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1.
Br J Cancer ; 113(5): 802-8, 2015 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-26241816

RESUMO

BACKGROUND: To present an overview of patient-reported sexual toxicity in sexually active long-term prostate cancer survivors treated with radiation therapy. METHODS: We used patient-reported outcomes from a study-specific questionnaire surveying symptoms after prostate cancer radiation therapy. Data from 518 men treated at the Sahlgrenska University Hospital in Sweden from 1993 to 2006 were analysed. The men had undergone primary or salvage external beam radiation therapy (EBRT) or EBRT combined with high-dose rate brachytherapy (BT). We also used information from 155 non-treated reference men from the general population with no history of prostate cancer, matched for age and residency. RESULTS: Median time from treatment to follow-up was 5 years (range: 1-14 years). Among the 16 investigated symptoms on erectile function, libido, orgasm, and seminal fluid, 9 symptoms in the primary EBRT group and 10 in both the salvage EBRT and the EBRT+BT groups were statistically significantly more prevalent in survivors than in reference men. Erectile dysfunction was influenced by both age and time to follow-up, whereas symptoms relating to orgasm and seminal fluid were influenced by time to follow-up only. Not being sexually active was almost one and a half times as common in survivors as in reference men. CONCLUSIONS: The presented symptom profiles can help to develop personalized therapy for prostate cancer through a better understanding of which radiation-induced toxicities to be addressed in the clinic and can also assist in identifying suitable interventions for existing symptoms.


Assuntos
Disfunção Erétil/epidemiologia , Neoplasias da Próstata/radioterapia , Lesões por Radiação/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Disfunção Erétil/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Lesões por Radiação/etiologia , Sobreviventes , Resultado do Tratamento
2.
Acta Anaesthesiol Scand ; 58(6): 701-8, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24819749

RESUMO

BACKGROUND: Mortality prediction is important in intensive care. The Simplified Acute Physiology Score (SAPS) II is a tool for predicting such mortality. However, the original SAPS II is poorly calibrated to current intensive care unit (ICU) populations because it draws on data, which is more than 20 years old. We aimed to improve the calibration of SAPS II using data from the Norwegian Intensive Care Registry (NIR). This is the first recalibration of SAPS II for Nordic data. METHODS: A first-level customization was applied to improve calibration of the original SAPS II model (Model A). NIR data used covered more than 90% of adult patients admitted to ICUs in Norway from 2008 to 2010 (n = 30712). RESULTS: The modified SAPS II, Model B, outperformed the original Model A with respect to calibration. Model B gave more accurate predictions of mortality than Model A (Hosmer-Lemeshow's C: 22.01 vs. 689.07; Brier score: 0.120 vs. 0.131; Cox's calibration regression: α = -0.093 vs. -0.747, ß = 0.921 vs. 0.735, (α|ß = 1) = -0.009 vs. -0.630). The standardized mortality ratio was 0.73 [95% confidence interval (CI) of 0.70-0.76] for Model A and 0.99 (95% CI of 0.95-1.04) for Model B. Discrimination was good for both models (area under receiver operating characteristic curve = 0.83 for both models). CONCLUSIONS: As expected, Model B is better calibrated than Model A, and both models have similar uniformity of fit and equal discrimination. Introducing Model B into Norwegian ICUs may improve precision in decision-making. Units will have a more realistic benchmark for the assessment of ICU performance. Mortality risk estimates from Model B are better than previous SAPS II estimates have been.


Assuntos
Cuidados Críticos , Estado Terminal/mortalidade , Mortalidade Hospitalar , Índice de Gravidade de Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Calibragem , Feminino , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Noruega/epidemiologia , Prognóstico , Sistema de Registros
3.
Br J Cancer ; 108(10): 1964-70, 2013 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-23632483

RESUMO

BACKGROUND: The objective of this study is to provide comprehensive overviews of patient-reported urinary symptoms for long-term prostate cancer survivors treated with radiation therapy and for untreated, healthy men. METHODS: We performed a population-based cross-sectional study using a study-specific postal questionnaire assessing symptoms among 1007 men consecutively treated at the Sahlgrenska University Hospital, Göteborg, Sweden from 1993-2006 (primary or salvage external beam radiation therapy (EBRT) or EBRT and high-dose rate brachytherapy). We also randomly recruited 350 non-pelvic-irradiated matched control men from the Swedish Total Population Register. Symptom prevalence and prevalence ratios were computed. RESULTS: Survey participation rate was 89% (874/985) for eligible survivors and 73% (243/332) for eligible controls. Median time from treatment to follow-up was 5 years (range, 1-14 years). Among the 21 investigated symptoms reflecting obstruction, frequency, urgency, pain and incontinence, we found significantly higher prevalence compared with controls for 9 symptoms in the EBRT group, 10 in the EBRT+brachytherapy group and 5 in the salvage EBRT group. The prevalence for a majority of the symptoms was stable over time. CONCLUSION: The presented toxicity profiles provide a thorough understanding of patient-reported urinary symptoms that can assist in developing personalised therapy for prostate cancer.


Assuntos
Doenças Urogenitais Masculinas/etiologia , Neoplasias da Próstata/radioterapia , Lesões por Radiação/epidemiologia , Autorrelato , Sobreviventes/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Braquiterapia/efeitos adversos , Braquiterapia/métodos , Estudos Transversais , Humanos , Masculino , Doenças Urogenitais Masculinas/epidemiologia , Pessoa de Meia-Idade , Neoplasias da Próstata/epidemiologia , Neoplasias da Próstata/mortalidade , Lesões por Radiação/etiologia , Inquéritos e Questionários , Suécia/epidemiologia
4.
Br J Cancer ; 105(6): 737-45, 2011 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-21847122

RESUMO

BACKGROUND: We surveyed the occurrence of physical symptoms among long-term gynaecological cancer survivors after pelvic radiation therapy, and compared with population-based control women. METHODS: We identified a cohort of 789 eligible gynaecological cancer survivors treated with pelvic radiation therapy alone or combined with surgery in Stockholm or Gothenburg, Sweden. A control group of 478 women was randomly sampled from the Swedish Population Registry. Data were collected through a study-specific validated postal questionnaire with 351 questions concerning gastrointestinal and urinary tract function, lymph oedema, pelvic bones and sexuality. Clinical characteristics and treatment details were retrieved from medical records. RESULTS: Participation rate was 78% for gynaecological cancer survivors and 72% for control women. Median follow-up time after treatment was 74 months. Cancer survivors reported a higher occurrence of symptoms from all organs studied. The highest age-adjusted relative risk (RR) was found for emptying of all stools into clothing without forewarning (RR 12.7), defaecation urgency (RR 5.7), difficulty feeling the need to empty the bladder (RR 2.8), protracted genital pain (RR 5.0), pubic pain when walking indoors (RR 4.9) and erysipelas on abdomen or legs at least once during the past 6 months (RR 3.6). Survivors treated with radiation therapy alone showed in general higher rates of symptoms. CONCLUSION: Gynaecological cancer survivors previously treated with pelvic radiation report a higher occurrence of symptoms from the urinary and gastrointestinal tract as well as lymph oedema, sexual dysfunction and pelvic pain compared with non-irradiated control women. Health-care providers need to actively ask patients about specific symptoms in order to provide proper diagnostic investigations and management.


Assuntos
Neoplasias dos Genitais Femininos/diagnóstico , Neoplasias dos Genitais Femininos/radioterapia , Radioterapia/efeitos adversos , Sobreviventes , Adulto , Idoso , Canal Anal/fisiopatologia , Estudos de Casos e Controles , Estudos de Coortes , Terapia Combinada , Feminino , Seguimentos , Neoplasias dos Genitais Femininos/fisiopatologia , Humanos , Pessoa de Meia-Idade , Vigilância da População , Sistema de Registros , Inquéritos e Questionários , Sistema Urinário/fisiopatologia
5.
J Med Ethics ; 36(8): 473-8, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20663764

RESUMO

INTRODUCTION: Hundreds of thousands of premature neonates born in low-income countries are implicitly denied treatment each year. Studies from India show that treatment is rationed even for neonates born at 32 gestational age weeks (GAW), and multiple external factors influence treatment decisions. Is withholding of life-saving treatment for children born between 28 and 32 GAW acceptable from an ethical perspective? METHOD: A seven-step impartial ethical analysis, including outcome analysis of four accepted priority criteria: severity of disease, treatment effect, cost effectiveness and evidence for neonates born at 28 and 32 GAW. RESULTS: The ethical analysis sketches out two possibilities: (a) It is not ethically permissible to limit treatment to neonates below 32 GAW when assigning high weight to health maximisation and overall health equality. Neonates below 32 GAW score high on severity of disease and efficiency and cost-effectiveness of treatment if one gives full weight to early years of a newborn life. It is in the child's best interest to be treated. (b) It can be considered ethically permissible if high weight is assigned to reducing inequality of welfare and maximising overall welfare and/or not granting full weight to early years of newborns is considered acceptable. From an equity-motivated health and welfare perspective, we would not accept (b), as it relies on accepting the lack of proper welfare policies for the poor and disabled in India. CONCLUSION: Explicit priority processes in India for financing neonatal care are needed. If premature neonates are perceived as worth less than other patient groups, the reasons should be explored among a broad range of stakeholders.


Assuntos
Ética Médica , Alocação de Recursos para a Atenção à Saúde/ética , Unidades de Terapia Intensiva Neonatal/ética , Cuidados para Prolongar a Vida/ética , Assistência Terminal/ética , Peso ao Nascer , Comparação Transcultural , Tomada de Decisões , Eutanásia Passiva/ética , Feminino , Idade Gestacional , Humanos , Índia , Recém-Nascido , Recém-Nascido Prematuro , Unidades de Terapia Intensiva Neonatal/economia , Masculino , Seleção de Pacientes , Prognóstico , Fatores Socioeconômicos
6.
J Med Ethics ; 34(6): 478-83, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18511624

RESUMO

OBJECTIVE: To provide an ethical analysis of whether the Ethiopian and Tanzanian national HIV/AIDS treatment guidelines can be considered legitimate and fair rationing tools. METHOD: Qualitative study and ethical analysis involving guideline documents and interviews with nine key members involved in the development of the guidelines. The analysis followed an editing organising style. The theoretical framework was a guideline-specific framework based on theories of just resource allocation in healthcare and conditions that ensure fair processes in guideline development. According to this framework, legitimate rationing requires reasons for patient selection to be explicit, public and relevant, and decisions must be open to question and revision. RESULTS: The only explicit rationing criteria that both guidelines recommended were clinical antiretroviral treatment indications. Explicit non-clinical rationing criteria were expressed in a separate Ethiopian implementation guideline. Neither of the guideline development processes fully satisfies minimal requirements of procedural fairness. There is a lack of transparency. The reasons for decisions are rarely given and are not publicly available. This reduces the opportunity for public questioning, debate and revisions. The guidelines were based on expert opinion and consensus. Recommendations from the WHO were copied without much discussion, disagreement or adjustment. CONCLUSIONS: The two national HIV treatment guidelines discussed are de facto mechanisms for rationing but were developed using methods that do not fully satisfy the requirements of fair processes.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Alocação de Recursos para a Atenção à Saúde/ética , Seleção de Pacientes/ética , Guias de Prática Clínica como Assunto/normas , Contagem de Linfócito CD4 , Criança , Análise Ética , Etiópia , Feminino , Infecções por HIV/imunologia , Humanos , Entrevistas como Assunto , Gravidez , Tanzânia , Organização Mundial da Saúde
7.
Br J Radiol ; 81(965): 397-405, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18250121

RESUMO

A planning study was performed in order to investigate the potential benefits of intensity-modulated radiotherapy using a simultaneous integrated multi-target treatment technique (SIMT-IMRT) over highly optimized three-dimensional conformal radiotherapy combined with intracavitary brachytherapy (3D-CRT + IBT) for the treatment of nasopharyngeal carcinoma (NPC). The subjects were eight patients with Stages I-IV NPC. For each case, two sets of plans were prepared after delineation of gross tumour volumes, three planning target volumes (PTVs) and 17 organs at risk (OARs). Dose prescriptions for PTVs were 72.6 Gy, 66 Gy and 52.8 Gy in 33 fractions for SIMT-IMRT vs 72 Gy (66 Gy in 33 fractions for 3D-CRT and 3 Gy twice for IBT), 66 Gy (in 33 fractions) and 46 Gy (in 23 fractions) for 3D-CRT + IBT plans. Compared with the combined plans, SIMT-IMRT provided superior results for the primary tumour (PT) in terms of mean equivalent uniform dose (67 Gy vs 63.7 Gy, p = 0.016). IMRT plans increased the mean tumour control probability (TCP) values (both uncorrected and corrected for accelerated tumour repopulation after 28 days) for PT when compared with 3D-CRT + IBT (98% and 94.3% vs 95.8% and 89.9%, respectively, p = 0.016). Mean doses to middle/external ears, parotid glands and temporomandibular joints were significantly lower in IMRT plans. Our conclusion is that, for all stages of NPC, SIMT-IMRT was superior to highly optimized 3D-CRT + IBT in terms of tumour coverage, increased local TCP, and dose reduction to some OARs. We recommend that SIMT-IMRT should be considered as a first-line radiotherapy technique for NPC.


Assuntos
Braquiterapia/métodos , Neoplasias Nasofaríngeas/radioterapia , Radioterapia Conformacional/métodos , Radioterapia de Intensidade Modulada/métodos , Humanos , Dosagem Radioterapêutica , Resultado do Tratamento
8.
Eur J Cancer ; 39(4): 430-7, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12751372

RESUMO

In 1982, the European Organization for Research and Treatment of Cancer (EORTC) Radiotherapy Group established the Quality Assurance (QA) programme. During the past 20 years, QA procedures have become a major part of the activities of the group. The methodology and steps of the QA programme over the past 20 years are briefly described. Problems and conclusions arising from the results of the long-lasting QA programme in the EORTC radiotherapy group are discussed and emphasised. The EORTC radiotherapy group continues to lead QA in the European radiotherapy community. Future challenges and perspectives are proposed.


Assuntos
Neoplasias/radioterapia , Garantia da Qualidade dos Cuidados de Saúde , Ensaios Clínicos como Assunto , Europa (Continente) , Humanos , Radioterapia/normas , Radioterapia Adjuvante , Estudos Retrospectivos
9.
Clin Genet ; 62(1): 14-23, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12123481

RESUMO

The pancreas is a vital gland of exocrine and endocrine function. It is the target of two main affections: diabetes and pancreatic cancer. We describe the tissue interactions, signaling pathways and intracellular targets that are involved in the emergence of the pancreas primordium and its proliferation, morphogenesis and differentiation. It appears that several genes of developmental relevance have an adult function and are involved in pancreas affections. Embryological experimentation in animals contributed to provide candidate genes for human disease and holds promise for future treatments.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Pâncreas/embriologia , Pâncreas/fisiologia , Diferenciação Celular/genética , Diabetes Mellitus/etiologia , Diabetes Mellitus/genética , Humanos , Ilhotas Pancreáticas/embriologia , Ilhotas Pancreáticas/fisiologia , Morfogênese/genética , Pâncreas/anormalidades , Neoplasias Pancreáticas/etiologia , Neoplasias Pancreáticas/genética
10.
Endocrinology ; 142(12): 5311-20, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11713231

RESUMO

Mutations in the transcription factor hepatocyte nuclear factor-1 alpha (HNF-1 alpha) cause maturity-onset diabetes of the young 3, a severe form of diabetes characterized by pancreatic beta-cell dysfunction. We have used targeted expression of a dominant-negative mutant of HNF-1 alpha to specifically suppress HNF-1 alpha function in beta-cells of transgenic mice. We show that males expressing the mutant protein became overtly diabetic within 6 wk of age, whereas females displayed glucose intolerance. Transgenic males exhibited impaired glucose-stimulated insulin secretion, detected both in vivo and in the perfused pancreas. Pancreatic insulin content was markedly decreased in diabetic animals, whereas the glucagon content was increased. Postnatal islet development was altered, with an increased alpha-cell to beta-cell ratio. beta-Cell ultrastructure showed signs of severe beta-cell damage, including mitochondrial swelling. This animal model of maturity-onset diabetes of the young 3 should be useful for the further elucidation of the mechanism by which HNF-1 alpha deficiency causes beta-cell dysfunction in this disease.


Assuntos
Proteínas de Ligação a DNA , Diabetes Mellitus Tipo 2/genética , Expressão Gênica , Marcação de Genes , Genes Dominantes , Ilhotas Pancreáticas/fisiologia , Proteínas Nucleares , Fatores de Transcrição/genética , Animais , Feminino , Glucagon/metabolismo , Intolerância à Glucose/genética , Transportador de Glucose Tipo 2 , Fator 1 Nuclear de Hepatócito , Fator 1-alfa Nuclear de Hepatócito , Fator 1-beta Nuclear de Hepatócito , Insulina/metabolismo , Antagonistas da Insulina/farmacologia , Ilhotas Pancreáticas/ultraestrutura , Masculino , Camundongos , Camundongos Transgênicos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Mutação/fisiologia , Pâncreas/metabolismo , Fenótipo , Caracteres Sexuais , Fatores de Transcrição/farmacologia
11.
Tidsskr Nor Laegeforen ; 121(13): 1618-21, 2001 May 20.
Artigo em Norueguês | MEDLINE | ID: mdl-11446051

RESUMO

Three medical students describe their search for professional and personal identity midway through medical school. The article focuses on their concrete experience of human suffering and vulnerability, which is set against elements from the relational ethics of Danish philosopher KE Løgstrup. Løgstrup's ontology is based on a relational understanding of being human, and implicitly opposes the strongly objectivating and individualised view of human existence promoted through the experiences of everyday medical education.


Assuntos
Educação Médica , Ética Médica , Filosofia Médica , Estudantes de Medicina/psicologia , Existencialismo , Humanos , Relações Interpessoais
12.
Acta Oncol ; 40(8): 941-51, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11845959

RESUMO

The aim of this study was to evaluate normal tissue response by molecular markers to multifraction low doses of ionizing radiation, with the focus on changes in repopulation, estimated using Ki-67 as the proliferation marker, and on expressions of the p53 and p21 proteins, identified as key proteins in the DNA damage checkpoint. Repeated skin biopsies were taken from patients treated for prostate cancer with radiotherapy. The expressions of Ki-67, p53 and p21 of the keratinocytes in the basal cell layer of the epidermis were quantified immunohistochemically. The dose to the basal layer was 1.1 Gy per fraction, given five times per week for seven weeks. The indices of the three markers were determined over the whole period. A significant suppression of the Ki-67 index was observed during the first weeks, followed by a significant gradual increase in the Ki-67 index over the last weeks. The p53 and p21 protein levels were almost zero in the unirradiated skin. Upon irradiation, both the p53 and p21 index increased in a pattern very congruent to the Ki-67 index. In conclusion, daily fractions of about 1 Gy to the skin resulted in, for the keratinocytes in the basal layer, a cell growth arrest for a couple of weeks and a subsequent acceleration in repopulation during the following weeks of irradiation. The present findings also provided novel insights into the role of the p53/p21 pathway in the response of a normal epithelium to ionizing radiation as it is applied in radiotherapy.


Assuntos
Dano ao DNA , Antígeno Ki-67/biossíntese , Neoplasias da Próstata/radioterapia , Proteínas Proto-Oncogênicas p21(ras)/biossíntese , Lesões por Radiação/diagnóstico , Lesões por Radiação/fisiopatologia , Pele/efeitos da radiação , Proteína Supressora de Tumor p53/biossíntese , Biomarcadores/análise , Biópsia , Humanos , Imuno-Histoquímica , Antígeno Ki-67/análise , Masculino , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas p21(ras)/análise , Pele/patologia , Proteína Supressora de Tumor p53/análise
13.
Eur J Cancer ; 36(5): 615-20, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10738126

RESUMO

The European Organization for Research and Treatment of Cancer (EORTC) Radiotherapy Group initiated its mailed thermoluminescence dosimetry (TLD) programme in 1986. The aim of the present study was to evaluate the clinical relevance of variations in beam output detected in the period 1993 to 1996. A total of 140 beam outputs were checked (26 for cobalt-60 units and 114 for linear accelerators) in 35 centres. Clinical dose-response data for tumour control and normal tissue morbidity were used to assess the variation in clinical outcome resulting from variability in beam output. For 75 checked beams with nominal accelerating potentials (n. a.p.) of 6 MV or less the mean ratio, +/- standard deviation (S.D.) of measured to stated output was 1.004+/-0.020. For 65 beams with n. a.p. of 8 MV or more, the ratio was 1.009+/-0.021. Even with this relatively high level of precision, broad distributions of estimated tumour control or normal tissue morbidity were found. In the 10% of the beams with the most pronounced underdosage, the loss in tumour control probability was estimated at 7-8 percentage points. Likewise, in the 10% of the beams with the most pronounced overdosage, the increase in mild/moderate morbidity was 19-22 percentage points. For severe morbidity the same beams raised the estimated incidence of severe complications from 5% to 9-10%. An estimation of the loss of uncomplicated cure probability was about 1% for both high and low energy beams. Sequential mailings considerably improved the uniformity of clinical outcome. We conclude that small deviations in beam output may lead to clinically important variations in outcome. Substantial reductions in the variation between measured and stated output can be achieved by sequential mailings. Mailed TLD checks should be an integral part of a continuously ongoing quality assurance activity in radiotherapy.


Assuntos
Garantia da Qualidade dos Cuidados de Saúde , Dosagem Radioterapêutica/normas , Dosimetria Termoluminescente/normas , Relação Dose-Resposta à Radiação , Humanos , Valores de Referência
14.
Phys Med Biol ; 43(11): 3171-81, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9832009

RESUMO

This paper presents experimentally determined correction factors for Farmer-type chambers for absorbed dose determination in 60Co and 192Ir brachytherapy dosimetry. The correction factors were determined from measurements made in a PMMA phantom and calculation of ratios of measured charges. The ratios were corrected for the different volumes of the ionization chambers, determined in external high-energy electron beams. The correction factors for the central electrode effect and the wall material dependency in 60Co brachytherapy dosimetry agree with those used in external 60Co beam dosimetry. In 192Ir dosimetry, the central aluminium electrode increases the response of an NE2571 chamber compared with that of a chamber with a central graphite electrode. The increase is 1.1 and 2.1% at 1.5 and 5.0 g cm(-2) distance, respectively. Similar values are obtained with an NE2577 chamber. The wall correction factor in 192Ir dosimetry for a chamber with an A-150 wall has been determined to be 1.018, independent of the measurement distance. For a graphite walled chamber, the correction factor is 0.996 and 1.001 at 1.5 and 5.0 g cm(-2) distance, respectively. The values of the wall correction factors are evaluated by a theory presented. If the chamber is used according to the 'large cavity' principle, the correction factor to account for the replacement of the phantom material by the ionization chamber was determined to be 0.982 for an NE2571 chamber when used with a Delrin cap, and 0.978 for an NE2581 when used with a polystyrene cap. The correction factors for the 'large cavity' principle are valid at both 60Co and 192Ir qualities.


Assuntos
Braquiterapia , Radioisótopos de Cobalto/uso terapêutico , Radioisótopos de Irídio/uso terapêutico , Radiometria/instrumentação , Fenômenos Biofísicos , Biofísica , Braquiterapia/estatística & dados numéricos , Eletrodos , Grafite , Humanos , Imagens de Fantasmas , Polimetil Metacrilato , Poliestirenos , Radiometria/estatística & dados numéricos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador , Resinas Sintéticas , Água
15.
Phys Med Biol ; 43(11): 3183-94, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9832010

RESUMO

This paper presents two methods for absorbed dose determination with ionization chambers at short distance from 60Co and 192Ir brachytherapy sources. The methods are modifications of the Bragg-Gray and large cavity principles given in the IAEA code of practice for high- and medium-energy photon beams. A non-uniformity correction factor to account for the non-uniform electron fluence in the air cavity is introduced into the methods. The absorbed dose rates were determined from ionization chamber measurements at distances between 1.5 and 5.0 cm from the brachytherapy sources. The agreement between the two methods is excellent in 60Co brachytherapy dosimetry. For 192Ir dosimetry, the difference is less than 2.5% at all distances. In absorbed dose rate calculations with the 60Co brachytherapy source, the ratios between calculated and experimentally determined absorbed dose rates are 0.987 and 0.994 depending on the method used for absorption and scatter correction. In 192Ir dosimetry, the large cavity principle gives almost identical values to those which can be obtained with the AAPM recommendations. Using the chambers according to the Bragg-Gray principle in 192Ir dosimetry, the agreement with AAPM calculated absorbed dose rates is within 2.5% at all distances. The uncertainty, expressed as one standard deviation, in the experimentally determined absorbed dose is estimated to be between 3 and 4%.


Assuntos
Braquiterapia , Radioisótopos de Cobalto/uso terapêutico , Radioisótopos de Irídio/uso terapêutico , Algoritmos , Fenômenos Biofísicos , Biofísica , Braquiterapia/estatística & dados numéricos , Estudos de Avaliação como Assunto , Humanos , Radiometria/instrumentação , Radiometria/estatística & dados numéricos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos
16.
Phys Med Biol ; 43(6): 1497-506, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9651020

RESUMO

In radiotherapy with photon beams, the use of dynamic wedges, which are obtained by the movement of one of the jaws, offers an increasing flexibility relative to the traditional use of metal wedges. But it is a disadvantage for the measurement of absorbed dose distributions, because the absorbed dose at each measurement point can only be obtained after a complete movement of the jaw. Consequently, for radiotherapy planning, an algorithm should be available that does not require measurements for any specific dynamically wedged beam, but is based on only a modest number of measurements. In this paper, an algorithm for the calculation of the dose distribution from dynamic wedges is described. This algorithm uses the convolution of pencil beam kernels with a non-uniform field function. These pencil beam kernels are derived from empirical data resulting from measurements of the open beam only.


Assuntos
Fótons/uso terapêutico , Dosagem Radioterapêutica , Algoritmos , Fenômenos Biofísicos , Biofísica , Humanos , Modelos Teóricos , Neoplasias/radioterapia , Aceleradores de Partículas/instrumentação , Aceleradores de Partículas/estatística & dados numéricos , Imagens de Fantasmas , Tecnologia Radiológica
17.
Phys Med Biol ; 43(6): 1529-44, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9651023

RESUMO

The accuracy of the recently implemented three-dimensional electron beam dose calculating algorithm in CADPLAN version 2.62 manufactured by Varian Dosetek was investigated. The algorithm uses a generalized Gaussian pencil beam model and the dose distributions are calculated as the sum of three weighted Gaussians. To use the calculating program in an optimum way, one needs to know the dose calculation accuracy of the algorithm as well as its limitations. This investigation includes comparisons of measured relative dose distributions with calculated dose distributions and also comparisons of measured and calculated monitor units. The geometries tested were quadratic fields, irregularly shaped fields, oblique fields, irregularly shaped phantom surfaces and internal heterogeneities and were most often irradiated with 8 and 20 MeV electrons. The results indicate that the algorithm is well suited for clinical three-dimensional dose planning. Some deviations occurred but they were most often within the limits of international criteria of acceptability.


Assuntos
Algoritmos , Elétrons/uso terapêutico , Planejamento da Radioterapia Assistida por Computador , Fenômenos Biofísicos , Biofísica , Humanos , Dosagem Radioterapêutica , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Radioterapia de Alta Energia , Espalhamento de Radiação , Tecnologia Radiológica
18.
Eur J Cancer ; 34(13): 2068-75, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10070313

RESUMO

The aim was to quantify the risk of post-treatment sarcoma in breast cancer patients. All 122,991 women with a breast cancer from 1958 to 1992 in the Swedish Cancer Register were followed up for soft tissue sarcomas and 116 were found, giving a standardised incidence ratio of 1.9 (95% CI 1.5-2.2). The absolute risk was 1.3 per 10(4) person-years. The sarcomas were located in the breast region or on the ipsilateral arm in 63% (67/106). There were 40 angiosarcomas and 76 sarcomas of other types. In a case-control study, angiosarcoma correlated significantly with lymphoedema of the arm, odds ratio (OR) 9.5 (95% CI 3.2-28.0), but no correlation with radiotherapy was observed. For other types of sarcoma there was a correlation with the integral dose. The dose-response relationship indicated that the risk increased linearly with the integral dose to 150-200 J and stabilised at higher energies. The OR was 2.4 (95% CI 1.4-4.2) for an energy of 50 J, approximately corresponding to the radiation of the breast after breast-conserving surgery. Thus, only oedema of the arm correlated with angiosarcoma, but for other types of sarcoma the integral dose of radiotherapy was a predictor of the risk.


Assuntos
Neoplasias da Mama/radioterapia , Neoplasias Induzidas por Radiação/etiologia , Sarcoma/etiologia , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/epidemiologia , Estudos de Casos e Controles , Relação Dose-Resposta à Radiação , Feminino , Hemangiossarcoma/radioterapia , Humanos , Incidência , Linfedema/radioterapia , Pessoa de Meia-Idade , Neoplasias Induzidas por Radiação/epidemiologia , Sistema de Registros , Fatores de Risco , Sarcoma/epidemiologia
19.
Radiother Oncol ; 45(1): 63-70, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9364633

RESUMO

BACKGROUND AND PURPOSE: Conformal treatment planning with megavoltage X-rays and protons was studied in an attempt to determine if there are advantage of boost therapy with protons instead of X-rays for a patient with a tumour growing around the cervical spinal cord. MATERIALS AND METHODS: A patient with a Ewing sarcoma was selected for the model study. The proton boost plan was realised with a six beam patched technique. Several X-ray boost techniques were planned, some not yet practically realisable. The techniques giving the best dose distributions and the best tumour control probabilities in the absence of significant late toxicity were looked for. The boost techniques were added to two large lateral X-ray beams covering the planning target volume (PTV) and the main risk organ, the spinal cord. The evaluation was made with two biological models, i.e. the tumour control probability (TCP) model, proposed by Webb and Nahum (Webb, S. and Nahum, A.E. A model for calculating tumour control probability in radiotherapy including the effect of inhomogeneous distributions of dose and clonogenic cell density. Phys. Med. Biol. 38: 653-666, 1993), and the normal tissue complication probability (NTCP) model, first derived by Lyman (Lyman, J.T. Complication probability as assessed from dose-volume histograms. Radiat. Res. 104: s13-s19, 1985). RESULTS: The comparison showed small but clear advantages of protons for the boost. At 1% NTCP in the spinal cord, the calculated TCP was on average 5% higher. However, depending on the values of the parameters chosen in the biological models, the gain for protons varied from 0-10%. The smallest gains were seen in radiosensitive tumours for which the TCP was close to 100% with any of the techniques and in radioresistant tumours for which neither technique resulted in any appreciable probability of local cure. CONCLUSION: Protons appear to have therapeutic advantages over conventional radiotherapy in tumours with relatively high radiosensitivity situated close to the spinal cord.


Assuntos
Vértebras Cervicais , Cuidados Paliativos/métodos , Terapia com Prótons , Radioterapia de Alta Energia/métodos , Sarcoma de Ewing/radioterapia , Neoplasias da Coluna Vertebral/radioterapia , Adulto , Relação Dose-Resposta à Radiação , Humanos , Masculino , Dosagem Radioterapêutica , Radioterapia de Alta Energia/instrumentação
20.
Radiother Oncol ; 44(3): 237-44, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9380822

RESUMO

PURPOSE: To evaluate the treatment outcome after radical radiotherapy of localized prostate cancer in 50 patients (38 patients with stage T1-2 and 12 patients with stage T3) after a median follow-up time of 45 months (range 18-92 months). METHODS: The treatment was given by combination of external beam radiotherapy (50 Gy) and brachytherapy (2 x 10 Gy). The brachytherapy was given using TRUS-guided percutaneously inserted temporary needles with a high dose rate remote afterloading technique with Ir-192 as the radionuclide source. Three target definitions and dose levels inside the prostate gland were used. Local control was evaluated by digital rectal examination, TRUS-guided biopsies and serum PSA evaluations. RESULTS: Clinical and biopsy verified local control was achieved in 48 of the 50 (96%) patients; for stage T1-2 in 37 of 38 (97%) patients and for stage T3 in 11 of 12 (92%) patients. A posttreatment serum PSA level < or =1.0 ng/ml was seen in 42 (84%) patients, values from >1.0 to < or =2.0 ng/ml were seen in four (8%) patients and values exceeding 2.0 were seen in four (8%) patients. The late toxicity was minimal. CONCLUSION: The local control results and the minimal toxicity after the combined radiotherapy treatment are promising. However, long term results are necessary before general use.


Assuntos
Braquiterapia/métodos , Radioisótopos de Irídio/uso terapêutico , Neoplasias da Próstata/radioterapia , Idoso , Braquiterapia/efeitos adversos , Relação Dose-Resposta a Droga , Gastroenteropatias/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Ereção Peniana/efeitos da radiação , Antígeno Prostático Específico/sangue , Neoplasias da Próstata/patologia , Lesões por Radiação/etiologia , Resultado do Tratamento , Transtornos Urinários/etiologia
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