1/8. Absence of multiple local minima effects in intensity modulated optimization with dose-volume constraints.This paper reports on the analysis of intensity modulated radiation treatment optimization problems in the presence of non-convex feasible parameter spaces caused by the specification of dose-volume constraints for the organs-at-risk (OARs). The main aim was to determine whether the presence of those non-convex spaces affects the optimization of clinical cases in any significant way. This was done in two phases: (1) Using a carefully designed two-dimensional mathematical phantom that exhibits two controllable minima and with randomly initialized beamlet weights, we developed a methodology for exploring the nature of the convergence characteristics of quadratic cost function optimizations (deterministic or stochastic). The methodology is based on observing the statistical behaviour of the residual cost at the end of optimizations in which the stopping criterion is progressively more demanding and carrying out those optimizations to very small error changes per iteration. (2) Seven clinical cases were then analysed with dose-volume constraints that are stronger than originally used in the clinic. The clinical cases are two prostate cases differently posed, a meningioma case, two head-and-neck cases, a spleen case and a spine case. Of the 14 different sets of optimizations (with and without the specification of maximum doses allowed for the OARs), 12 fail to show any effect due to the existence of non-convex feasible spaces. The remaining two sets of optimizations show evidence of multiple minima in the solutions, but those minima are very close to each other in cost and the resulting treatment plans are practically identical, as measured by the quality of the dose-volume histograms (DVHs). We discuss the differences between fluence maps resulting from those similar treatment plans. We provide a possible reason for the observed results and conclude that, although the study is necessarily limited, the annealing characteristics of a simulated annealing method may not be justified in clinical optimization in the presence of dose-volume constraints. The results of optimizations by the Newton gradient (NG) method with a quadratic cost function are reported in detail. An adaptive simulated annealing method, optimizing the same function, and the dynamically penalized likelihood method, optimizing a log likelihood function, have also been used in the study. The results of the latter two methods have only been discussed briefly, as they yielded the same conclusions as the NG method.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
2/8. Creative novation behaviour therapy as a prophylactic treatment for cancer and coronary heart disease: Part I--Description of treatment.This paper describes a novel method of behaviour therapy applied to cancer-prone and coronary heart disease-prone patients in a prophylactic manner, to reduce the probability of their dying of cancer or coronary heart disease. The treatment can also be applied to patients already suffering from cancer in order to prolong their lives. The methods used are described in considerable detail, together with the rationale leading to their adoption. In Part II of this paper are the results of several studies showing that the methods are surprisingly successful in preventing death in cancer-prone and coronary heart disease-prone probands, and prolonging life in patients already suffering from terminal disease.- - - - - - - - - - ranking = 5keywords = behaviour (Clic here for more details about this article) |
3/8. Centriolar abnormalities in human neoplasms.The fine structure of centriolar precursors was studied in three human neoplasm: a chief cell adenoma of the parathyroid, an undifferentiated cell adenoma of the pituitary and a malignant lymphoma of the thyroid arising in Hashimoto's thyroiditis. Morphological evidence has been presented in support of the view that micochondria may serve as progenitors of centrioles. The sequence of events of mitochondrial centriole formation, from the early accumulation of electron dense substance at one pole of the mitochrondrion to the fully developed organelle, is documented. The findings indicate that centriolar abnormalities, such as multiplicity, accumulation or precursors, etc., may occur in benign and malignant, epithelial and mesenchymal tumors showing no apparent correlations with the biological behaviour of the neoplasms.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
4/8. Scope of scanning electron microscopy, transmission electron microscopy and freeze fracture technique in diagnostic cytology of effusions.A review of the literature on the application of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to cytodiagnosis of neoplastic cells in effusion fluid reveals a lack of consensus as to which of the techniques is most beneficial to a cytologist for a satisfactory diagnosis. The purpose of this study is therefore to critically evaluate the relative merits of SEM, TEM and freeze-fracture (FF) techniques in enhancing the diagnostic "sensitivity" of ultrastructural cytology. Two cases of adenocarcinoma, one case of mesothelioma and one case of small cell undifferentiated carcinoma of the lung were studied in detail by SEM, TEM and FF techniques. A comparative analysis of the results demonstrates that SEM is a rapid and useful technique where the microvilli on the tumour cell surface is the most prominent feature especially in adenocarcinomas. The major handicap of SEM becomes evident in cases where the extreme variability of the surface morphology amongst tumour cells makes it difficult to establish a diagnosis with confidence. TEM along with light microscopy (LM) of toluidine blue sections gives us the most comprehensive method for cyto-diagnosis and is particularly useful in cases where LM cytology alone is inconclusive. It has the added advantage of revealing diagnostically significant nuclear and cytoplasmic features which are helpful in differentiating a benign from a malignant cell and in some instances the probable site of the primary neoplasm. FF technique, though not conducive to a routine diagnostic situation, is of benefit in demonstrating the organization of junctional complexes. From preliminary studies it appears that the tight junctions in adenocarcinoma are different from those seen in small cell carcinoma. In mesothelioma, gap junctions are invariably present, but they are not seen prominently in adenocarcinoma or small cell carcinoma. Thus in poorly differentiated tumours where LM and TEM are inconclusive, FF may prove useful. It is concluded that such coordinated studies in the future have the potential to better our understanding of the nature and behaviour of tumour cells in effusion fluid.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
5/8. Behavioural analysis and control of psychosomatic symptoms of patients receiving intensive cancer treatment.During the course of cancer treatment behavioural symptoms such as gagging, coughing and vomiting often develop in the absence of apparent tissue damage. Moreover, symptoms whose onsets are clearly related to disease processes often continue after the disease has been eliminated. The reported research incorporated time-series analyses of patients' behavioural symptoms and assessments of behavioural interventions involving the modification of nurse--patient and family--patient interactions. Results showed that: (1) inadvertent social reinforcement by hospital staff and family members fosters the development of behavioural symptoms; (2) personnel associated with treatment can become discriminative stimuli for social attention and thereby evoke symptom behaviours; and (3) by modifying the social reinforcement contingencies associated with treatment protocols, the frequency of psychosomatic symptoms can be reduced without changing the quality of medical/nursing care and social interaction.- - - - - - - - - - ranking = 5keywords = behaviour (Clic here for more details about this article) |
6/8. hyperalgesia and myoclonus in terminal cancer patients treated with continuous intravenous morphine.Eight cancer patients in the terminal stages of the disease treated with high doses of intravenous morphine developed hyperalgesia. All cases were retrospectively sampled from three different hospitals in Copenhagen. Five patients developed universal hyperalgesia and hyperesthesia which in 2 cases were accompanied by myoclonus. In 3 patients a pre-existing neuralgia increased to excruciating intensity and in 2 of these cases myoclonus occurred simultaneously. Although only few clinical descriptions of the relationship between hyperalgesia/myoclonus and high doses of morphine are available, experimental support from animal studies indicates that morphine, or its metabolites, plays a causative role for the observed behavioural syndrome. The possible mechanisms are discussed and treatment proposals given suggesting the use of more efficacious opioids with less excitatory potency in these situations.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
7/8. Adjuvant psychological therapy for cancer patients.Adjuvant psychological therapy (APT), a brief, problem-focused, cognitive-behavioural treatment for patients with cancer, is described. A previously published randomized trial demonstrated a significant reduction in cancer-related emotional distress. APT is recommended for cancer patients suffering from such distress.- - - - - - - - - - ranking = 1keywords = behaviour (Clic here for more details about this article) |
8/8. Malignancy may adversely influence the quality and behaviour of oocytes.A case series of eight cycles of in-vitro fertilization (IVF) in five women diagnosed with malignant disorders is presented. These patients chose to defer definitive treatment for a chance for preservation of potential fertility. The response of these patients to ovarian stimulation, and the outcome, was compared with 17 IVF cycles in 12 age-matched patients with isolated tubal infertility. An apparent adverse influence of malignant disease on the quality and behaviour of oocytes was observed. Despite a comparable total number of oocytes per cycle in the two groups, a significantly reduced percentage of mature oocytes was retrieved per cycle from patients with malignant diseases. The oocytes from patients with malignant disorders were of a poorer quality and exhibited a significantly impaired fertilization rate compared to the controls. We propose that neoplastic processes, irrespective of the site or cell of origin, may have a detrimental impact on the biology of oocytes, an effect akin to that seen on spermatozoa in men with certain malignancies.- - - - - - - - - - ranking = 5keywords = behaviour (Clic here for more details about this article) |