Dosimetric integration of daily mega-voltage cone-beam CT for image-guided intensity-modulated radiotherapy.

PURPOSE: The goal of this work was to compare different methods of incorporating the additional dose of mega-voltage cone-beam CT (MV-CBCT) for image-guided intensity modulated radiotherapy (IMRT) of different tumor entities. MATERIAL AND METHODS: The absolute dose delivered by the MV-CBCT was calculated and considered by creating a scaled IMRT plan (scIMRT) by renormalizing the clinically approved plan (orgIMRT) so that the sum with the MV-CBCT dose yields the same prescribed dose. In the other case, a newly optimized plan (optIMRT) was generated by including the dose distribution of the MV-CBCT as pre-irradiation. Both plans were compared with the orgIMRT plan and a plan where the last fraction was skipped. RESULTS: No significant changes were observed regarding the 95% conformity index of the target volume. The mean dose of the organs at risk (OAR) increased by approx. 7% for the scIMRT plan and 5% for the optIMRT plan. A significant increase of the mean dose to the outline contour was observed, ranging from 3.1 ± 1.3% (optIMRT) to 13.0 ± 6.1% (scIMRT) for both methods over all entities. If the dose of daily MV-CBCT would have been ignored, the additional dose accumulated to nearly a whole treatment fraction with a general increase of approx. 10% to the OARs and approx. 4% to the target volume. CONCLUSION: Both methods of incorporating the additional MV-CBCT dose into the treatment plan are suitable for clinical practice. The dose distribution of the target volume could be achieved as conformal as with the orgIMRT plan, while only a moderate increase of mean dose to OAR was observed.

[Evaluation of time, attendance of medical staff, and resources during stereotactic radiotherapy/radiosurgery : QUIRO-DEGRO Trial].

BACKGROUND: The German Society of Radiation Oncology ("Deutsche Gesellschaft für Radioonkologie", DEGRO) initiated a multicenter trial to develop and evaluate adequate modules to assert core processes and subprocesses in radiotherapy. The aim of this prospective evaluation was to methodical assess the required resources (technical equipment and medical staff) for stereotactic radiotherapy/radiosurgery. MATERIAL AND METHODS: At two radiotherapy centers of excellence (University Hospitals of Heidelberg and Marburg/Giessen), the manpower and time required for the implementation of intra- and extracranial stereotactic radiotherapy was prospectively collected consistently over a 3-month period. The data were collected using specifically developed process acquisition tools and standard forms and were evaluated using specific process analysis tools. RESULTS: For intracranial (extracranial) fractionated stereotactic radiotherapy (FSRT) and radiosurgery (RS), a total of 1,925 (270) and 199 (36) records, respectively, could be evaluated. The approximate time needed to customize the immobilization device was median 37 min (89 min) for FRST and 31 min (26 min) for RS, for the contrast enhanced planning studies 22 and 27 min (25 and 28 min), for physical treatment planning 122 and 59 min (187 and 27 min), for the first and routine radiotherapy sessions for FSRT 40 and 13 min (58 and 31 min), respectively. The median time needed for the RS session was 58 min (45 min). The corresponding minimal manpower needed was 2 technicians for customization of the immobilization device, 2.5 technicians and 1 consultant for the contrast-enhanced planning studies, 1 consultant, 0.5 resident and 0.67 medical physics expert (MPE) for physical treatment planning, as well as 1 consultant, 0.5 resident, and 2.5 technicians for the first radiotherapy treatment and 2.33 technicians for routine radiotherapy sessions. CONCLUSION: For the first time, the resource requirements for a radiotherapy department for the maintenance, protection and optimization of operational readiness for the application of intra- and extracranial stereotactic radiotherapy was determined methodically.

Fractionated stereotactically guided radiotherapy and radiosurgery in the treatment of functional and nonfunctional adenomas of the pituitary gland.

PURPOSE: We evaluated survival rates and side effects after fractionated stereotactically guided radiotherapy (SCRT) and radiosurgery in patients with pituitary adenoma. METHODS AND MATERIALS: Between 1989 and 1998, 68 patients were treated with FSRT (n = 63) or radiosurgery (n = 5) for pituitary adenomas. Twenty-six had functional and 42 had nonfunctional adenomas. Follow-up included CT/MRI, endocrinologic, and ophthalmologic examinations. Mean follow-up was 38.7 months. Seven patients received radiotherapy as primary treatment and 39 patients received it postoperatively for residual disease. Twenty-two patients were treated for recurrent disease after surgery. Mean total dose was 52.2 Gy for SCRT, and 15 Gy for radiosurgery. RESULTS: Overall local tumor control was 93% (60/65 patients). Forty-three patients had stable disease based on CT/MRI, while 15 had a reduction of tumor volume. After FSRT, 26% with a functional adenoma had a complete remission and 19% had a reduction of hormonal overproduction after 34 months' mean. Two patients with STH-secreting adenomas had an endocrinologic recurrence, one with an ACTH-secreting adenoma radiologic recurrence, within 54 months. Reduction of visual acuity was seen in 4 patients and partial hypopituitarism in 3 patients. None of the patients developed brain radionecrosis or radiation-induced gliomas. CONCLUSION: Stereotactically guided radiotherapy is effective and safe in the treatment of pituitary adenomas to improve local control and reduce hormonal overproduction.

Calcification in coronary arteries as quantified by CT scans correlated with tobacco consumption in patients with inoperable non-small cell lung cancer treated with three-dimensional radiotherapy.

It has been shown that radiological manifestations of coronary artery sclerosis are an indirect measure of co-morbidity and predictive of survival. The aim of the present study is to evaluate the outcome and side effects after three-dimensional (3D) radiotherapy in patients with unresectable non-small cell lung cancer (NSCLC) stage I, II and IIIA, depending on coronary artery calcification, Karnofsky performance index (KI) and co-morbidity. Between 1993 and 1999, 89 patients with unresectable NSCLC were treated with 3D-radiotherapy. The median age was 66.6 years and median KI 80%. All patients had 3D-treatment planning, based on CT scans. The median total dose was 60 Gy in 2 Gy fractions five times a week. The mean follow-up period was 13.2 months and mean survival time 12.2 months. Significant prognostic factors for improved survival were KI and tumour stage. Patients with a KI<90% had a median survival of 6.5 months compared with 14 months, in patients with KI>/==" BORDER="0">90% (p<0.001). NSCLC stage I+II showed a significantly longer median survival than patients with NSCLC stage IIIA (16.5 months versus 7 months, p<0.004). A significant correlation was seen between pack-years and coronary artery calcification (p<0.05) and between age and marked coronary artery calcification. The incidence of calcification was 67% in smokers (>/==" BORDER="0">20 pack-years) and 43/58 in patients >60 years (p<0.007). Side effects, e.g. pneumonitis, did not correlate with coronary artery calcification but correlated with chronic obstructive lung disease in 19/89 patients. Conventional CT scans for 3D-treatment planning are able to detect coronary artery calcification. There is a significant correlation between age, KI, tobacco consumption and vascular calcification. Although there was a trend to worse overall survival, coronary artery calcification was not a significant predictor of progression-free and overall survival.

[Postoperative radiotherapy of the chest wall in patients with male breast cancer]. / Postoperative Strahlentherapie der Thoraxwand beim Mammakarzinom des Mannes.

INTRODUCTION: We analysed our long-term results with postoperative radiotherapy of the chest wall in male breast cancer patients with respect to local control and survival. METHODS: Twenty-five patients with 26 histological proven carcinomas of the male breast underwent postoperative radiotherapy of the chest wall with (n = 15) or without regional lymphatics after mastectomy. Additionally 13 patients received adjuvant hormones and 3 patients adjuvant chemotherapy. Median age at treatment was 62.2 years (45.9-78.5 years). Median follow-up was 15.3 years (7.7-27.5 years). RESULTS: Overall survival after radiotherapy was 28 %, disease-specific survival was 64 %. Actuarial 3-, 5- and 10-year survival was 72 %, 56 % and 35 %. Median survival time was 6.1 years. Actuarial progression-free survival was 80 %, 52 % and 43 % after 3, 5 and 10 years, respectively. Local tumor control was 92 % (24 / 26). Survival was significantly affected by the presence of lymph node metastases (p < 0.01) and localisation of the tumor in the right breast (p < 0.04). CONCLUSION: Postoperative radiotherapy is an important part of the management of male breast cancer to improve local control and progression-free survival. The presence of lymph node metastases significantly impairs survival.

Multicompartment analysis of gadolinium chelate kinetics: blood-tissue exchange in mammary tumors as monitored by dynamic MR imaging.

The blood-tissue exchange kinetics of gadopentetate were studied in 49 malignant and benign mammary tumors. Signal enhancement was monitored simultaneously in the aorta and in tumor for 10.5 minutes after the beginning of a 1 minute i.v. infusion of the contrast medium (CM). Kinetic analysis was based on a model with two compartments for systemic pharmacokinetics and up to three kinetically distinct compartments for tumor. Kinetic heterogeneity, ie, two or more compartments with different exchange rate constants in a given tumor, was found in 85% of carcinomas, 38% of fibroadenomas, and 14% of mastopathic tumors. The within-tumor average of CM exchange rates was 1.22 (0.62-1.65) min(-1) in carcinomas, 0.38 (0.26-0.60) min(-1) in fibroadenomas, and 0.16 (0. 12-0.20) min(-1) in mastopathies (median and interquartile distances). The area under the signal enhancement-time curve of the aorta varied 4.5-fold between individuals. It is concluded that individual CM kinetics in arterial blood should be taken into account when CM exchange rates between blood and tumor are to be determined and that a kinetic model for potentially malignant tumors should allow for kinetic heterogeneity.