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Planning Target Volume (planning + target_volume)
Selected AbstractsPostoperative intensity-modulated radiation therapy for cancers of the paranasal sinuses, nasal cavity, and lacrimal glands: Technique, early outcomes, and toxicity,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 7 2008Bradford S. Hoppe MD Abstract Background Our aim was to review Memorial Sloan-Kettering Cancer Center's experience with postoperative intensity-modulated radiotherapy (IMRT) for paranasal sinus, nasal cavity, and lacrimal gland cancer and report dosimetric measures, toxicity, and outcomes. Methods Between September 2000 and June 2006, 37 patients with paranasal sinus, nasal cavity, or lacrimal gland cancer underwent postoperative IMRT. Median values were as follows: prescription dose, 60 Gy (range, 50,70); PTVD95, 99% (range, 79,101%); optic nerve Dmax, 53 Gy (range, 2,54); optic chiasm Dmax, 51Gy (range, 2,55). Acute and late toxicities were scored by Radiation Therapy Oncology Group morbidity criteria. Results Median follow-up was 28 months. Two-year local progression,free and overall survivals were 75% and 80%. No early- or late-grade 3/4 radiation-induced ophthalmologic toxicity occurred. Conclusions Preliminary results show that adjuvant IMRT in these patients is feasible, allowed for excellent planning target volume (PTV) coverage, and minimized dose delivered to optic structures. Longer follow-up is warranted to assess the extent of late effects and outcomes. © 2008 Wiley Periodicals, Inc. Head Neck, 2008 [source] Intensity-modulated radiotherapy with an integrated boost to the macroscopic tumor volume in the treatment of high-grade gliomasINTERNATIONAL JOURNAL OF CANCER, Issue 6 2001Christoph Thilmann M.D. Abstract Integrated boost radiotherapy (IBRT) delivers a higher fraction size to the gross tumor volume and a conventional fraction size to the surrounding tissue of microscopic spread. We compared stereotactic conformal radiotherapy (SCRT) and intensity-modulated radiotherapy (IMRT) with regard to their suitability for IBRT in the treatment of high-grade gliomas. In 20 patients treated with conventional radiotherapy, an additional treatment plan for IBRT [planning target volume (PTV1) defined as contrast-enhancing lesion plus margin due to setup errors 75 Gy, PTV2 defined as edema plus margin due to microscopic spread and setup error 60 Gy] with 7 non-coplanar beams for IMRT and for SCRT was carried out and compared. The part of the PTV2 irradiated with more than 107% of the prescribed dose was 13.9% for IMRT and 30.9% for SCRT (P < 0.001). Dose coverage of PTV2 (volume above 95% of the prescribed dose) was improved with IMRT (88.4% vs. 75.3% with SCRT, P < 0.001). Dose coverage of PTV1 was slightly higher with SCRT (93.7% vs. 87.5% with IMRT), but the conformity to the boost shape was improved by IMRT [conformity index (COIN95) = 0.85 vs. 0.69 with SCRT]. Simultaneously the brain volume irradiated with > 50 Gy was reduced from 60 to 33 cc (P < 0.001). We conclude that IMRT is suitable for local dose escalation in the enhancing lesion and for delivering a homogeneous dose to the PTV2 outside the PTV1 at the same time. Our encouraging results justify application of IMRT for IBRT in the treatment of high-grade gliomas. For clinical evaluation a phase III study has been initiated. © 2001 Wiley-Liss, Inc. [source] Improving bladder cancer treatment with radiotherapy using separate intensity modulated radiotherapy plans for boost and elective fieldsJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 3 2010DC Van Rooijen Summary The aim of this study is to investigate to what extent IMRT can decrease the dose to the organs at risk in bladder cancer treatment compared with conformal treatment while making separate treatment plans for the elective field and the boost. Special attention is paid to sparing small intestines. Twenty patients who were treated with the field-in-field technique (FiF) were re-planned with intensity modulated radiotherapy (IMRT) using five and seven beams, respectively. Separate treatment plans were made for the elective field (including the pelvic lymph nodes) and the boost, which enables position correction for bone and tumour separately. The prescribed dose was 40 Gy to the elective field and 55 or 60 Gy to the planning target volume (PTV). For bladder and rectum, V45Gy and V55Gy were compared, and for small intestines, V25Gy and V40Gy. The dose distribution with IMRT conformed better to the shape of the target. There was no significant difference between the techniques in dose to the healthy bladder. The median V40Gy of the small intestines decreased from 114 to 66 cc (P = 0.001) with five beam IMRT, and to 55 cc (P = 0.001) with seven beam IMRT compared with FiF. V45Gy for rectum decreased from 34.2% to 17.5% (P = 0.004) for both five and seven beam plans, while V55Gy for rectum remained the same. With IMRT, a statistically significant dose decrease to the small intestines can be achieved while covering both tumour and elective PTV adequately. [source] ,Boomerang' technique: An improved method for conformal treatment of locally advanced nasopharyngeal cancerJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 2 2004June Corry Summary The primary aim of the present study was to assess radiation dosimetry and subsequent clinical outcomes in patients with locally advanced nasopharyngeal cancer using a novel radiation technique termed the ,Boomerang'. Dosimetric comparisons were made with both conventional and intensity modulated radiation therapy (IMRT) techniques. This is a study of 22 patients treated with this technique from June 1995 to October 1998. The technique used entailed delivery of 36 Gy in 18 fractions via parallel opposed fields, then 24 Gy in 12 fractions via asymmetric rotating arc fields for a total of 60 Gy in 30 fractions. Patients also received induction and concurrent chemotherapy. The radiation dosimetry was excellent. Dose,volume histograms showed that with the arc fields, 90% of the planning target volume received 94% of the prescribed dose. Relative to other conventional radiation therapy off-cord techniques, the Boomerang technique results in a 27% greater proportion of the prescribed dose being received by 90% of the planning target volume. This translates into an overall 10% greater dose received for the same prescribed dose. At 3 years, the actuarial loco-regional control rate, the failure-free survival rate and the overall survival rate were 91, 75 and 91%, respectively. At 5 years, the actuarial loco-regional control rate, the failure-free survival rate and the overall survival rate were 74, 62 and 71%, respectively. The Boomerang technique provided excellent radiation dosimetry with correspondingly good loco-regional control rates (in conjunction with chemotherapy) and very acceptable acute and late toxicity profiles. Because treatment can be delivered with conventional standard treatment planning and delivery systems, it is a validated treatment option for centres that do not have the capability or capacity for IMRT. A derivative of the Boomerang technique, excluding the parallel opposed component, is now our standard for patients with locally advanced nasopharyngeal cancer when IMRT is not available. [source] Accrediting radiation technique in a multicentre trial of chemoradiation for pancreatic cancerJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 6 2008N Spry Summary Before a multicentre trial of 3-D conformal radiotherapy to treat cancer of the pancreas, participating clinicians were asked to complete an accreditation exercise. This involved planning two test cases according to the study protocol, then returning hard copies of the plans and dosimetric data for review. Any radiation technique that achieved the specified constraints was allowed. Eighteen treatment plans were assessed. Seven plans were prescribed incorrect doses and two of the planning target volumes did not comply with protocol guidelines. All plans met predefined normal tissue dose constraints. The identified errors were attributable to unforeseen ambiguities in protocol documentation. They were addressed by feedback and corresponding amendments to protocol documentation. Summary radiobiological measures including total weighted normal tissue equivalent uniform dose varied significantly between centres. This accreditation exercise successfully identified significant potential sources of protocol violations, which were then easily corrected. We believe that this process should be applied to all clinical trials involving radiotherapy. Due to the limitations of data analysis with hard-copy information only, it is recommended that complete planning datasets from treatment-planning systems be collected through a digital submission process. [source] | ||||||||||