors: Suzanne L Wolden, Dennis H Kraus, David G Pfister, W C Chen, Sean L Berry, Michael J ZelefskyAbstract:Purpose: We previously demonstrated that intensity-modulated radiation therapy (IMRT) significantly improves radiation dose distribution over three-dimensional planning for Nasopharynx Cancer and reported positive early clinical results. We now evaluate whether IMRT has resulted in improved outcomes for a larger cohort of patients with longer follow-up. Methods and Materials: Since 1998, all 74 patients with newly diagnosed, nonmetastatic Nasopharynx Cancer were treated with IMRT using accelerated fractionation to 70 Gy; 59 received a hyperfractionated concomitant boost, and more recently 15 received once-daily treatment with dose painting. With the exception of Stage I disease ( n = 5) and patient preference ( n = 1), 69 patients received concurrent and adjuvant platinum-based chemotherapy similar to that in the Intergroup 0099 trial. Results: Patient characteristics: median age 45; 32% Asian; 72% male; 65% World Health Organization III; 6% Stage I, 16% Stage II, 30% Stage III, 47% Stage IV. Median follow-up is 35 months. The 3-year actuarial rate of local control is 91%, and regional control is 93%; freedom from distant metastases, progression-free survival, and overall survival at 3 years are 78%, 67%, and 83%, respectively. There was 100% local control for Stage T1/T2 disease, compared to 83% for T3/T4 disease ( p = 0.01). Six patients failed at the primary site, with median time to local tumor progression 16 months; 5 were exclusively within the 70 Gy volume, and 1 was both within and outside the target volume. There is a trend for improved local control with IMRT when compared to local control of 79% for 35 patients treated before 1998 with three-dimensional planning and chemotherapy ( p = 0.11). Six months posttherapy, 21%, 13%, 15%, and 0% of patients with follow-up audiograms ( n = 24 patients) had Grade 1, 2, 3, and 4 sensorineural hearing loss, respectively. For patients with >1 year follow-up ( n = 59), rates of long-term xerostomia were as follows: 26% none, 42% Grade 1, 32% Grade 2, and zero Grade 3. Conclusions: The pattern of primary site failure within the target volume suggests locally advanced T stage disease may require a higher biologic dose to gross tumor. Rates of severe (Grade 3–4) ototoxicity and xerostomia are low with IMRT as a result of normal-tissue protection. Distant metastases are now the dominant form of failure, emphasizing the need for improved systemic therapy.
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intensity modulated radiation therapy imrt for Nasopharynx Cancer update of the memorial sloan kettering experience
Journal of Clinical Oncology, 2005Co-Authors: W C Chen, Dennis H Kraus, Michael J Zelefsky, David G Pfister, Sean L Berry, S L WoldenAbstract:5541 Background: We previously demonstrated that IMRT significantly improves radiation dose distribution over 3-dimensional (3D) planning for Nasopharynx Cancer (NPC) and reported positive early clinical results. We now evaluate whether IMRT has resulted in improved outcomes for a larger cohort of NPC patients with longer follow-up. Methods: Since 1998, all 74 patients with newly diagnosed, nonmetastatic NPC were treated with IMRT using accelerated fractionation to 70 Gy; 59 received a hyperfractionated concomitant boost and more recently 15 received once daily treatment with dose-painting. With the exception Stage I disease (n=5) and patient refusing (n=1), 69 patients received concurrent and adjuvant platinum based chemotherapy similar to Intergroup 0099 trial. Results: Patient characteristics: median age 45; 32% Asian; 72% male; 65% WHO III; 51% Stage T3/4, 47% N2/3, and 47% Stage IV. Median follow up is 33 months. The 3-year actuarial rate of local control is 89% and regional control is 95%. Freedom f...
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Failure of a 3D conformal boost to improve radiotherapy for nasopharyngeal carcinoma.
International Journal of Radiation Oncology Biology Physics, 2001Co-Authors: Suzanne L Wolden, Dennis H Kraus, Michael J Zelefsky, David G Pfister, Margie Hunt, Kenneth E Rosenzweig, Lanceford M Chong, Steven A LeibelAbstract:Abstract Purpose: To determine whether the use of 3-dimensional (3D) boost for patients with Nasopharynx Cancer improves local control and reduces the risk of long-term complications. Methods and Materials: From 1988 to 1998, 68 patients with Nasopharynx Cancer received conventional external beam therapy followed by a 3D boost. Disease characteristics of treated patients were as follows: WHO I histology 7%, WHO II 62%, WHO III 31%, clinical AJCC stage T1–2 45%, T3–4 55%, N0–1 63%, N2–3 37%, M0 100%. The median radiation dose was 70 Gy (68–75.6 Gy). Thirty-five patients (52%) received cisplatin-based chemotherapy. The median follow-up of surviving patients was 42 months (12–118 months). Results: Five-year actuarial local control was 77%, regional control was 97%, progression-free survival was 56%, and overall survival was 58%. Stage was the only identifiable prognostic factor: 5-year progression-free survival was 65% for Stages I–III vs. 40% for Stage IV ( p = 0.01). The incidence of Grade 3–4 complications was 25% and included hearing loss, trismus, dysphagia, chronic sinusitis, and cranial neuropathy. These results are comparable to outcomes reported with conventional radiation techniques for similarly staged patients. Conclusion: The lack of a major benefit with the 3D boost may be related to the fact that CT planning was only used for a fraction of the total dose. We are now using intensity modulated radiation therapy to deliver the entire course of radiation. Intensity modulated radiation therapy achieves better conformal distributions than conventional 3D planning, allowing dose escalation and increased normal tissue sparing.
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treatment planning and delivery of intensity modulated radiation therapy for primary Nasopharynx Cancer
International Journal of Radiation Oncology Biology Physics, 2001Co-Authors: Margie Hunt, Suzanne L Wolden, Michael J Zelefsky, Chenshou Chui, Thomas Losasso, Kenneth E Rosenzweig, Lanceford M Chong, Spiridon V Spirou, Lisa Fromme, Moira LumleyAbstract:Purpose: To implement intensity-modulated radiation therapy (IMRT) for primary Nasopharynx Cancer and to compare this technique with conventional treatment methods. Methods and Materials: Between May 1998 and June 2000, 23 patients with primary Nasopharynx Cancer were treated with IMRT delivered with dynamic multileaf collimation. Treatments were designed using an inverse planning algorithm, which accepts dose and dose‐volume constraints for targets and normal structures. The IMRT plan was compared with a traditional plan consisting of phased lateral fields and a three-dimensional (3D) plan consisting of a combination of lateral fields and a 3D conformal plan. Results: Mean planning target volume (PTV) dose increased from 67.9 Gy with the traditional plan, to 74.6 Gy and 77.3 Gy with the 3D and IMRT plans, respectively. PTV coverage improved in the parapharyngeal region, the skull base, and the medial aspects of the nodal volumes using IMRT and doses to all normal structures decreased compared to the other treatment approaches. Average maximum cord dose decreased from 49 Gy with the traditional plan, to 44 Gy with the 3D plan and 34.5 Gy with IMRT. With the IMRT plan, the volume of mandible and temporal lobes receiving more than 60 Gy decreased by 10 ‐15% compared to the traditional and 3D plans. The mean parotid gland dose decreased with IMRT, although it was not low enough to preserve salivary function. Conclusion: Lower normal tissue doses and improved target coverage, primarily in the retropharynx, skull base, and nodal regions, were achieved using IMRT. IMRT could potentially improve locoregional control and toxicity at current dose levels or facilitate dose escalation to further enhance locoregional control. © 2001 Elsevier Science Inc.
A Pierelli - One of the best experts on this subject based on the ideXlab platform.
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intensity modulated proton therapy versus helical tomotherapy in Nasopharynx Cancer planning comparison and ntcp evaluation
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: L Widesott, C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, Nadia Di Muzio, Ferruccio Fazio, R Calandrino, Marco SchwarzAbstract:Purpose To compare intensity-modulated proton therapy (IMPT) and helical tomotherapy (HT) treatment plans for Nasopharynx Cancer using a simultaneous integrated boost approach. Methods and Materials The data from 6 patients who had previously been treated with HT were used. A three-beam IMPT technique was optimized in the Hyperion treatment planning system, simulating a “beam scanning” technique. HT was planned using the tomotherapy treatment planning system. Both techniques were optimized to simultaneously deliver 66 Gy in 30 fractions to planning target volume (PTV1; GTV and enlarged nodes) and 54 Gy to PTV2 subclinical, electively treated nodes. Normal tissue complication probability calculation was performed for the parotids and larynx. Results Very similar PTVs coverage and homogeneity of the target dose distribution for IMPT and HT were found. The conformity index was significantly lower for protons than for photons (1.19 vs. 1.42, respectively). The mean dose to the ipsilateral and contralateral parotid glands decreased by 6.4 Gy and 5.6 Gy, respectively, with IMPT. The volume of mucosa and esophagus receiving ≥20 Gy and ≥30 Gy with IMPT was significantly lower than with HT. The average volume of larynx receiving ≥50 Gy was significantly lower with HT, while for thyroid, it was comparable. The volume receiving ≥30, ≥20, and ≥10 Gy in total body volume decreased with IMPT by 14.5%, 19.4%, and 23.1%, respectively. The normal tissue complication probability for the parotid glands was significantly lower with IMPT for all sets of parameters; however, we also estimated an almost full recovery of the contralateral parotid with HT. The normal tissue complication probability for the larynx was not significantly different between the two irradiation techniques. Conclusion Excellent target coverage, homogeneity within the PTVs, and sparing of the organs at risk were reached with both modalities. IMPT allows for better sparing of most organs at risk at medium-to-low doses.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm3 [IMRT] to 18 cm3 [HT]); larynx (V30: 25 cm3 vs. 11 cm3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm3 vs. 1 cm3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy a planning study
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:PURPOSE: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. PATIENTS AND METHODS: Six T1-4 N1-3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. RESULTS: The fraction of PTV receiving >95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p<0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p<0.05). Significant gains (p<0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm(3) [IMRT] to 18 cm(3) [HT]); larynx (V30: 25 cm(3) vs. 11 cm(3)); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm(3) vs. 1 cm(3)); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). CONCLUSION: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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Simultaneous Integrated Boost (SIB) for Nasopharynx Cancer with Helical Tomotherapy
Strahlentherapie und Onkologie, 2007Co-Authors: C Fiorino, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, Italo Dell'oca, R CalandrinoAbstract:Purpose: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Patients and Methods: Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. Results: The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm^3 [IMRT] to 18 cm^3 [HT]); larynx (V30: 25 cm^3 vs. 11 cm^3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm^3 vs. 1 cm^3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). Conclusion: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT. Ziele: Untersuchung des Potentials der helikalen Tomotherapie (HT) beim Nasopharynxkarzinom. Patienten und Methodik: Sechs T1–4 N1–3-Patienten wurden einbezogen. Eine Technik des simultanen integrierten Boost (SIB) wurde geplant mit invers optimierter konventioneller intensitätsmodulierter Radiotherapie (IMRT; dynamischer Multileaf-Kollimator des Eclipse-Helios Varian-Systems) und mit HT. Die verschriebenen (medianen) Strahlungsdosen waren 54 Gy, 61,5 Gy und 64,5 Gy, die in 30 Fraktionen auf die Planungszielvolumina PTV1, PTV2 bzw. PTV3 gegeben wurden. Bei beiden Modalitäten, HT und IMRT, wurden für die PTV-Erfassung sowie für Parotiden, Rückenmark, Kiefer, optischen Apparat und Stammhirn dieselben Begrenzungen eingehalten. Der Planer versuchte auch, die Strahlungsdosis auf andere Regionen (Mukosa außerhalb von PTV1, Larynx, Ösophagus, Innenohr, Schilddrüse, Hirn, Lunge, Bindegewebe und Knochen unterhalb des Kinns) so stark wie möglich zu reduzieren. Ergebnisse: Der PTV-Anteil, der mehr als 95% der verschriebenen Strahlungsdosis (V95%) erhielt, erhöhte sich für PTV1 und PTV3 von 97,6% bzw. 94,3% (IMRT) auf 99,6% bzw. 97% (HT) (p < 0,05); die mediane Dosis der Parotiden verminderte sich von 30,1 Gy bei IMRT auf 25,0 Gy bei HT (p < 0,05). Signifikante Vorteile (p < 0,05) zeigten sich für die meisten Risikoorgane: Mukosa (V30-Verminderung von 44 cm^3 [IMRT] auf 18 cm^3 [HT]), Larynx (V30: 25 cm^3 vs. 11 cm^3), Schilddrüse (mittlere Strahlungsdosis: 48,7 Gy vs. 41,5 Gy), Ösophagus (V45: 4 cm^3 vs. 1 cm^3), Stammhirn (D1%: 45,1 Gy vs. 37,7 Gy). Schlussfolgerung: Verglichen mit der Linac-5-Felder-IMRT verbessert HT die Homogenität der Dosisverteilung innerhalb des PTV und die PTV-Erfassung bei signifkant besserer Schonung von Risikoorganen.
G M Cattaneo - One of the best experts on this subject based on the ideXlab platform.
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intensity modulated proton therapy versus helical tomotherapy in Nasopharynx Cancer planning comparison and ntcp evaluation
International Journal of Radiation Oncology Biology Physics, 2008Co-Authors: L Widesott, C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, Nadia Di Muzio, Ferruccio Fazio, R Calandrino, Marco SchwarzAbstract:Purpose To compare intensity-modulated proton therapy (IMPT) and helical tomotherapy (HT) treatment plans for Nasopharynx Cancer using a simultaneous integrated boost approach. Methods and Materials The data from 6 patients who had previously been treated with HT were used. A three-beam IMPT technique was optimized in the Hyperion treatment planning system, simulating a “beam scanning” technique. HT was planned using the tomotherapy treatment planning system. Both techniques were optimized to simultaneously deliver 66 Gy in 30 fractions to planning target volume (PTV1; GTV and enlarged nodes) and 54 Gy to PTV2 subclinical, electively treated nodes. Normal tissue complication probability calculation was performed for the parotids and larynx. Results Very similar PTVs coverage and homogeneity of the target dose distribution for IMPT and HT were found. The conformity index was significantly lower for protons than for photons (1.19 vs. 1.42, respectively). The mean dose to the ipsilateral and contralateral parotid glands decreased by 6.4 Gy and 5.6 Gy, respectively, with IMPT. The volume of mucosa and esophagus receiving ≥20 Gy and ≥30 Gy with IMPT was significantly lower than with HT. The average volume of larynx receiving ≥50 Gy was significantly lower with HT, while for thyroid, it was comparable. The volume receiving ≥30, ≥20, and ≥10 Gy in total body volume decreased with IMPT by 14.5%, 19.4%, and 23.1%, respectively. The normal tissue complication probability for the parotid glands was significantly lower with IMPT for all sets of parameters; however, we also estimated an almost full recovery of the contralateral parotid with HT. The normal tissue complication probability for the larynx was not significantly different between the two irradiation techniques. Conclusion Excellent target coverage, homogeneity within the PTVs, and sparing of the organs at risk were reached with both modalities. IMPT allows for better sparing of most organs at risk at medium-to-low doses.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm3 [IMRT] to 18 cm3 [HT]); larynx (V30: 25 cm3 vs. 11 cm3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm3 vs. 1 cm3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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simultaneous integrated boost sib for Nasopharynx Cancer with helical tomotherapy a planning study
Strahlentherapie Und Onkologie, 2007Co-Authors: C Fiorino, I Delloca, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, R CalandrinoAbstract:PURPOSE: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. PATIENTS AND METHODS: Six T1-4 N1-3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. RESULTS: The fraction of PTV receiving >95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p<0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p<0.05). Significant gains (p<0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm(3) [IMRT] to 18 cm(3) [HT]); larynx (V30: 25 cm(3) vs. 11 cm(3)); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm(3) vs. 1 cm(3)); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). CONCLUSION: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT.
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Simultaneous Integrated Boost (SIB) for Nasopharynx Cancer with Helical Tomotherapy
Strahlentherapie und Onkologie, 2007Co-Authors: C Fiorino, A Pierelli, S Broggi, G M Cattaneo, A Chiara, Elena De Martin, Nadia Di Muzio, Ferruccio Fazio, Italo Dell'oca, R CalandrinoAbstract:Purpose: To explore the potential of helical tomotherapy (HT) in the treatment of Nasopharynx Cancer. Patients and Methods: Six T1–4 N1–3 patients were considered. A simultaneous integrated boost (SIB) technique was planned with inversely optimized conventional intensity-modulated radiotherapy (IMRT; dynamic multileaf collimator using the Eclipse-Helios Varian system) and HT. The prescribed (median) doses were 54 Gy, 61.5 Gy, and 64.5 Gy delivered in 30 fractions to PTV1 (planning target volume), PTV2, and PTV3, respectively. The same constraints for PTV coverage and for parotids, spinal cord, mandible, optic structures, and brain stem were followed in both modalities. The planner also tried to reduce the dose to other structures (mucosae outside PTV1, larynx, esophagus, inner ear, thyroid, brain, lungs, submental connective tissue, bony structures) as much as possible. Results: The fraction of PTV receiving > 95% of the prescribed dose (V95%) increased from 97.6% and 94.3% (IMRT) to 99.6% and 97% (HT) for PTV1 and PTV3, respectively (p < 0.05); median dose to parotids decreased from 30.1 Gy for IMRT to 25.0 Gy for HT (p < 0.05). Significant gains (p < 0.05) were found for most organs at risk (OARs): mucosae (V30 decreased from 44 cm^3 [IMRT] to 18 cm^3 [HT]); larynx (V30: 25 cm^3 vs. 11 cm^3); thyroid (mean dose: 48.7 Gy vs. 41.5 Gy); esophagus (V45: 4 cm^3 vs. 1 cm^3); brain stem (D1%: 45.1 Gy vs. 37.7 Gy). Conclusion: HT improves the homogeneity of dose distribution within PTV and PTV coverage together with a significantly greater sparing of OARs compared to linac five-field IMRT. Ziele: Untersuchung des Potentials der helikalen Tomotherapie (HT) beim Nasopharynxkarzinom. Patienten und Methodik: Sechs T1–4 N1–3-Patienten wurden einbezogen. Eine Technik des simultanen integrierten Boost (SIB) wurde geplant mit invers optimierter konventioneller intensitätsmodulierter Radiotherapie (IMRT; dynamischer Multileaf-Kollimator des Eclipse-Helios Varian-Systems) und mit HT. Die verschriebenen (medianen) Strahlungsdosen waren 54 Gy, 61,5 Gy und 64,5 Gy, die in 30 Fraktionen auf die Planungszielvolumina PTV1, PTV2 bzw. PTV3 gegeben wurden. Bei beiden Modalitäten, HT und IMRT, wurden für die PTV-Erfassung sowie für Parotiden, Rückenmark, Kiefer, optischen Apparat und Stammhirn dieselben Begrenzungen eingehalten. Der Planer versuchte auch, die Strahlungsdosis auf andere Regionen (Mukosa außerhalb von PTV1, Larynx, Ösophagus, Innenohr, Schilddrüse, Hirn, Lunge, Bindegewebe und Knochen unterhalb des Kinns) so stark wie möglich zu reduzieren. Ergebnisse: Der PTV-Anteil, der mehr als 95% der verschriebenen Strahlungsdosis (V95%) erhielt, erhöhte sich für PTV1 und PTV3 von 97,6% bzw. 94,3% (IMRT) auf 99,6% bzw. 97% (HT) (p < 0,05); die mediane Dosis der Parotiden verminderte sich von 30,1 Gy bei IMRT auf 25,0 Gy bei HT (p < 0,05). Signifikante Vorteile (p < 0,05) zeigten sich für die meisten Risikoorgane: Mukosa (V30-Verminderung von 44 cm^3 [IMRT] auf 18 cm^3 [HT]), Larynx (V30: 25 cm^3 vs. 11 cm^3), Schilddrüse (mittlere Strahlungsdosis: 48,7 Gy vs. 41,5 Gy), Ösophagus (V45: 4 cm^3 vs. 1 cm^3), Stammhirn (D1%: 45,1 Gy vs. 37,7 Gy). Schlussfolgerung: Verglichen mit der Linac-5-Felder-IMRT verbessert HT die Homogenität der Dosisverteilung innerhalb des PTV und die PTV-Erfassung bei signifkant besserer Schonung von Risikoorganen.
