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Biomedical subjects

G Storme

Publications and source records attributed to G Storme.

At least 19 recordsLinked to original sources
PubMed2006

Optimal control of set-up margins and internal margins for intra- and extracranial radiotherapy using stereoscopic kilovoltage imaging.

In this paper the clinical introduction of stereoscopic kV-imaging in combination with a 6 degrees-of-freedom (6 DOF) robotics system and breathing synchronized irradiation will be discussed in view of optimally reducing interfractional as well as intrafractional geometric uncertainties in conformal radiation therapy. Extracranial cases represent approximately 70% of the patient population on the NOVALIS treatment machine (BrainLAB A.G., Germany) at the AZ-VUB, which is largely due to the efficiency of the real-time positioning features of the kV-imaging system. The prostate case will be used as an example of those target volumes showing considerable changes in position from day-to-day, yet with negligible motion during the actual course of the treatment. As such it will be used to illustrate the on-line target localization using kV-imaging and 6 DOF patient adjustment with and without implanted radio-opaque markers prior to treatment. Small lung lesion will be used to illustrate the system's potential to synchronize the irradiation with breathing in coping with intrafractional organ motion.

Brain Neoplasms↗
PubMed2006

No nodal cutoff in node-positive breast cancer women treated with mastectomy.

PURPOSE: To search for a prognostic cutoff in the number of involved axillary lymph-nodes, in T1-T2 node-positive (N+) breast cancer treated with mastectomy without radiotherapy. MATERIALS AND METHODS: Women aged 51-64 years presenting with a first primary T1-T2, N+, M0 unilateral carcinoma diagnosed in 1988-97 were selected from the SEER 9-registries. Cutoffs from 1 to 23 nodes were scanned with Cox models that included diagnostic year, age, area, race, marital status, histology, grade, hormone receptors, tumor location, size, and nodes examined. Outcomes were breast cancer specific and any-cause death. RESULTS: The overall mortality hazard ratio of a higher number of involved nodes as compared with a lower number ranged from 1.78 [95% confidence 1.58-1.99] with 1-node cutoff, to 3.65 [2.52-5.29] with 23-nodes cutoff. Breast cancer specific mortality hazard ratio ranged from 1.99 [1.73-2.29] with 1-node cutoff, to 4.63 [3.11-6.91] with 23-nodes cutoff. The graph of the hazard ratios showed a continuously increasing risk of overall and breast cancer specific mortality, without any identifiable cutpoint change. CONCLUSION: The results show no prognostic cutoff in the number of involved axillary lymph nodes in patients who did not receive radiotherapy. The rationale of nodal cutoff as an indicator for post-mastectomy adjuvant treatment in node-positive patients should be questioned.

Breast Neoplasms↗
PubMed2002

Acute toxicity of conventional radiation therapy for high-risk prostate cancer in EORTC trial 22863.

OBJECTIVES: We analysed the acute toxicity observed in the European Organisation for Research and Treatment of Cancer (EORTC) randomised trial 22863 comparing conventional external irradiation with or without an agonist analogue of gonadotropin-releasing hormone in high-risk prostate cancer patients. METHODS: Four hundred five patients that received a dose of at least 30 Gy were considered evaluable for acute toxicity assessment. Toxicity was grouped in a few categories: general, genito-urinary, and lower gastro-intestinal. Univariate and multivariate analyses were performed using the World Health Organisation (WHO) toxicity score and grouping together toxicity scores in different bimodal and trimodal groups. RESULTS: Overall, our data show that age, previous surgery and irradiation dose are important predictive factors for acute toxicity, but not the use of combined hormone therapy. Fifteen percent of patients suffered of moderate to severe acute toxicity (WHO G3-G4). Life threatening toxicity was observed in six cases (1.5%). CONCLUSIONS: The assessment of toxicity combining in different groups the original five scores scale produced conflicting results similar to those commonly reported in literature. Interpretation of the role of pre-treatment factors with uneven distribution in the study requires careful evaluation. These data obtained with conventional curative irradiation of high-risk prostate cancer patients are proposed for comparison with results achieved using modern state-of-the-art irradiation techniques.

Adult↗
PubMed2001

Remote control for a stand-alone freely movable treatment couch with limitation system.

One of our linear accelerators is equipped with a free-movable treatment couch. An additional projects was to develop a system that first protects the free-movable couch against collisions, secondly build a remote control for moving the couch from outside the treatment room and finally implement this remote control/limitation system in an automatic position algorithm using an electronic portal image. The latter has been the subject of an on-going departmental investigation on intra-fractional correction of set-up errors. A few years ago, we developed a limitation system to protect both the table and the accelerator against collisions. In this paper we describe the second part of this project, the remote control system.

Algorithms↗
PubMed2001

Attitudes and knowledge about cancer pain in Flanders. The educational effect of workshops regarding pain and symptom control.

Despite international agreements and recommendations regarding cancer pain therapy, the effectiveness of pain treatment is still a major problem even in Western countries. Part of the problem is that physicians and nurses often lack knowledge of methods for the assessment and treatment of cancer pain and may have many rigid beliefs and attitudes. This study investigated the misconceptions of physicians and nurses that play a role in the undertreatment of pain in Flanders (Belgium). We approached 197 health care workers who participated in the pain and symptom control education sessions organized by the Federation Palliative Care Flanders, and asked them to complete a questionnaire both before and after the sessions. The impact of the education sessions on their knowledge and beliefs regarding the management of cancer pain was substantial. Methods of reaching the target groups that do not feel the need for further education are discussed.

Analgesics, Opioid↗
PubMed2000

Adjuvant radiotherapy for breast cancer significantly improves overall survival: the missing link.

BACKGROUND AND PURPOSE: The influence of surgical adjuvant radiotherapy on overall survival of patients with operable breast cancer is still a controversial subject. The negative result of the EBCTCG meta-analysis (Early breast cancer trialists', collaborative group. Effects of radiotherapy and surgery in early breast cancer. An overview of the randomised trials. N. Engl. J. Med. 1995;333:1444-1455) of clinical randomized trials on adjuvant radiotherapy in breast cancer is in strong contrast with the Danish 82B, 82C and British Columbia trials (Overgaard M, Hanse PS, Overgaar J, et al. Postoperative radiotherapy in high-risk premenopausal women with breast cancer who receive adjuvant chemotherapy. Danish Breast Cancer Cooperative Group 82b Trial. N. Engl. J. Med. 1997;337:949-955; Overgaard M, Jensen MB, Overgaard J, et al. Postoperative radiotherapy in high-risk postmenopausal breast-cancer patients given adjuvant tamoxifen: Danish Breast Cancer Cooperative Group DBCG 82c randomized trial. Lancet 1999;353:1641-1648; Ragaz J, Jackson S, Le N, et al. Adjuvant radiotherapy and chemotherapy in node-positive premenopausal women with breast cancer. N. Engl. J. Med. 1997;337:956-962) showing an impressive survival benefit. This paper tries to fill in the gap between the conflicting results. MATERIALS AND METHODS: The 36 trials of the EBCTCG (Early breast cancer trialists', collaborative group, 1995) were prospectively screened for a number of objective parameters that are usually not analyzed in review papers. The odds of death data (and its variance) were borrowed from the original meta-analysis (Early breast cancer trialists', collaborative group, 1995) to check whether the objective features were significant predictors for overall survival benefit. RESULTS: A significant survival benefit for the radiotherapy arm was found for recent trials (2P<0.05), large trials (2P<0.03), trials that used standard fractionation (2P<0.02), and trials with a favourable crude survival (2P<0.03). For these four parameters clear parameter-effect relations were found. In recent and large trials the odds reduction was 12.4% (2P=0.004). CONCLUSIONS: Surgical adjuvant radiotherapy significantly improves overall survival of breast cancer patients provided that current techniques are used and treatment is given with standard fractionation. For the best subgroups we observed an odds of death reduction of more than 20%. The results of this study stress the importance of reducing cardiovascular and other late toxicity in adjuvant radiotherapy for breast cancer.

Breast Neoplasms↗
PubMed2000

Late and localized extramedullary relapse of a light chain kappa myeloma after syngeneic bone marrow transplantation.

We report the case of a 54-year-old female patient with stage IIIA kappa light chain myeloma (MM) who relapsed 7 years after syngeneic bone marrow transplantation (BMT). The relapse occurred as a voluminous soft tissue plasmacytoma in the leg, developing after local trauma. The patient was successfully treated with local radiotherapy and has remained progression-free for more than 2 years. This case represents one of the longest survivors, in complete remission, after syngeneic transplantation for MM. The presentation of recurrent disease as localized plasmacytoma with extramedullary growth is unusual in the post-transplant setting. Bone Marrow Transplantation (2000) 25, 115-117.

Bone Marrow Transplantation↗
PubMed2000

The effect of timing of the provision of information on anxiety and satisfaction of cancer patients receiving radiotherapy.

BACKGROUND: To improve the provision of information to their radiotherapy patients, the authors examined whether the timing of given written information has an effect on anxiety and satisfaction. METHODS: Two sources of information were used: 1) a booklet with a description of radiotherapy procedures and the sensations patients can experience; 2) teaching sheets with treatment-site-related information. 68 patients were randomized to a simultaneous-information group (n = 31) and a stepwise-information group (n = 37). The patients were being treated for cancers of the breast, lung, head, and neck or the pelvic region. The authors analyzed the impacts of several variables on patient learning, including anxiety, age, gender, support, referral, stage of illness, and diagnosis. Assessments were recorded before the simulation procedure and during the second and last weeks of treatment. RESULTS: The stepwise-information group was significantly less anxious before simulation (p = 0.02) and more satisfied (p = 0.001). Of the variables studied, only the support variable was associated with high state anxiety (p < 0.0001). CONCLUSIONS: Provision of patient information in a stepwise format leads to less treatment-related anxiety and greater patient satisfaction among radiation therapy patient undergoing simulation.

Adult↗
PubMed2000

Automatic on-line electronic portal image analysis with a wavelet-based edge detector.

A fully automatic method for on-line electronic portal image analysis is proposed. The method uses multiscale edge detection with wavelets for both the field outline and the anatomical structures. An algorithm to extract and combine the information from different scales has been developed. The edges from the portal image are aligned with the edges from the reference image using chamfer matching. The reference is the first portal image of each treatment. The matching is applied first to the field and subsequently to the anatomy. The setup deviations are quantified as the displacement of the anatomical structures relative to the radiation beam boundaries. The performance of the algorithm was investigated for portal images with different contrast and noise level. The automatic analysis was used first to detect simulated displacements. Then the automatic procedure was tested on anterior-posterior and lateral portal images of a pelvic phantom. In both sets of tests the differences between the measured and the actual shifts were used to quantify the performance. Finally we applied the automatic procedure to clinical images of pelvic and lung regions. The output of the procedure was compared with the results of a manual match performed by a trained operator. The errors for the phantom tests were small: average standard deviation of 0.39 mm and 0.26 degrees and absolute mean error of 0.31 mm and 0.2 degrees were obtained. In the clinical cases average standard deviations of 1.32 mm and 0.6 degrees were found. The average absolute mean errors were 1.09 mm and 0.39 degrees. Failures were registered in 2% of the phantom tests and in 3% of the clinical cases. The algorithm execution is approximately 5 s on a 168 MHz Sun Ultra 2 workstation. The automatic analysis tool is considered to be a very useful tool for on-line setup corrections.

Automation↗
PubMed2000

A computerized remote table control for fast on-line patient repositioning: implementation and clinical feasibility.

A computerized remote control for a Siemens ZXT treatment couch was implemented and its characteristics were investigated to establish its feasibility for on-line setup corrections, using portal imaging. Communication with the table was obtained by connecting it via a serial line to a work station. The treatment couch enables "goto" commands in the three main directions and around the isocenter. The accuracy of the movements after giving such a command was checked and the time for each movement was recorded. First, the movements into a single direction were studied (range of -4 to +4 cm and -4 degrees to +4 degrees). Each command was repeated four times. Second, the table was moved into the three main directions simultaneously. For this experiment a clinically relevant three-dimensional (3-D) normal distribution of shifts was used [N = 200, standard deviation (SD) 5 mm in the three main directions]. This latter experiment was done twice: without and with rotations (a distribution with SD 1 degrees). During the first experiment, with shifts into one direction, no systematic deviations were found. The overall accuracy of the shifts was 0.6 mm (1 SD) in each direction and 0.04 degrees (1 SD) for the rotations. The time required for a translation ranged between 4 and 13 s and for the rotation between 8 and 20 s. The second experiment with the 3-D distribution of setup errors yielded an error in the 3-D vector length equal to 0.96 mm (1 SD), independent of rotations. Shifts were performed in less than 11 s for 95% of the cases without rotations. When rotations were also performed, 95% of the movements finished in less than 16 s. In conclusion, the table movements are accurate and enable on-line setup corrections in daily clinical practice.

Feasibility Studies↗
PubMed1999

Assessment of the uncertainties in dose delivery of a commercial system for linac-based stereotactic radiosurgery.

PURPOSE: Linac-based stereotactic radiosurgery (SRS) was introduced in our department in 1992, and since then, more than 200 patients have been treated with this method. An in-house-developed algorithm for target localization and dose calculation has recently been replaced with a commercially available system. In this study, both systems have been compared, and positional accuracy, as well as dose calculation, have been verified experimentally. METHODS AND MATERIALS: The in-house-developed software for target localization and dose calculation is an extension to George Sherouse's GRATIS(R) software for radiotherapy treatment planning, and has been replaced by a commercial (BrainSCAN version 3.1; BrainLAB, Germany) treatment planning system (TPS) for SRS. The positional accuracy for the entire SRS procedure (from image acquisition to treatment) has been investigated by treatment of simulated targets in the form of 0.2-cm lead beads inserted into an anthropomorphic phantom. Both dose calculation algorithms have been verified against manual calculations (based on basic beam data and CT data from phantom and patients), and measurements with the anthropomorphic phantom applying ionization chamber, thermoluminescent detectors, and radiographic film. This analysis has been performed on a variety of experimental situations, starting with static beams and simple one-arc treatments, to more complex and clinical relevant applications. Finally, 11 patients have been evaluated with both TPS in parallel for comparison and continuity of clinical experience. RESULTS: Phantom studies evaluating the entire SRS procedure have shown that a target, localized by CT, can be irradiated with a positional accuracy of 0.08 cm in any direction with 95% confidence. Neglecting the influence of dose perturbation when the beam passes through bone tissue or air cavities, the calculated dose values obtained from both TPSs agreed within 1% (SD 1%) for phantom and patient studies. The application of a one-dimensional path length correction for tissue heterogeneity influences the treatment prescription 4% on average (SD 1%), which is in compliance with theoretical predictions. The phantom measurements confirmed the predicted dose at isocenter within uncertainty for the different treatment schedules in this study. CONCLUSION: The full SRS procedure applied to an anthropomorphic phantom has been used as a comprehensive method to assess the uncertainties involved in dose delivery and target positioning. The results obtained with both TPSs are in agreement with AAPM Report 54, TG 42 and clinical continuity is assured. However, the use of a one-dimensional path length correction will result in an increase of 4% in dose prescription, which is slightly more than that predicted in the literature.

Algorithms↗
PubMed1999

Characteristics and clinical application of a treatment simulator with Ct-option.

BACKGROUND AND PURPOSE: The integration of a scanner for computed tomography (CT) and a treatment simulator (Sim-CT, Elekta Oncology Systems, Crawley, UK) has been studied in a clinical situation. Image quality, hounsfield units (HU) and linearity have been evaluated as well as the implications for treatment planning. The additional dose to the patient has also been highlighted. MATERIAL AND METHODS: Image data is acquired using an array of solid state X-ray detectors attached externally to the simulator's image intensifier. Three different fields of view (FOV: 25.0 cm, 35.0 cm and 50.0 cm) with 0.2 cm, 0.5 cm and 1.0 cm slice thickness can be selected and the system allows for an aperture diameter of 92.0 cm at standard isocentric height. The CT performance has been characterized with several criteria: spatial resolution, contrast sensitivity, geometric accuracy, reliability of hounsfield units and the radiation output level. The spatial resolution gauge of the nuclear associates quality phantom (NAQP) as well as modulation transfer functions (MTF) have been applied to evaluate the spatial resolution. Contrast sensitivity and HU measurements have been performed by means of the NAQP and a HU conversion phantom that allows inserts with different electron densities. The computed tomography dose index (CTDI) of the CT-option has been monitored with a pencil shaped ionization chamber. Treatment planning and dose calculations for heterogeneity correction based on the Sim-CT images generated from an anthropomorphic phantom as well as from ten patients have been compared with similar treatment plans based on identical, yet diagnostic CT (DCT) images. RESULTS: The last row of holes that are resolved in the spatial resolution gauge of the NAQP are either 0.150 cm or 0.175 cm depending on the FOV and the applied reconstruction filter. These are consistent with the MTF curves showing cut-off frequencies ranging from 5.3 lp/cm to 7.1 lp/cm. Linear regression analysis of HU versus electron densities revealed a correlation coefficient of 0.99. Contrast, pixel size and geometric accuracy are within specifications. Computed tomography dose index values of 0.204 Gy/As and 0.069 Gy/As have been observed with dose measurements in the center of a 16 cm diameter and 32 cm diameter phantom, respectively for large FOV. Small FOV yields CTDI values of 0.925 Gy/As and 0.358 Gy/As which is a factor ten higher than the results obtained from a DCT under similar acquisition conditions. The phantom studies showed excellent agreement between dose distributions generated with the Sim-CT and DCT HU. The deviations between the calculated settings of monitor units as well as the maximum dose in three dimensions were less than 1% for the treatment plans based on either of these HU both for pelvic as well as thoracic simulations. The patient studies confirmed these results. CONCLUSIONS: The CT-option can be considered as an added value to the simulation process and the images acquired on the Sim-CT system are adequate for dose calculation with tissue heterogeneity correction. The good image quality, however, is compromised by the relative high dose values to the patient. The considerable load to the conventional X-ray tube currently limits the Sim-CT to seven image acquisitions per patient and therefore the system is limited in its capability to perform full three-dimensional reconstruction.

Computer Simulation↗
PubMed1999

Prognostic factors in urothelial renal pelvis and ureter tumours: a multicentre Rare Cancer Network study.

To assess the prognostic factors in patients with transitional-cell carcinoma of the renal pelvis and/or ureter, a series of 138 patients with transitional-cell carcinoma of the renal pelvis and/or ureter was collected in a retrospective multicentre study. 12 patients with distant metastases were excluded from the statistical evaluation. All but 3 patients underwent radical surgery: nephroureterectomy (n = 71), nephroureterectomy and lymphadenectomy (n = 20), nephroureterectomy and partial bladder resection or transurethral resection (n = 20), nephrectomy (n = 10), and ureterectomy (n = 5). Sixty-one per cent (n = 77) of the tumours were located in the renal pelvis, and 21% (n = 27) in the ureter (both in 22 [17%]). Following surgery, residual tumour was still present in 33 patients (16 microscopic and 17 macroscopic). Postoperative radiotherapy was given to 45 (36%) patients. The median follow-up period was 39 months. In a median period of 9 months, 66% of the patients relapsed (34 local, 7 locoregional, 16 regional, and 24 distant). The 5- and 10-year survival were 29% and 19%, respectively, in all patients. In univariate analyses, statistically significant factors influencing the outcome were Karnofsky index, pT-classification, pN-classification, tumour localisation, grade, and residual tumour after surgery. Multivariate analysis revealed that independent prognostic factors influencing outcome were pT-classification, the existence of residual tumour, and tumour localisation. In patients with urothelial renal pelvis and/or ureter tumours, a radical surgical attitude is mandatory; and the presence of tumour in the ureter is associated with a poorer prognosis.

Aged↗
PubMed1999

Using appropriate comparisons in economic evaluations. An exercise in Belgium.

This paper considers standard effective treatments for non-Hodgkin's lymphoma and early breast cancer in premenopausal women. The literature assesses the treatments' effectiveness, and expected charges for different treatments in the context of the Belgian Health Insurance System are compared. Ovariectomy in breast cancer (770 ECU) and conventional chemotherapy in non-Hodgkin (2,745 lymphoma ECU) prove equally effective and are less costly in comparison with chemotherapy (1,904 ECU) in breast cancer or chemotherapy and autologous bone marrow transplantation (19,262 ECU) in non-Hodgkin's lymphoma. Further unbiased insights in competitive treatments' costs and outcome could save money and enhance developments in cancer care.

Belgium↗
PubMed1999

Accelerated radiotherapy, carbogen, and nicotinamide in glioblastoma multiforme: report of European Organization for Research and Treatment of Cancer trial 22933.

PURPOSE: A three-step phase I/II trial associating accelerated radiotherapy with carbogen (step 1, ARCO), with nicotinamide (step 2, ARN), or with both (step 3, ARCON) was conducted, the aim of which was to overcome the effects of proliferation and hypoxia as potential causes of tumor radioresistance in glioblastoma multiforme. PATIENTS AND METHODS: Radiotherapy consisted of 60 Gy delivered over 4 weeks in 1.5-Gy fractions twice daily, 5 days a week. Carbogen breathing was started 5 minutes before each fraction and continued until the end of each treatment session. Nicotinamide was given daily as a single oral dose of 85 mg/kg. RESULTS: A total of 115 patients with a median age of 55 years were registered. Of 107 eligible patients, 23 were registered in step 1, 28 in step 2, and 56 in step 3. The planned treatment was administered without any interruption in 72% of patients (86% in ARCO but 68% in ARN and ARCON). The incidence and severity of acute skin and mucous membrane toxicity were higher in patients who received nicotinamide (ie, the ARN and ARCON groups). Grade 1 to 2 gastrointestinal toxicity was observed in 44% of patients in the ARN group and 32% of patients in the ARCON group, but only in 8% of patients in the ARCO group. Eight percent of evaluated patients presented with abnormal liver test results at treatment completion. The dose of corticosteroids had to be increased in 44% of patients. Late neurologic side effects were similar in all treatment steps and were observed mostly in patients with disease progression. Median survival times for patients treated with ARCO, ARN, and ARCON were 10.1, 9.7, and 11.1 months, respectively. CONCLUSION: Feasibility of ARCO treatment was good but that of ARN and ARCON was only fair. This probably reflected the higher acute toxicity rate, particularly gastrointestinal, for patients receiving nicotinamide. The dose of corticosteroids had to be increased frequently during treatment, suggesting a higher than expected acute neurologic toxicity. Overall survival was similar in the three treatment steps and not different when compared with results of other series that used radiotherapy alone.

Administration, Inhalation↗