Objective: Gamma knife and multileaf collimator LINAC have recently gained notority in the treatment of vestibular schwannomas. Without the use of gamma knife or LINAC, we have successfully pursued the 125-iodine interstitial irradiation of three vestibular schwannomas.Case Report: Up to March 2004, there was a 57 and 45 month follow-up period in two cases. One patient died of heart insufficiency 15 months after the brachytherapy. At the end of the follow-up period audiometric examinations revealed slight improvements of hearing in patients 1 and 2. In patient 1, the tumor volume measured was 4.06 mL on the control CT indicating a 40% shrinkage in comparison to the 6.74 mL target volume at the brachytherapy. In patient 2, the tumor volume measured on the control MRI was 6.64 mL, indicating a 42% shrinkage of the 11.45 mL target volume at the time of brachytherapy. Eleven months after the brachytherapy in patient 3 we found 10% tumor shrinkage, a post-irradiation cyst developed inside the tumor and reached up to 35% of the tumor volume.Intervention: In the treatment of three vestibular schwannomas we have used CT and image-fusion guided 125-iodine stereotactic brachytherapy.Conclusion: Due to financial considerations, gamma knife and LINAC are not available for many countries and neurosurgical institutes. In the absence of the above-mentioned radiosurgical methods, we have shown brachytherapy as a new alternative and solution in the treatment of the three patients studied with vestibular schwannoma.

Purpose: To report the 7-year results of a prospective study of accelerated partial breast irradiation (APBI) using interstitial high-dose-rate brachytherapy and compare the treatment results with those achieved by standard, whole breast radiotherapy (WBRT), with or without a tumor bed boost (TBB).Methods and Materials: Between 1996 and 1998, 45 prospectively selected patients with T1N0-N1mi (single nodal micrometastasis), nonlobular breast cancer without the presence of an extensive intraductal component and with negative surgical margins were treated with APBI using interstitial high-dose-rate implants. A total dose of 30.3 Gy (n = 8) and 36.4 Gy (n = 37) in seven fractions within 4 days was delivered to the tumor bed plus a 1-2-cm margin. During the same period, 80 patients, who met the eligibility criteria for APBI but who were treated with 50 Gy WBRT with (n = 36) or without (n = 44) a 10-16-Gy TBB, were selected as controls. The median follow-up for the APBI and control groups was 81 and 83 months, respectively. Local control, relapse-free survival, cancer-specific survival, late side effects, and cosmetic results were assessed.Results: The crude rate of total ipsilateral breast failure was 6.7% (3 of 45), 11.4% (5 of 44), and 8.3% (3 of 36) for patients treated with APBI, WBRT, and WBRT + TBB, respectively. The differences in the 5- and 7-year actuarial rates of ipsilateral breast recurrence were not statistically significant among patients treated with APBI (4.4% and 9.0%), WBRT (4.7% and 14.8%), and WBRT + TBB (5.7% and 9.5%). No statistically significant difference in either the 7-year probability of relapse-free survival (79.8%, 73.5%, and 77.7% for APBI, WBRT, and WBRT + TBB, respectively) or cancer-specific survival (93.3%, 92.9%, and 93.9% for APBI, WBRT, and WBRT + TBB, respectively) was found. The 7-year actuarial elsewhere breast failure rate was 9.0% in the APBI group and 8.3% in the control group (p = 0.80). The rate of excellent/good cosmetic results was 84.4% in the APBI group and 68.3% in the control group (p = 0.04). The corresponding rates of asymptomatic fat necrosis were 20.0% and 20.6%. Symptomatic fat necrosis occurred in 1 patient (2.2%) treated with APBI. The incidence of Grade 2 or worse late radiation side effects was similar for both groups (26.7% vs. 28.6%).Conclusion: Accelerated partial breast irradiation using interstitial high-dose-rate implants, with proper patient selection and quality assurance, yields similar 7-year results to those achieved with standard breast-conserving therapy. APBI does not increase the risk of elsewhere breast failures. (C) 2004 Elsevier Inc.

The use of a stepping source in high dose rate brachytherapy supported with dwell-time optimization makes it possible to deviate from the classical dosimetry systems. Dose distributions of single- and double-plane implants were analysed for conformality and homogeneity at idealized target volumes. The Paris system was used for catheter positioning and target volume determination. Geometric optimization and individual dose prescription were applied. Volumetric indices and dose parameters were calculated at optimal active length, which was found to be equal to target volume length. The mean conformality, homogeneity, external volume and overdose volume indices were 0.78, 0.67, 0.22 and 0.13, respectively. The average minimum target and reference doses were 69% and 86%, respectively. Comparisons between the volumetric indices of geometrical optimized and non-optimized implants were also performed, and a significant difference was found regarding any index. The geometrical optimization resulted in superior conformality and slightly inferior homogeneity. At geometrically optimized implants, the active length can be reduced compared to non-optimized implants. Volumetric parameters and dose-volume histogram-based individual dose prescription are recommended for quantitative assessment of interstitial implants.

To explore pathways of the energy transition of household heating, an agent-based simulation model was developed for the case of the Serbian household sector. The model is focused on individual entities (households) with the objective to explore the effects of policy instruments on energy transition in households with individual heating systems. Empirically collected survey data were used as input for households' attitudes towards sustainable heating. Simulations showed that the proposed instruments would lead to higher heating efficiency and less air pollution, and impact climate change. However, despite the introduced instruments, a proportion of households (around 11%) will not switch current obsolete firewood-based heating to more efficient heating in the observed period. The main reasons for this phenomenon are a low economic standard, accompanied by ignorance on the part of the population regarding the environmental and climate effects of outdated technologies. Sensitivity analysis was conducted to investigate the effects of different heating system prices, energy prices, and efficiencies, on the transition towards sustainable heating. It was shown that the introduction of a carbon electricity tax would cause a slight increase in the use of firewood and fossil fuels, while local pollution taxation would be an impulse for the use of electricity for heating. The increased energy efficiency of buildings is stimulative for more efficient heating systems. Mass utilization of heat pump technology and renewable energy sources could be expected with obtained maturity in technologies and consequently, the reduction of their prices.

In our prospective study we examined the use of low-dose paclitaxel concurrently with radiation for patients with locally advanced head and neck cancer, who were not eligible for concurrent chemoradiation due to their poor general condition. Twenty-six patients were treated with external beam radiotherapy and received concomitantly 2 mg/m(2) paclitaxel three times a week. Beside an acceptable efficacy (RR: 65%, 2-year overall survival 46%) the treatment was well tolerated and resulted in a favorable toxicity profile. This regimen is resource effective and allowed successive therapy if it was necessary and therefore may serve as an alternative for patients in poor condition with locally advanced head and neck cancer.

Background and purpose: The use of high dose rate stepping source in interstitial brachytherapy provides more possibility to conform the dose distribution to the target volume compared to the classical systems. The purpose of this study was to evaluate implants made according to the Paris, the stepping source and the conformal dosimetry system with respect to dose homogeneity and conformality, and to compare these systems using volumetric parameters.Materials and methods: Single-plane and double-plane implants with catheters arranged in square and triangle pattern were used in the analysis. Twenty-seven idealized planning target volumes (PTV) were generated. They formed slabs with rectangular or trapezoidal cross-section. The lengths were 3, 5 and 7 cm, the widths and heights were determined according to the Paris system for catheter separation of 1, 1.5 and 2 cm. The dose specification was selected such that the coverage index was 0.95 for each implant. Optimal active lengths were determined according to the best conformality at the optimized implants. From the dose-volume histogram (DVH) the following indices were calculated for every implant: conformal (COIN), external volume (EI), relative dose homogeneity (HI) and overdose volume (01). Furthermore, the mean central dose (MCD) and minimum target dose (MTD) was also determined. The dosimetry systems were compared through the mean values of these parameters and the volumetric indices were analyzed according to the geometry of the PTV.Results: For the optimized systems the optimal active length was 0.5-1.0 cm shorter than the target volume length, depending on the catheter separation and geometry of the PTV. For the Paris, the stepping source and the conformal dosimetry system, the mean COIN was 0.66, 0.82 and 0.82; the mean HI was 0.71, 0.68 and 0.68; the mean EI was 0.44, 0.17 and 0.17; the mean OI was 0.11, 0.13 and 0.12, respectively. The statistical analysis showed that the Paris system differed from the optimized systems significantly. For the Paris, the stepping source and the conformal dosimetry system, the mean reference isodose was 85, 90 and 95%, the MCD was 100, 100 and 109% the MTD was 67, 71 and 73%, respectively. Regarding geometry of the PTV, the most conformal and homogeneous dose distributions occurred when the catheter separation was small, the target volume was long and its shape was a thick rectangular slab.Conclusions: Positioning the catheters according to the rules of the Paris system, but applying optimization on dose points placed either between the catheters in the whole target volume or on the surface of the target volume, and selecting the reference isodose by DVH, can provide highly conformal dose distribution to the target volume, with only a slightly worsened dose homogeneity compared to the Paris system. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Purpose/Objective: To test the feasibility of sole interstitial high-dose-rate brachytherapy (HDR-BT) after breast conserving surgery (BCS) for T1 breast cancer in a phase I-II study, and to present the initial findings of a phase III trial comparing the efficacy of tumor bed irradiation (TBRT) alone with conventional whole breast radiotherapy (WBRT). Materials/Methods: Forty-five prospectively selected patients with T1 N0-1a breast cancer undergoing BCS were enrolled into a phase I-II study of TBRT alone, using interstitial HDR implants. HDR-BT of 7 × 4.33 Gy (n = 8) and 7 × 5.2 Gy (n = 37) was delivered to the tumor bed. Based on the results of this phase I-II study, a further 181 patients were randomized to receive 50 Gy WBRT (n = 92) or TBRT alone (n = 89); the latter consisted of either 7 × 5.2 Gy HDR-BT (n = 64) or 50 Gy wide field electron irradiation (n = 25). Breast cancer related events and side effects were assessed. Results: 1. Phase I-II study: At a median follow-up of 60 months 2 (4.4%) local, 3 (6.7%) axillary, and 3 (6.7%) distant failures were observed. Two patients (4.4%) died of breast cancer. The 5-year probability of cancer-specific (CSS), relapse-free (RFS) and local recurrence-free survival (LRFS) was 90.0%, 85.9% and 95.6%, respectively. The cosmetic results were judged to be excellent in 44 out of 45 patients (97.8%). Severe (> G 2) skin sequale or fibrosis was not found. Symptomatic fat necrosis occured in 1 (2.2%) patient. 2. Phase III study: At a median follow-up of 30 months, 1 patient (1.1%) in TBRT arm developed local recurrence. The 3-year probability of CSS, RFS and LRFS was 98.1%, 98.4% and 100% in the WBRT group and 100%, 93.6% and 98.2% in the TBRT group, respectively (p = NS). There was no significant difference between the two treatment arms regarding the incidence of radiation side effects. Conclusions: Five-year results of our phase I-II study prove that sole HDR-BT of the tumor bed with careful patient selection and adequate quality assurance is a feasible alternative to WBRT. At a median follow-up of 30 months in phase III study, HDR-BT alone is similar to WBRT with respect to skin and parenchymal side effects. Longer follow-up is required to draw a final conclusion regarding the difference in local control rate between the two treatment arms. Promising early results of our randomized study support further accrual in this ongoing trial without protocol amendment.

We have examined time intervals between events in 390 metastatic breast cancer (MBC) patients whose distant failure developed within 10 years from initial surgery of Stage I/II disease. All of the patients underwent axillary dissection and mastectomy (n=295) or breast-conserving surgery (BCS, n=95), between 1983 and 1987. Distinctions have been made between distant failure with (n=79) and without (n=311) isolated local-regional recurrence (LRR). The median survival time after first relapse was significantly longer with intrabreast (30 months) and chest wall (24 months) than with distant relapse (15 months), but with axillary (17 months) or with supraclavicular (17 months) relapse survival was similar. The delay between LRR and distant metastasis was shorter with axillary (7 months) and supraclavicular (9 months) than with breast (20 months) and chest wall (12 months) recurrences. The median postmetastatic survival time by site of first relapse was significantly shorter with supraclavicular (6 months) and axillary (9 months) than with distant site relapse (15 months) but with intrabreast (12 months) or with chest wall (11 months) recurrence survival was similar. In MBC, regional recurrences are associated with a shorter interval between events than with local recurrences. The shortened intervals for patients with regional recurrence suggest that metastases existed at the time of initial surgery. The question of whether prevention of local or regional recurrence or both improves cause-specific survival after mastectomy or BCS needs to be answered in randomized studies.

In this report, a unique case of a localized (T1N0M0) adenocarcinoma of the head of the pancreas is presented, which was successfully treated with interstitial high dose rate brachytherapy combined with percutan irradiation after biopsy. A total dose of 18 Gy was delivered with brachytherapy (6 Gy per fraction on three consecutive days) to the tumor via after-loading catheter. Brachytherapy was followed by external radiotherapy, delivering an additional dose of 46 Gy (18 MV-x) with four-field technique using conventional fractionation (2 Gy/day). Thirty-six months after completion of the treatment the patient is alive with no evidence of disease. The combination of interstitial high dose rate brachytherapy and external beam radiation therapy may be an effective tool to deliver curative dose without any significant sequelae in the treatment of operable pancreatic carcinoma, when the patient's condition contraindicates surgery.

The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7 - 17.1 and 40.4 - 16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7 - 4.8 ccm for 3D-HOF and 10.7 - 12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma.

The purpose of the study was to examine if the CT densitometric analysis during radiotherapy (RT) of brain tumors is suitable for the early detection of RT induced brain edema (BE), predicting related neurological progress, and assessing the effects of different edema therapies. Planimetric CT-densitograms were constructed by modifying the "High-Lighting" method. Three theoretical density regions were defined and color-coded on the images of the brain. These were defined as edema (10-20 HU), mild edema, and normal brain (29-38 HU). Corresponding axial CT slices were created at the mid-level of the lesion and that of the periventricular white matter to verify the changes in perifocal and diffuse BE. The monitoring was performed on 50 solitary brain tumor patients treated with RT. During RT courses weekly CT-densitometric examinations were carried out. We experienced that changes in densitograms coincided with clinical symptoms, furthermore, preceded the latter. With the use of preventive edema medication based on diuretics and along with adjunctive edema medication adopted to densitograms, the 5-7 week irradiation was completed without ultimate worsening in performance state in 49 of 50 cases and besides we succeeded in avoiding the routine usage of steroids. Based on our findings the CT-densitometry is suitable for early detection and continuous assessment of BE and preventing patient distress during RT. This simple, reproducible and non-invasive procedure could provide an additional clinical tool for new treatment strategies.