Automatic contour propagation using deformable image registration to determine delivered dose to spinal cord in head-and-neck cancer radiotherapy.

To determine delivered dose to the spinal cord, a technique has been developed to propagate manual contours from kilovoltage computed-tomography (kVCT) scans for treatment planning to megavoltage computed-tomography (MVCT) guidance scans. The technique uses the Elastix software to perform intensity-based deformable image registration of each kVCT scan to the associated MVCT scans. The registration transform is then applied to contours of the spinal cord drawn manually on the kVCT scan, to obtain contour positions on the MVCT scans. Different registration strategies have been investigated, with performance evaluated by comparing the resulting auto-contours with manual contours, drawn by oncologists. The comparison metrics include the conformity index (CI), and the distance between centres (DBC). With optimised registration, auto-contours generally agree well with manual contours. Considering all 30 MVCT scans for each of three patients, the median CI is [Formula: see text], and the median DBC is ([Formula: see text]) mm. An intra-observer comparison for the same scans gives a median CI of [Formula: see text] and a DBC of ([Formula: see text]) mm. Good levels of conformity are also obtained when auto-contours are compared with manual contours from one observer for a single MVCT scan for each of 30 patients, and when they are compared with manual contours from six observers for two MVCT scans for each of three patients. Using the auto-contours to estimate organ position at treatment time, a preliminary study of 33 patients who underwent radiotherapy for head-and-neck cancers indicates good agreement between planned and delivered dose to the spinal cord.

Delivered dose can be a better predictor of rectal toxicity than planned dose in prostate radiotherapy.

BACKGROUND AND PURPOSE: For the first time, delivered dose to the rectum has been calculated and accumulated throughout the course of prostate radiotherapy using megavoltage computed tomography (MVCT) image guidance scans. Dosimetric parameters were linked with toxicity to test the hypothesis that delivered dose is a stronger predictor of toxicity than planned dose. MATERIAL AND METHODS: Dose-surface maps (DSMs) of the rectal wall were automatically generated from daily MVCT scans for 109 patients within the VoxTox research programme. Accumulated-DSMs, representing total delivered dose, and planned-DSMs, from planning CT data, were parametrised using Equivalent Uniform Dose (EUD) and 'DSM dose-width', the lateral dimension of an ellipse fitted to a discrete isodose cluster. Associations with 6 toxicity endpoints were assessed using receiver operator characteristic curve analysis. RESULTS: For rectal bleeding, the area under the curve (AUC) was greater for accumulated dose than planned dose for DSM dose-widths up to 70Gy. Accumulated 65Gy DSM dose-width produced the strongest spatial correlation (AUC 0.664), while accumulated EUD generated the largest AUC overall (0.682). For proctitis, accumulated EUD was the only reportable predictor (AUC 0.673). Accumulated EUD was systematically lower than planned EUD. CONCLUSIONS: Dosimetric parameters extracted from accumulated DSMs have demonstrated stronger correlations with rectal bleeding and proctitis, than planned DSMs.

Image guidance protocols: balancing imaging parameters against scan time.

OBJECTIVE: Optimisation of imaging protocols is essential to maximise the use of image-guided radiotherapy. This article evaluates the time for daily online imaging with TomoTherapy® (Accuray®, Sunnyvale, CA), separating mechanical scan acquisition from radiographer-led image matching, to estimate the time required for a clinical research study (VoxTox). METHODS: Over 5 years, 18 533 treatments were recorded for 3 tumour sites of interest (prostate, head and neck and central nervous system). Data were collected for scan length, number of CT slices, slice thickness, scan acquisition time and image matching time. RESULTS: The proportion of coarse thickness scans increased over time, with a move of making coarse scans as the default. There was a strong correlation between scan time and scan length. Scan acquisition requires 40 s of processing time. For coarse scans, each additional centimetre requires 8 s for acquisition. Image matching takes approximately 1.5 times as long, so each additional centimetre needs 20 s extra in total. Modest changes to the imaging protocol have minimal impact over the course of the day. CONCLUSION: This work quantified the effect of changes to clinical protocols required for research. The results have been found to be reassuring in the busy National Institutes of Health department. ADVANCES IN KNOWLEDGE: This novel method of data collection and analysis provides evidence of the minimal impact of research on clinical turnover. Whilst the data relate specifically to TomoTherapy, some aspects may apply to other platforms in the future.

[Medical residency in hospital administration]. / Residência médica em administração hospitalar.

The increasing complexity of organized medical care requires that the field of hospital and health systems administration be included in medical curricula as a means of training professionals to do research, analyze and determine the community's health needs, obtain and efficiently use resources for meeting them, and promote activities that contribute to the community's wellbeing. With this end in view, the Polyclinic Hospital of the School of Medicine, University of São Paulo (Brasil) has instituted the Program of Advanced Studies in Hospital and Health Systems Administration (PROAHSA) which endeavors, during the medical residency, to complement the training of recently graduated physicians by providing the conditions they need to develop into health service administrators. In this two-year program, the resident physician acquires direct knowledge of the services rendered by the health organization, familiarizes himself with its purposes and problems, gains insight into its dynamics, and exercises his own initiative in establishing programs. The first level of the program is designed to give the resident a solid basic training; the second enables him to acquire specialized knowledge through in-depth study of the concepts, methods, and techniques of health services, administration and organization. Applying the concept of health services research, the program requires that the resident complement his biomedical and clinical research by studying different methods for the delivery of services, use of resources, and mobilization and use of manpower to organize hospital medical care.

Residência médica em administraçäo hospitalar / Medical residency in hospital administration

A crescente complexidade da assistência médica organizada trouxe o imperativo de incluir nos currículos de Medicina a área da Administraçäo de Hospitais e Sistemas de Saúde como meio de formar profissionais capazes de investigar, analisar e medir as necesssidades de saúde da comunidade, obter e utilizar eficientemente os recursos para satisfazê-las e promover atividades que contribuam para o seu bem-estar. Com vistas para esse objetivo, o Hospital das Clínicas da Faculdade de Medicina da Universidade de Säo Paulo (Brasil) instituiu o PROAHSA (Programa de Estudos Avançados em Administraçäo Hospitalar e Sistemas de Saúde), que procura, através da residência médica, complementar a formaçäo de médicos recém-diplomados, proporcionando-lhes condiçöes para se desenvolverem como administradores de serviços de saúde. Durante o programa, que se desenvolve em dois anos, o residente médico tem oportunidades para obter conhecimento direto dos serviços prestados pela organizaçäo de saúde, familiarizar-se com os seus objetivos e problemas e compreender a sua dinâmica, além de exercitar a iniciativa pessoal no desenvolvimento de programas. O primeiro nível do programa destina-se a dar ao residente uma sólida formaçäo básica; o segundo, a especializar os seus conhecimentos, aprofundando conceitos, métodos e técnicas utilizadas na administraçäo e organizaçäo de serviços de saúde. Aplicando o conceito de pesquisa em serviços de saúde, o programa requer do residente o desenvolvimento de estudos que complementam as pesquisas biomédicas e clínicas com modos alternativos de prestaçäo de serviços, utilizaçäo de recursos e mobilizaçäo e utilizaçäo de mäo-de-obra na organizaçäo do atendimento médico-hospitalar