The Urinary Tract

Stewart, F. A.; Williams, Michael

doi:10.1007/978-3-642-83416-5_14

Cited by 28 publications

(11 citation statements)

References 107 publications

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“…Experimental data are generally well described by an LQ model, and a=b ratios of 2-3 Gy fit most of the experimental data for doses per fraction of 2-10 Gy (Stewart and Williams, 1991;Joiner et al, 1992). Estimates of repair half-times are of the order of 1.3-2 h (Van Rongen et al, 1990a;Joiner et al, 1993).…”

Section: Kidneysmentioning

confidence: 84%

“…Patients with proteinuria may have apparently normal renal function, although their reserve renal function is impaired and renal failure may occur after stress. Benign hypertension is usually accompanied by proteinuria, and may lead to cardiovascular problems if not treated (Stewart and Williams, 1991;Cassady, 1995). Hypertension after renal irradiation is the result of increased production of angiotensin II, but it is not clear whether this is mediated by increased secretion of renin, due to radiation-induced vascular damage and ischaemia, or whether this occurs independent of circulating renin levels.…”

Section: Kidneysmentioning

confidence: 99%

“…Symptoms of the acute phase of damage include frequency, urgency, and dysuria. The underlying cause of these symptoms is inflammation (hyperaemia and oedema), sometimes complicated by bacterial infection, which is treatable with antibiotics (Stewart and Williams, 1991).…”

Section: Bladder and Uretersmentioning

confidence: 99%

“…This is usually initiated in the basal layer, although cells of all ploidy levels are capable of division. In contrast, stimulated proliferation of irradiated rodent bladder does not begin until approximately 3 months, coinciding with the onset of radiation-induced cell loss and denudation, and does not reach a maximum (cell turnover <6 days) until 6-9 months (Stewart, 1986;Stewart and Williams, 1991). Studies of Stewart et al showed that mouse bladder remains in a state of stimulated, rapid proliferation for up to 19 months after high single-dose irradiation, resulting in a hyperplastic but disorganised urothelium without replacement of properly differentiated, polyploid superficial cells (Stewart et al, 1980;Stewart, 1985).…”

Section: Bladdermentioning

confidence: 99%

“…Thrombotic lesions occur in both arterioles and larger arteries, and non-thrombotic intimal occlusive lesions also occur in large arteries. Tubular changes during this period include thickening of the basement membrane, cellular atrophy followed by necrosis, and interstitial fibrosis (Stewart and Williams, 1991;Robbins and Bonsib, 1995).…”

Section: Kidneysmentioning

confidence: 99%

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ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs — Threshold Doses for Tissue Reactions in a Radiation Protection Context

Stewart¹,

Akleyev²,

et al. 2012

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This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

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Section: Kidneysmentioning

confidence: 84%

Section: Kidneysmentioning

confidence: 99%

Section: Bladder and Uretersmentioning

confidence: 99%

Section: Bladdermentioning

confidence: 99%

Section: Kidneysmentioning

confidence: 99%

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ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs — Threshold Doses for Tissue Reactions in a Radiation Protection Context

Stewart¹,

Akleyev²,

et al. 2012

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Multiscale spatial relationship‐based model for predicting bladder wall dose in pelvic radiotherapy

Gao,

Ge,

Gao

et al. 2023

J Applied Clin Med Phys

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PurposeThis research aimed to develop a prediction model to assess bladder wall dosimetry during radiotherapy for patients with pelvic tumors, thereby facilitating the refinement and evaluation of radiotherapy treatment plans to mitigate bladder toxicity.MethodsRadiotherapy treatment plans of 49 rectal cancer patients and 45 gynecologic cancer patients were collected, and multiple linear regression analyses were used to generate prediction models for bladder wall dose parameters (, ). These models were based on the multiscale spatial relationship between the planning target volume (PTV) and the bladder or bladder wall. The proportion of bladder or bladder wall volume overlapped by the different distance expansions of the PTV was used as an indicator of the multiscale spatial relationship. The accuracy of these models was verified in a cohort of 12 new patients, with further refinement of radiotherapy treatment plans using the predicted values as optimization parameters. Model accuracy was assessed using root mean square error (RMSE) and mean percentage error (MPE).ResultsModels derived from individual disease data outperformed those derived from combined datasets. Predicted bladder wall dose parameters were accurate, with the majority of initial calculated values for new patients falling within the 95% confidence interval of the model predictions. There was a robust correlation between the predicted and actual dose metrics, with a correlation coefficient of 0.943. Using the predicted values to optimize treatment plans significantly reduced bladder wall dose (p0.001), with bladder wall and decreasing by 2.27±0.80 Gy (5.8%±1.8%) and 2.96±2.05 cm3 (7.9%±5.4%), respectively.ConclusionThe formulated prediction model provides a valuable tool for predicting and minimizing bladder wall dose and for optimizing and evaluating radiotherapy treatment plans for pelvic tumor patients. This approach holds promise for reducing bladder toxicity and potentially improving patient outcomes.

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Impact of Endogenous and Exogenous Factors on Radiation Sequelae

Baumann

1995

Late Sequelae in Oncology

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The Urinary Tract

Cited by 28 publications

References 107 publications

ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs — Threshold Doses for Tissue Reactions in a Radiation Protection Context

ICRP PUBLICATION 118: ICRP Statement on Tissue Reactions and Early and Late Effects of Radiation in Normal Tissues and Organs — Threshold Doses for Tissue Reactions in a Radiation Protection Context

Multiscale spatial relationship‐based model for predicting bladder wall dose in pelvic radiotherapy

Impact of Endogenous and Exogenous Factors on Radiation Sequelae

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