PubMed · 1575080
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S H Taplin. Let guidelines be guidelines.. https://pubmed.ncbi.nlm.nih.gov/1575080/
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PURPOSE: Uncertainties in patient repositioning and organ motion are accounted for by defining a planning target volume (PTV). We make recommendations on issues not explicitly discussed in existing protocols for PTV design. METHODS: A quantity called "coverage" is defined to quantify how effectively a PTV encompasses the clinical target volume, and is applied to examine the impact of several factors. A stochastic simulation is used to determine the coverage required for a desirable balance between tumor control probability (TCP) and the irradiated volume. Using a sample anatomy, we assess the importance of the method used to add uncertainties, the shape of the uncertainty distribution, the effect of systematic uncertainties, and the use of nonuniform margins. Additionally, we examine the benefit of patient immobilization techniques. RESULTS: Our example indicates that 95% coverage is a reasonable goal for treatment planning. Using this as a comparison value, our example indicates quadrature addition of uncertainties predicts smaller margins (7 mm) than linear addition (11 mm), Gaussian distribution of uncertainties (7 mm) require the same margin as a uniform distribution (7 mm), systematic uncertainties have a small effect on TCP below a threshold value (4 mm), and nonuniform margins allow only a slight reduction of irradiated volume. CONCLUSION: We recommend that uncertainties should generally be added in quadrature, the exact shape of the uncertainty distribution is not critical, systematic uncertainties should be maintained below some threshold value, and nonuniform margins may be effective when uncertainties are anisotropic.
Many recent studies have demonstrated that routine examination of faeces for conventional enteric pathogens such as salmonella, shigella, campylobacter and parasites in patients who develop sporadic hospital-acquired diarrhoea is unnecessary and wasteful. In this paper the advantages and disadvantages of a restricted testing protocol in patients with hospital-acquired diarrhoea are reviewed. Practical issues for safe implementation of such a protocol are also discussed.
BACKGROUND: Cryptorchidism (CPT) is associated with gastroschisis, but the quoted incidence varies widely. The rarity of this combination of conditions has made it difficult to determine optimal clinical management. The aim of this study was to determine the incidence of CPT in gastroschisis and assess the outcome of different treatments. METHODS: Retrospective review of consecutive baby boys with gastroschisis treated during the 10-year period ending December 1997 was conducted. RESULTS: Fifty-one boys with gastroschisis were identified. Sixteen (31%) had CPT (9 left, 3 right, 4 bilateral). Ten of 20 undescended testes were extraabdominal ectopic (EAE). Of these, 2 had orchidopexy at the time of abdominal wall repair: 1 testis atrophied, and 1 is still undescended. Eight EAE testes were replaced into the abdomen at the time of repair. Of these, 3 descended to the scrotum and now are clinically normal, 3 later had orchidopexy and are clinically normal, and 2 had orchidectomy. Of the 10 testes that were CPT, but not EAE, 1 was absent, 7 descended without operative intervention, 1 had a good result after orchidopexy, and 1 was removed. CONCLUSIONS: These cases of gastroschisis had a 31% incidence of cryptorchidism. Because early conservative management led to normal descent in 10 of 17 testes, and a good result after later orchidopexy in a further 4, we recommend this treatment option.