Background and purpose: Although intensity modulated radiation therapy is characterized by three-dimensional dose distributions which are often superior to those obtained with conventional treatment ...plans, its routine clinical implementation is partially held back by the complexity of the beam verification. This is even more so when a dynamic multileaf collimator (dMLC) is used instead of a segmented beam delivery. We have therefore investigated the possibility of using a commercially available, liquid-filled electronic portal imaging device (EPID) for the pre-treatment quality assurance of dynamically delivered dose distributions.
Methods and materials: A special acquisition mode was developed to optimize the image acquisition speed for dosimetry with the liquid-filled EPID. We investigated the accuracy of this mode for 6 and 18 MV photon beams through comparison with film and ion chamber measurements. The impact of leaf speed and pulse rate fluctuations was quantified by means of dMLC plans especially designed for this purpose. Other factors influencing the accuracy of the dosimetry (e.g. the need for build-up, remanence of the ion concentration in the liquid and bulging of the liquid at non-zero gantry angles) were studied as well. We finally compared dosimetric EPID images with the corresponding image prediction delivered without a patient in the beam.
Results: The dosimetric accuracy of the measured dose distribution is ∼2% with respect to film and ion chamber measurements. The accuracy declines when leaf speed is increased beyond 2 cm/s, but is fairly insensitive to accelerator pulse rate fluctuations. The memory effect is found to be of no clinical relevance. When comparing the acquired and expected distributions, an overall agreement of 3% can be obtained, except at areas of steep dose gradients where slight positional shifts are translated into large errors.
Conclusions: Accurate dosimetric images of intensity modulated beam profiles delivered with a dMLC can be obtained with a commercially available, liquid-filled EPID. The developed acquisition mode is especially suited for fast and accurate pre-treatment verification of the intensity modulated fields.
Background Although there is an increased risk of schizophrenia‐spectrum psychoses (SSP) in people with intellectual disability (ID), there is a paucity of research evidence into clinical ...presentation of the disorder in comparison with research into SSP in people without ID.
Aims The aims of the study were to compare clinical, functional, and social factors in patients with mild ID (ICD‐10: F70) and SSP (ICD‐10: F20–9) attending a specialist mental health service for people with ID, with a control group of patients without ID but with SSP attending a generic adult mental health (GAMH) outpatient clinic.
Method A total of 106 patients with SSP (53 with ID and 53 from GAMH) were assessed on psychopathological symptoms, functioning scales and quality of life. They were compared using chi‐squared and regression analysis where appropriate.
Results People with ID and SSP appear to be more debilitated by the co‐occurring disorder than those with the same disorder but without ID. Increases in observable psychopathology and ‘negative’ schizophrenic symptoms, and decreased functional abilities were observed in the group with ID when compared to the GAMH group. The clinical implications of these findings are discussed.
Atypical antipsychotics are the first-line treatment for psychosis and are commonly used for behavioural problems in people with intellectual disabilities (ID), but a comprehensive evidence base for ...this approach is lacking. We studied prescription trends and the clinical effectiveness of risperidone and olanzapine in people with ID in a clinical, naturalistic setting. The results suggest that both drugs are well tolerated and effective in treating target symptoms across a range of diagnoses and ID. Both risperidone and olanzapine appear to reach full efficacy within 3 months, after which improvement reaches a plateau, as reflected in the Clinical Global Impression-Improvement scale. Compliance with both drugs is high. Olanzapine tended to be prescribed mostly for psychotic disorders, and showed good rates of response, whereas risperidone was prescribed mostly for people with behavioural disturbance associated with a psychiatric diagnosis. Furthermore, approximately one-quarter of the risperidone group were prescribed the medication for a behavioural disorder associated with a pervasive developmental disorder. Again, the medication was broadly effective in treatment. Both medications were also used to effectively treat affective disorders in a small percentage of patients. This study appears to indicate that both medications could be of significant clinical benefit for people with ID across a wide range of diagnoses and level of ID, although further controlled trials are required.
Background Malignant melanoma is a skin cancer of which the incidence is said to be raising in recent years. Prevention may result in decrease of the incidence. Early detection may result in the ...detection of earlier stages of the disease. In Limburg a combined campaign of prevention and screening has been performed in recent years and its effects should be evaluated. Objectives To study time trends of malignant melanoma incidence and the evolution of stages of detected melanomas and to relate them to interventions in previous years. Methods An ongoing multi-faceted intervention, including information as well as screening invitations (Euromelanoma project) was implemented in 1999. Time trends of malignant melanoma were studied on the basis of data from the Limburg Cancer Registry (LIKAR) of 1996-2005. Stages were studied on the basis of an additional clinical registration completed by pathologists and dermatologists. Results Over the years 1996-2005, the crude incidence rate of malignant melanoma was 6.8/100,000 patient-years in males and 11.6 in females, with a European standardized incidence rate (ESR) of 6.4 in males and 10.5 in females. The incidence progressively increased with age. In males, the ESR initially decreased, followed by a significant increase from 3.0 in 1998 to 7.6 in 2005. On average this is a yearly increase of 0.5 per 100,000 persons (p= 0.04). In females the curve fluctuates, resulting in almost similar rates in 1996 and 2004 (p = 0.85), but with a sudden increase from 9.2 to 15.8 between 2004 and 2005. Neither the Breslow nor the Clarck classification showed any significant change over the registration period. The proportion of lymph node invasion, metastasis and ulcerations did not change. Discussion With the exception of a small and clinically irrelevant increase in ESR in males, no changes over time were detected in incidence or stage distribution. The effect of the intervention seems limited.
Background The efficacies of granisetron plus dexamethasone and dexamethasone alone in controlling delayed nausea and vomiting after cisplatin chemotherapy (≥69 mg/m2) were compared in a multicentre, ...double-blind, placebo-controlled comparative study. Patients and methods In all, 654 patients (of whom 619 were evaluable) received prophylactic granisetron plus dexamethasone before chemotherapy on day 0; on day 1 complete responders and non-responders were randomized separately to receive dexamethasone, 8 mg b.d. p.o., with either granisetron, 1 mg b.d. p.o., or matching placebo for six days. Results Over days 1–6 the complete response rates were 54.5% (dexamethasone group) and 52.1% (dexamethasone plus granisetron group). Response rates were higher over days 4–6 (71.8% and 70.7%, respectively) than over days 1–3 (60.4% and 57.9%, respectively). Significantly more patients who responded to antiemetic treatment during day 0 were responders over days 1–6 (63% vs. 17% P < 0.001). No other treatment-related differences were found. Adverse events tended to be minor, with constipation and headache the most common. Overall, there were no significant differences in the safety profiles of the two regimens, but constipation and abdominal pain were significantly more common in the dexamethasone plus granisetron group. Conclusions Granisetron plus dexamethasone did not appear to confer additional benefit over use of dexamethasone alone in controlling delayed nausea and vomiting following cisplatin chemotherapy. Control of acute nausea and vomiting, however, appeared to be an important factor influencing delayed nausea and vomiting.
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