bluuebunny/crossref_metadata_2025 huggingface dataset:
The genus Chaenothecopsis (Mycocaliciaceae) in Switzerland, and a key to the European species
Authors: GRONER Urs
Published: August 2006

Current knowledge about the non-lichenized genus Chaenothecopsis in Switzerland is reviewed. A characterization of the genus and a key to all accepted European taxa are presented, excluding the little known resinicolous species. The distribution of the 15 Chaenothecopsis species recorded in Switzerland is briefly summarized. Specimens in the herbaria belong mainly to C. pusilla, C. rubescens and C. viridialba; recent collections include rarer species such as C. hospitans, C. ochroleuca, C. retinens and C. tasmanica. It seems that many taxa occur predominantly in montane to subalpine forests in the Northern Prealps, although distributional data are still scarce.
I'm sorry I said that: apologies in young children's discourse
Authors: ELY RICHARD , GLEASON JEAN BERKO
Published: August 2006

We examined children's use of apology terms in parent–child discourse. Longitudinal data from 9 children (5 males, 4 females) between the ages of 1;2 and 6;1 were analysed. Before 2;0, the use of apology terms was rare. Thereafter, several developmental trends were noted including a decrease with age in directly elicited apologies and an increase in indirectly elicited apologies. With age children's apologies also became more elaborate. Children were exposed to apology terms primarily through apologies directed to them and, to a lesser degree, in talk about apologies. Our study documents young children's early mastery of an important pragmatic skill and identifies parents' role in its acquisition.
Individual differences in the influence of phonological characteristics on expressive vocabulary development by young children
Authors: MAEKAWA JUNKO , STORKEL HOLLY L.
Published: August 2006

The current study attempts to differentiate effects of phonotactic probability (i.e. the likelihood of occurrence of a sound sequence), neighbourhood density (i.e. the number of phonologically similar words), word frequency, and word length on expressive vocabulary development by young children. Naturalistic conversational samples for three children (age 1;4–3;1) were obtained from CHILDES. In a backward regression analysis, phonotactic probability, neighbourhood density, word frequency, and word length were entered as possible predictors of ages of first production of words for each child. Results showed that the factors affecting first production of words varied across children and across word types. Specifically, word length affected ages of first production for all three children, whereas the other three variables affected only one child each. The implications of these findings for models of expressive vocabulary development are discussed.
When answer-phone makes a difference in children's acquisition of English compounds
Authors: MURPHY VICTORIA A. , NICOLADIS ELENA
Published: August 2006

Over the course of acquiring deverbal compounds like truck driver, English-speaking children pass through a stage when they produce ungrammatical compounds like drive-truck. These errors have been attributed to canonical phrasal ordering (Clark, Hecht & Mulford, 1986). In this study, we compared British and Canadian children's compound production. Both dialects have the same phrasal ordering but some different lexical items (e.g. answer-phone exists only in British English). If influenced by these lexical differences, British children would produce more ungrammatical Verb–Object (VO) compounds in trying to produce the more complex deverbal (Object–Verb-er) than the Canadian children. 36 British children between the ages of 3;6 and 5;6 and 36 age-matched Canadian children were asked to produce novel compounds (like sun juggler). The British children produced more ungrammatical compounds and fewer grammatical compounds than the Canadian children. We argue that children's errors in deverbal compounds may be due in part to competing lexical structures.
Comparing different accounts of inversion errors in children's non-subject wh-questions: ‘What experimental data can tell us?’
Authors: AMBRIDGE BEN , ROWLAND CAROLINE F. , THEAKSTON ANNA L. , TOMASELLO MICHAEL
Published: August 2006

This study investigated different accounts of children's acquisition of non-subject wh-questions. Questions using each of 4 wh-words (what, who, how and why), and 3 auxiliaries (BE, DO and CAN) in 3sg and 3pl form were elicited from 28 children aged 3;6–4;6. Rates of non-inversion error (Who she is hitting?) were found not to differ by wh-word, auxiliary or number alone, but by lexical auxiliary subtype and by wh-word+lexical auxiliary combination. This finding counts against simple rule-based accounts of question acquisition that include no role for the lexical subtype of the auxiliary, and suggests that children may initially acquire wh-word+lexical auxiliary combinations from the input. For DO questions, auxiliary-doubling errors (What does she does like?) were also observed, although previous research has found that such errors are virtually non-existent for positive questions. Possible reasons for this discrepancy are discussed.
Effects of familiarity on mothers' talk about nouns and verbs
Authors: CLEAVE PATRICIA L. , KAY-RAINING BIRD ELIZABETH
Published: August 2006

Modifications mothers make when talking to young English-speaking children between the ages of 1;8 and 3;0 (average age=2;4) about words perceived to be familiar versus unfamiliar were investigated. Nineteen mothers and their children participated in two toy play tasks; one designed to elicit talk about familiar and unfamiliar animals and the other designed to elicit talk about familiar and unfamiliar actions. It was found that mothers' talk involving unfamiliar words differed from talk involving familiar words in a number of ways. Some modifications served to highlight the unfamiliar word which could assist in segmenting the unfamiliar word and mapping it to its referent. Compared to familiar nouns and verbs, unfamiliar nouns and verbs were produced more frequently in highly salient utterance positions and were paired more consistently with a clear nonverbal referent. Familiar nouns but, not verbs, were produced in longer utterances than unfamiliar nouns which could support the child's elaboration of the lexical representation of the familiar word.
Priming overgeneralizations in two- and four-year-old children
Authors: GERSHKOFF-STOWE LISA , CONNELL BRENDA , SMITH LINDA
Published: August 2006

Overgeneralization occurs when a child uses the wrong word to name an object and is often observed in the early stages of word learning. We develop a method to elicit overgeneralizations in the laboratory by priming children to say the names of objects perceptually similar to known and unknown target objects. Experiment 1 examined 18 two-year-old children's labelling of familiar and unfamiliar objects, using a name that was previously produced. Experiment 2 compared the labelling of 30 two-year-olds and 39 four-year-olds when presented with completely novel objects. The findings suggest that the retrieved word is a blend of previous activation from the prior retrieval and activation engendered by the similarity of the test object to instances of the target category. We put forward a theoretical account of overgeneralization based on current models of adult language processing. The account suggests a common mechanism of activation and retrieval, which may explain not only momentary lapses in the correct selection of words, but other types of naming errors traditionally thought to reflect differences in children's underlying category representations or, perhaps, gaps in their knowledge of words.
Distribution of putative adhesins in Shiga toxin-producingEscherichia coli(STEC) strains isolated from different sources in Chile
Authors: VIDAL M. , ESCOBAR P. , PRADO V. , HORMAZABAL J. C. , VIDAL R.
Published: August 2006

The distribution of three putative adhesin genes in 123 Shiga toxin-producing (STEC) strains was determined by PCR. The STEC strains were isolated from human patients (n=90) and food (n=33) and were characterized by serogroup, virulence markers (eae,stx1,stx2) and adherence factors (efa1,lpfAO157,saa) genes. Serogroups O157 (64·4%) and O26 (28·8%) were the most frequent among human strains and the majority (60·6%) of food strains were serologically non-typable. The adhesin genesefa1 (90%) andlpfAO157(73·3%) were the most common in humans strains andsaa(45·5%) in food strains. The presence of these genes in addition toeaein STEC from different sources may suggest a relevant role in their pathogenesis.
Henry Sidgwick's Practical Ethics: A Defense
Authors: SKELTON ANTHONY
Published: August 2006

Henry Sidgwick's Practical Ethics offers a novel approach to practical moral issues. In this article, I defend Sidgwick's approach against recent objections advanced by Sissela Bok, Karen Hanson, Michael S. Pritchard, and Michael Davis. In the first section, I provide some context within which to situate Sidgwick's view. In the second, I outline the main features of Sidgwick's methodology and the powerful rationale that lies behind it. I emphasize elements of the view that help to defend it, noting some affinities it has with those of the later Rawls. In the third section, I indicate how it promises to help alleviate some difficulties facing modern practical ethics. In the fourth, I respond to Bok's objections. I argue that her own work on practical ethics has some similarities to Sidgwick's which should make them friends, not enemies. In the fifth section, I respond to Hanson, Pritchard and Davis.
Compulsory Insurance without Paternalism
Authors: BOU-HABIB PAUL
Published: August 2006

This article examines how a just society must address the needs of its imprudent members. I defend compulsory insurance as an answer to this question. It has been assumed that compulsory insurance can only be justified on paternalistic grounds. I argue that this assumption is incorrect, and defend non-paternalistic compulsory insurance (NPCI). To display the merits of NPCI, I identify a trilemma that arises for views about how to address the needs of the imprudent, including libertarian and so-called ‘luck-egalitarian’ views. I then suggest that NPCI enables us to escape the trilemma.
Bistable nematic liquid crystal device with flexoelectric switching
Authors: CUMMINGS L. J. , RICHARDSON G.
Published: August 2006

Motivated generally by potential applications in the liquid crystal display industry [8,35], and specifically by recent experimental, theoretical and numerical work [6,7,13,14,21,25,30,31], we consider a thin film of nematic liquid crystal (NLC), sandwiched between two parallel plates. Under certain simplifying assumptions, laid out in £2, we find that for monostable surfaces (i.e. only a single preferred director anchoring angle at each surface), two optically-distinct, steady, stable (equal energy) configurations of the director are achievable, that is, a bistable device. Moreover, it is found that the stability of both of these steady states may be destroyed by the application of a sufficiently large electric field, and that switching between the two states is possible, via the flexoelectric effect. Such a phenomenon could be used in NLC display devices, to reduce power consumption drastically. Previous theoretical demonstrations of such (switchable) bistable devices have either relied on having bistable bounding surfaces, that is, surfaces at which there are two preferred director orientations at the surface [7,14]; on having special (nonplanar) surface morphology within the cell that allows for two stable states (the zenithal bistable device (ZBD) [4,21], or, in the case of the Nemoptic BiNem technology [11,19], on flow effects and a very carefully applied electric field to effect the switching.
Comparison of ensemble‐MOS methods in the Lorenz '96 setting
Authors: Wilks D. S.
Published: August 2006

A suite of methods that have been proposed for statistical post‐processing of ensemble forecasts based on historical verification data (i.e. ensemble‐MOS methods) are compared with each other, and with direct probability estimates using ensemble relative frequencies, in the idealised Lorenz '96 setting. The three most promising methods are logistic regressions predicting probabilities associated with selected quantiles, ensemble dressing (a kernel density estimation approach), and linear regressions with non‐constant prediction errors that depend on the ensemble variance. Copyright © 2006 John Wiley & Sons, Ltd.
Intercomparison of satellite‐based and model‐based rainfall analyses
Authors: Kästner Martina , Torricella Francesca , Davolio Silvio
Published: August 2006

Four satellite rain estimations based on microwave (MW), infrared (IR) or combined MW‐IR techniques are compared with the BOlogna Limited Area Model (BOLAM) rain forecast for a severe weather event (8–13 November 2001) over the western Mediterranean Sea.

Two of the investigated multi‐channel MW rainfall algorithms use data from the Tropical Rainfall Measuring Mission (TRMM). The Frequency Difference Algorithm relies on data from the TRMM Microwave Imager (TMI) and the other one combines data from the Precipitation Radar (PR) with those from the nine‐channel radiometer TMI, called PR Adjusted TMI Estimations of Rainfall (PATER) algorithm. The pure IR Rain Estimator uses geostationary IR METEOSAT data and the combined Naval Research Laboratory algorithm uses both MW data from low orbiting satellites and IR data from the geostationary orbit.

Validation results, computed over a common grid, which is independent of the different field of view sizes of the applied data sets, indicate that there is generally a better performance for heavy rain (>6 mm h−1) than for light rain (<1 mm h−1). Both MW algorithms perform rather similarly, although PATER shows some rain detection problems due to thick aerosol loads originating from the desert. The BOLAM model presents a good agreement with the MW and only a minor location error of a heavy rain area was detected. Both IR‐based algorithms have problems in identifying the correct rainy areas compared to MW. Overall, the results suggest that there are advantages in combining both techniques –the well‐known rain physics of the MW channels with the high temporal resolution of IR algorithms –to retrieve precipitation from satellite data. Copyright © 2006 John Wiley & Sons, Ltd.
An evaluation of three tangential breast irradiation techniques in Hong Kong
Authors: Law Maria Y.Y. , Cheung Fion W.K. , Wu Vincent W.C. , Tsang Venus W.C. , Kwan Rainnie W.Y. , Cheng Johnny Y.T. , Wong Fatson K.F.
Published: August 2006

Background and Purpose: Loco-regional radiotherapy after breast conserving surgery significantly reduces the risk of recurrence but may induce complications in the lungs. The complications are related to the lung volume irradiated and the lung dose delivered. The purpose of this study was to evaluate three tangential breast irradiation techniques i.e. conventional technique, gantry tilting technique and half-beam block technique in terms of the percentage of irradiated lung volume and high dose lung volume for patients of different sizes.

Materials and Method: Treatment planning of the three tangential breast irradiation techniques was performed using the CT scans of 20 patients with early-stage breast cancer after lumpectomy.

Results: When compared with conventional technique, both half beam block technique and gantry tilting technique irradiated a significantly smaller percentage of lung volume and delivered a smaller percentage of high dose (above 30 Gy) volume in the lung. Patients with large breasts had a significantly higher percentage of lung volume irradiated to above 30Gy than those patients with small and medium breasts. The combined effect of tangential separation and technique only produced significant effect on the percentage of total lung volume irradiated but not on the high dose volume.

Conclusions: Gantry tilting and half-beam block techniques can reduce a significant amount of lung volume and high dose lung volume. Half-beam block technique is recommended for small and medium breast size while for large breast size, gantry tilting technique is preferred.
Dose volume histogram analysis for organs at risk when using 6 external beam techniques for radical prostatic irradiation
Authors: Haycocks T. , Mui J. , Alasti H. , Catton C.
Published: August 2006

Ten patients with prostate cancer were each planned with 3 conventional and 3 conformal isocentric treatment techniques to compare the relative radiation doses to the bladder and rectal walls, and femoral head using dose volume histograms (DVH). The DVH were calculated for each organ and each technique, and the plans were ranked using the area under the curve method and also by the relative radiation dose given to specific normal tissue volumes.

The results show that for the planning target volume chosen, the 4 field non-coplanar technique delivers the least dose to the bladder, the 6 field coplanar technique delivers the least dose to the rectum and the 3 field oblique technique delivers the least dose to the femoral heads. The 4-field technique with no shielding contributes the most dose to the bladder and rectum and the 6 field coplanar technique contributes the most dose to the femoral heads.

No technique was shown to be optimal for all the organs at risk, but both the 6 field and 4 field non-coplanar field arrangements were shown to be superior techniques for minimising both the bladder and rectal dosage. The choice of technique will therefore depend on other factors such as the total prescribed dose, the ease of set-up and the ease of verification of isocentre reproducibility.
Dose analysis of three 3-D conformal radiotherapy techniques used in booster treatment of nasopharyngeal carcinoma
Authors: Wu Vincent W. C. , Chan Zeromon H. F. , Kung Shiris W. S. , Chau Celia K. F. , Fu Kenneth C. K. , Yip Kitty K. Y.
Published: August 2006

Three-dimensional conformal radiotherapy (3DCRT) has been introduced to treat nasopharyngeal carcinoma (NPC) in Hong Kong. Three more commonly used techniques, which are labelled as 3-field, 4-field and 6-field techniques, are currently employed as a booster treatment and no standard 3DCRT technique has yet been established. This study is aimed to evaluate and compare the dose distributions for the three common 3DCRT techniques so as to provide basis for the development of a routine protocol in future.

For each 3DCRT technique, eight patients with T3 tumours treated between 1997 to 1998 were recruited. Treatment planning was performed with the patients' CT images loaded into the 3-D treatment planning systems. The planning target volume (PTV) and eight organs at risk were delineated for dose assessment. Treatment plans were produced based on the criteria of the corresponding 3DCRT techniques. Dose volume histograms, 2-D and 3-D dose displays were used for dose evaluation.

All three techniques produced reasonable homogenous dose to the PTV. There was no significant difference in the mean doses of the PTV, spinal cord, lens, eyeball, temporal lobe and pituitary. The 3-field technique was superior in sparing the thyroid and optic nerve. The 6-field technique offered lower brain stem dose, and the 4-field technique was in between the two. The use of a vertex field slightly improved dose homogeneity of PTV and reduced the brain stem dose, but the doses to the optic nerve, thyroid, pituitary and temporal lobe were increased.
Randomized study comparing the impact of a simulator with CT option to diagnostic CT on workload and patients comfort
Authors: Bijdekerke P. , Vinh-Hung V. , Nys F. , Vandepoele E. , Van de Steene J. , D'Haese S. , Verellen D. , Storme G.
Published: August 2006

Purpose: A randomized study to investigate the routine use of a simulator-based CT (Sim-CT) for planning purposes.

Materials and methods: 24 patients accepted for pelvic radiotherapy were randomized to receive either a Sim-CT or a DCT planning CT scan. The execution time was measured for different steps in both procedures. A questionnaire was developed to gain information about the psychological status and physical comfort.

Results: The set-up (of hardware, software and patient) took significantly longer for the Sim-CT procedure (p<0.05). An average of 5.7 min was found in comparison with 3.2 min for the DCT group. A similar result (p<0.0005) was observed for the scan time (resp. 15.9 versus 5.1 min). However the total time of the procedure (including patient preparation) was significantly lower (p<0.005) for the Sim-CT group (resp. 21.6 versus 31.7 min). Physical comfort score showed that some patients experienced more discomfort during the Sim-CT procedure than during DCT.

Conclusions: The scan acquisition time and set-up time of Sim-CT procedure was significantly higher than DCT however the total time was less for Sim-CT group. The overall reduction in time with Sim-CT is counterbalanced by increased patient discomfort.
Complementary therapy use amongst oncology patients: what are the messages for Cancer Centre Services? Part 1
Authors: Killigrew S. G.
Published: August 2006

This study aims to examine two related contemporary issues in cancer care; why people with cancer use complementary therapies [CM] and what lessons there may be in this for Cancer Centre Services. The report will be presented in two parts. Part 1 is in the current issue and Part 2 will follow in the next. In Part 1 the main questions are identified and contextualised with the current literature on complementary therapy use. In Part 2 the method, results and analysis the survey and interviews will be explored. 148 patients attending the Leicestershire Cancer Centre returned questionnaires of whom 14 were interviewed in three separate focus groups. Patients from a cancer patient self help group were also interviewed as a fourth focus group. The qualitative data enabled a deeper analysis and evaluation of the quantitative data to be made. The discussion of the data places the main questions asked by the study into a wider context, including the Calman Hine Report and patient-centred care. The conclusions are that although a significant minority of patients [13%] were using CM at the time of the survey a significant majority of respondents [73%] identified a role for CM alongside conventional cancer treatment and 78% responded that staff at the Cancer Centre should be trained to advise them on the use of CM. The respondents acknowledged the resource and educational implications for Cancer Centres but stated that equal status should be given to care and cure in managing malignant disease. This in line with the Calman–Hine Report. Far greater numbers of patients may use CM if appropriate levels of resources and information were available. The findings indicate that integration of CM could assist in promoting future improvements in quality of survival and patient-centred care as identified by Calman–Hine and other recent health policy initiatives.
Errors from field placement and organ motion during conformal radiotherapy for prostate cancer
Authors: Wu J. , Haycocks T. , Alasti H. , Ottewell G. , Middlemiss N. , Abdolell M. , Warde P. , Toi A. , Catton C.
Published: August 2006

Purpose. To evaluate the effect of positioning errors from setup and from prostate motion during escalated dose conformal prostate irradiation for localised prostate cancer. Methods. Thirteen patients with localised prostate cancer had lateral portal films taken three times weekly during escalated dose conformal prostate radiotherapy. Field placement errors were measured by matching corresponding bony landmarks to the simulator film. Prostate motion at the base, mid-gland and apex was measured by imaging the displacement of 3 gold fiducial markers implanted into the prostate before therapy. From these measurements a planning target volume (PTV) was derived that allowed for both the prostate motion and field placement errors.

Results. The random isocentre positioning error was 2.2 mm (range 0.2–7.3 mm), and the mean systematic isocentre positioning error was 1.4 mm (range 0.2–3.3 mm).

Mean prostatic motion at the base was anterior 1.5 mm (SD 2.9 mm, range posterior 11.8 mm to anterior 16.8 mm), and superior 0.2 mm (SD 2.1 mm, range inferior 6.8 mm to superior 10.8 mm). At mid-gland it was anterior 0.6 mm (SD 2.4 mm, range posterior 7.2 mm to anterior 9.2 mm). At the apex it was posterior 0.3 mm (SD 2.1 mm, range posterior 7.9 mm to anterior 9.4 mm), and superior 0.5 mm (SD 2.1 mm, range inferior 6.7 mm to superior 10.2 mm).

The margin of PTV about the prostate needed to give a 99% probability of the GTV remaining within the 95% isodose line during the course of therapy for these patients is superior 5.8 mm, and inferior 5.6 mm. In the anterior and posterior direction, this margin is 7.2 mm at the base, 6.5 mm at the mid-gland and 6.0 mm at the apex.

Conclusions. Systematic setup errors were minimised by patient immobilisation and real-time corrections of setup errors. Prostate motion contributes the largest source of error, and this motion is greatest at the base of the gland compared to the apex. A non-uniform planning margin will improve target coverage while limiting normal tissue exposure. Fiducial markers implanted in the prostate improved quality assurance for radiation delivery by allowing confirmation of organ position within the treatment field over the course of therapy.
Intervention for acute radiotherapy induced skin reactions in cancer patients: the development of a clinical guideline recommended for use by the college of radiographers
Authors: Glean E. , Edwards S. , Faithfull S. , Meredith C. , Richards C , Smith M. , Colyer H.
Published: August 2006

The aim of this retrospective study is to develop an evidence-based approach to managing radiation induced skin reactions. A Clinical Guideline Development Group was established to undertake a systematic review of literature and a survey of cancer centres with the objectives of highlighting and recommending best practice. Thirty-one papers were reviewed using the United States Health Care Policy and Research and Scottish Intercollegiate Guidelines Network criteria and 42 United Kingdom Cancer Centres responded with a mix of guidelines and information about skin care assessment and advice. The evidence base for the findings is mainly levels II, III and IV.

Although perceived as common, the incidence of skin reactions has not been quantified. There is little evidence of consistent assessment of acute reactions and the survey data shows that the use of a scoring tool such as the Radiation Oncology Group criteria (RTOG/EORTC 1985) is rare. It also demonstrates that advice to patients is variable and sometimes contradictory. Appropriate and timely information is essential to relieve anxiety and reduce problems.

There appears to be a place for the use of creams in the management of early (RTOG/EORTC 0,1, 2a) skin reactions and in delaying the onset of subsequent skin breakdown, however this evidence is not clear and several of the studies identified some allergic reactions to creams. The intervention used varies between departments and individual patients and is ad hoc rather than based on firm evidence.

For reactions graded RTOG/EORTC 2b and 3, evidence from wound care literature suggests the use of hydrocolloids or hydrogels which are founded on moist wound healing principles. No evidence could be found to support the management of RTOG 4.

The study recommends the development of a clinical guideline encompassing factors affecting the onset of reactions, assessment and management principles, and patient information and makes suggestions for much needed further research.
An innovative approach to palliative care within a radiotherapy department
Authors: Blyth C. M. , Anderson J. , Hughson W. , Thomas A.
Published: August 2006

Palliative radiotherapy represents a substantial workload of a radiotherapy department. This paper provides an overview of a unique service designed to minimise the time between consent and delivery of radiotherapy for palliative patients. In common with other patient-focused care initiatives, this has been achieved by innovative and radically redesigned work practices. Through role development therapeutic radiographers can perform simple palliative treatments. Utilising dedicated equipment they cover all stages of the treatment process, from patient booking through to the end of treatment, providing seamless care for the patient and significant benefits for the department. Auditing the accuracy of simulator radiographs performed by radiographers alone tested the validity of providing simulation of palliative treatment without medical support. The results show 90% required no change with only 1% rejected due to radiographer misinterpretation. The remaining 9% required further information to be supplied by the medical staff. Evaluation of this service included patient and medical staff satisfaction surveys. The results of both were very positive with 100% of medical staff satisfied with the service and all patients rating the service from good to excellent. This project has more than achieved its targets.
Towards an evidence based treatment technique in prostate radiotherapy
Authors: Langmack K. , Routsis D.
Published: August 2006

There is a large evidence base around prostate cancer. Most of this concentrates on which stages of the disease to treat with which modality. The purpose of this study is to try and determine from the literature an evidence based radiotherapy treatment technique. The evidence is examined on prostate and patient motion, the effect of bladder and rectum filling, patient positioning and error detection with portal imaging. The technique derived is patient supine or prone with empty bladder and bowel. A simple leg immobilisation device is recommended, with set-up to couch height. The required margins are 13.2 mm laterally, 18 mm anterior-posteriorly and 21.3 mm cranio-caudally using a three-dimensional margin recipe. It is shown that an intensive portal imaging routine is required to demonstrate that systematic set-up errors are below 5 mm.
Improving the accuracy of localisation in the radiotherapy treatment of head and neck, and brain cancer: some initial findings
Authors: McJury M. J. , Nakielny R. , Levy D. , Lilley J. , Conway J. , Robinson M. H.
Published: August 2006

Aims: To investigate the impact on localisation of utilising contrast enhanced computed tomography (CT) scans and the formal input of a radiologist in the radiotherapy planning process.

Method: Ten head and neck / brain patients had pre- and post-contrast CT scans in the treatment position. Over several months, their unenhanced and enhanced scans were re-contoured by the original oncologist, and a radiologist. These new contours were compared to the original unenhanced contours and differences in contour volume, geographical position and tolerance doses on the associated PTVs were evaluated.

Results: The use of contrast lead to significant differences in the size of GTVs. Mean differences in GTVs of 32.8 % were significant at p=0.01. No significant impact on the position of the contour centre was noted. The impact of the radiologist lead to large differences in GTV (mean 20.5 %), but large SDs meant this result was not statistically significant. The contouring precision of the oncologist showed no significant difference for GTVs and PTVs.

Conclusions: The use of contrast when planning the radiotherapy treatment for head and neck / brain patients was found to lead to significant differences in GTV size, a lesser effect on PTV definition and little impact on the position of the contour centre. It may have important implications for multi-phase treatments where the GTV (rather than the PTV) is targeted for boost doses. Differences due to the input of a radiologist appear to be considerable and require further investigation when additional patient numbers have been acquired to improve precision.
Dose analysis of boost treatment to parapharyngeal space of nasopharyngeal carcinoma using three-dimensional conformal radiotherapy
Authors: Wu Vincent W C , Tsang Candy S C , Mak Freddy H K , Chan Joe C H , Leung Kenneth M W , Leung H W
Published: August 2006

Nasopharyngeal carcinoma (NPC) patients with parapharyngeal space (PPS) involvement are routinely given boost irradiation in Hong Kong. The current technique that employs a single field has many limitations in terms of dose distribution. This study is aimed to compare the dose distribution between the newly designed 3-dimensional conformal radiotherapy (3DCRT) and conventional techniques for the boost treatment of PPS so as to determine the more optimal treatment.

Fifteen NPC patients with unilateral PPS involvement were recruited. Their CT images were loaded into the FOCUS planning system for treatment planning. The planning target volume (PTV) and seven organs at risk (OARs) including the spinal cord, brain stem, optic chiasm, mandible, temporal lobe, temporo-mandibular (TM) joint and lens were outlined for dose assessment. The conventional and 3DCRT plans were then generated for each patient and the dose distributions were compared using dose parameters derived from the dose volume histograms (DVHs).

The 3DCRT technique provides better target coverage and significantly better dose to the planning target volume than the conventional technique. The 3DCRT treatment plans gives better sparing of the ipsilateral TM joints, mandible and lens, but it is less effective to spare spinal cord, brain stem, optic chiasm and temporal lobe. Nevertheless, the total doses to these OARs remain within the clinically defined thresholds and are clinically acceptable.
A comparison between two types of beam direction shell for the treatment of age related macular degeneration
Authors: Harris R. , Elder P. , Brock K. , Blackler N. , Glanfield J.
Published: August 2006

Background and Purpose: The aim of this study was to determine set-up accuracy when comparing an Orfit® thermoplastic shell to a traditional acetate shell for the treatment of patients with age related macular degeneration.

Method and Materials: 20 patients with age related macular degeneration were sequentially allocated to be positioned in either an Orfit® shell or a traditional acetate shell (ten patients in each group). On each day of treatment, radiographic portal imaging was used to ascertain accuracy by comparison with the CT image and verification radiograph.

Results: 140 portal images were assessed by three independent readers. Pearson Correlation and ANOVA statistics were performed on the data to assess differences between the two types of shell. Inter- and intraobserver variations were also analysed. Results, for both Orfit® and Acetate, revealed that over 95% of error movements were 2 mm or less.

Conclusions: The study indicates that both devices are of comparable accuracy and that the Orfit® shell is an acceptable method of immobilisation for the treatment of age related macular degeneration.
Issues surrounding the localisation and planning of brain and head/neck tumours
Authors: Blackler N
Published: August 2006

Technological improvements in imaging and increased sophistication in radiotherapy techniques are causing the necessity for the reassessment of treatments. In particular tumours of the brain and head and neck region are benefiting from improved localisation, planning and treatment. This paper presents an overview of these developments.
A pelvic positioning study comparing the set-up reproducibility of prone pelvic treatments for obese patients, with and without the use of a thermoplastic immobilisation shell
Authors: Harris R. , Daniel F. , Elder P. , Luffman C. , Bowen C. , Casebow M.
Published: August 2006

Background and purpose. The objective of this study was to assess set-up reproducibility of pelvic treatments for obese patients in the prone position, with and without the use of an immobilisation shell.

Method and materials. The patients were treated using a posterior open field and opposed lateral wedged fields for 20 fractions over four weeks. Ten fractions were set-up using a pelvic shell and ten fractions without. The patients were randomised into two groups, whose initial set-up was either with or without a shell. Portal images were obtained on 14 treatment fractions (7 for each set-up) and compared against initial simulator images to assess movement. For each fraction when portal imaging was scheduled the treatment radiographers also assessed the ease at which the patient could be positioned. The aim was to determine the correlation between good visual positioning to surface marks and accurate location of bony landmarks in portal imaging.

Results. Early results from this study highlighted large random positioning errors in the superior/inferior plane when patients were positioned in the pelvic shell. The study was therefore abandoned at patient number four.

Conclusion. The use of the pelvic shell was found to increase positioning errors in the longitudinal (superior-inferior) direction. Reasons for this observation are discussed and modifications to the shell design suggested. The study also highlighted that ease of patient positioning using surface marks is not a good guide to positional accuracy and emphasises the importance of regular on-set verification.
Intensity modulated radiation therapy (IMRT) in the radiotherapy treatment of colo-rectal cancer: the influence of profile smoothing on the efficiency of delivery
Authors: Laub W. , Yan D. , Robertson J. , Martinez A.
Published: August 2006

Small bowel toxicity due to radiotherapy treatment of rectal cancer is common. The potential use of intensity modulated radiation therapy (IMRT) to reduce the volume of small bowel irradiated during radiation therapy (RT) for cancer has previously been reported. However, IMRT treatment implementation is relatively difficult for these patients. The PTV is large and has a concave shape, with the small bowel in very close proximity. Therefore, the intensity profile calculated by an inverse planning engine could be highly modulated and complicated to deliver.

In this study, two methods were used to optimise IMRT plans for rectal cancer patients. Scatter contribution when backprojecting dose values to fluence values and a smoothing function were only implemented in the optimisation searching of one method. A common arrangement of five beams, each separated by equal gantry angle, was adopted. With both methods used, the dose coverage of the PTV was satisfactory. Small bowel irradiated to a dose of 95 % was reduced by about 70% as compared to a 3D conformal 3-field treatment technique. However, incorporation of scatter contribution and a smoothing function in the iteration of optimisation searching greatly reduced the degree of modulation in the two-dimensional intensity profiles. Instead of 120–160 step-and-shoot MLC segments only 30–60 segments were necessary to deliver the five intensity profiles. The number of monitor units per fraction was reduced accordingly to about one half. Therefore, by controlling the smoothness of the intensity profiles during optimisation, the produced IMRT plans could be delivered more efficiently. Moreover, the possibility to account for overlap of organs was found to be very valuable to avoid hot spots in these regions and to get the full DVHs of all organs at the same time.
A critical appraisal of the implementation of a ‘gap’ policy: five years experience in a department with one linear accelerator
Authors: Crane J.
Published: August 2006

In 1995, a meeting was arranged by the Radiation Oncology Committee of the British Institute of Radiology and the Royal College of Radiologists to look at the evidence of the impact of unscheduled gaps in radiotherapy on local tumour control, and to try to address some of the concerns that this raised. Following the meeting, guidelines were drawn up by a sub-committee of the Royal College of Radiologists to advise departments how to manage unscheduled interruptions or prolongation of radical courses of radiotherapy. One of their recommendations was that there should be regular audit of the outcome of the measures taken to avoid gaps in treatment. This paper presents how the guidelines were addressed in a department with one linac, together with the results of a 5-year audit.
Radiotherapy, physical activity and fatigue
Authors: Flinton D. M. , Pettet A. G.
Published: August 2006

Although it has long been known that fatigue is one of the more common side-effects accompanying radiotherapy treatment, little research into the topic has been done until recently. The article reviews the recent literature highlighting our lack of understanding of what fatigue is, its aetiology, its relationship to radiotherapy treatment and how best to deal with what some patients consider to be a major problem. Finally the paper looks at the evidence of the possible benefit that can be obtained through the use of exercise, a recommendation that is currently at odds with what most radiographers within Britain are advocating to patients.
“Living with radiotherapy”: the experiences of women with breast cancer
Authors: Johnson Jan
Published: August 2006

The research attempts to gain a greater understanding of the experience of radiotherapy from the viewpoint of the female patient with breast cancer. A qualitative, phenomenological approach was employed using semistructured interviews undertaken in the patient's home approximately two weeks after completion of their treatment course. Data analysis resulted in the description of five important categories of experience for the women. Discussion concludes that it is paramount for all health care professionals and therapy radiographers in particular to undertake and promote this type of research in order for them to establish and maintain a true sense of empathy and understanding with their patients. It also helps health care professionals maintain a sense of the importance of the ‘whole experience’ for those in their care. This type of enquiry provides a valuable and yet all too rare insight into aspects of attending for radiotherapy which would otherwise remain buried beneath the bustle of a busy radiotherapy department.

This article is an edited version of a Master's dissertation and as such can only convey the essence of the original work.
Part 1: An introduction to health care ethics
Authors: Smith G. E.
Published: August 2006

Health care ethics is a term that has come very much to the fore in the National Health Service during the past few years due to greater awareness of the subject and issues involved and challenging attitudes on the part of both health care professionals and patients. With advances in technology conflict of ethics has arisen, further increasing this subject's profile. This paper commences by defining some of the terms associated with health care ethics, followed by an explanation of two of the main underlying philosophical theories of medical ethics in modern health care practice.
CPD and portfolios: the process and product
Authors: Cooke K.
Published: August 2006

This review article aims to address the paucity of information regarding professional portfolio development for therapeutic radiographers. It will review briefly the current literature regarding continuous professional development (CPD) for therapeutic radiographers and add to the on going debate regarding the monitoring and enforcement of a mandatory CPD scheme. It will recapitulate the applications of professional development portfolios and equip therapeutic radiographers with the basic knowledge and skills to undertake the process of portfolio development, ultimately leading to a product that provides evidence of CPD.
A survey of in vivo diode dosimetry in the UK
Authors: Appleyard Robert
Published: August 2006

A clear rationale exists for routine in vivo dosimetry as part of an overall quality assurance (QA) programme within a radiotherapy department. A survey was undertaken in order to identify the extent of diode dosimetry practice within the UK.

Questionnaires were distributed to 57 radiotherapy physics departments in the UK in order to determine the extent of central axis diode dosimetry and the protocols implemented, the range of other in vivo measurements performed using diodes and the type of equipment used. Fifty-four responses were received. Eighteen departments undertook some form of central axis entrance dosimetry. Fifteen departments could be considered to be doing this routinely. Seven departments indicated planned future use. Six centres routinely undertook exit dosimetry with a further 3 indicating planned future use. Varied protocols for use were reported by those centres undertaking central axis dosimetry. Thirty-two respondents used a diode system for other forms of in vivo measurements with critical organ and TBI dosimetry being the most common. The vast majority used Scanditronix equipment.

Despite the distinct benefits of central axis diode dosimetry, this continues to be infrequently adopted as part of a departmental QA programme. However, an indication of a number of departments planning to implement such an approach is reassuring.
Spatial ability assessment: an aid to student selection for therapy radiography training
Authors: Waywell L. , Bogg J.
Published: August 2006

Therapy radiographers require the ability to perceive three-dimensional relationships, in order to position patients correctly for treatment. A test predicting this would therefore be useful during undergraduate selection. This study examines whether therapy radiographers have a greater spatial ability than the general population, and secondly the relationship between spatial and clinical ability.

A correlation design utilised 54 therapy radiographers. Each subject undertook 3 tests: 2 spatial ability tests; WAIS block test (WBT) and Lego block test (LBT), and a clinical set-up (CS). Results indicate that therapy radiographers have a significant higher level of spatial ability, p <0.001, than the general population in the 25–34 year age group. Pearsons correlation of WBT with LBT (r = 0.56, p < 0.0005) demonstrated concurrent validity of the new LBT.

The results suggest therapy radiographers have a higher degree of spatial ability than the general population. A test of spatial ability would therefore be of use to determine potential clinical competency during undergraduate selection. Whilst a potential useful instrument has been identified further research needs to be undertaken in this area as spatial ability is just one factor needed for clinical competence.
Part 2: Patients' rights
Authors: Smith G. E.
Published: August 2006

The issue of patients' rights has become an important part of modern health care practice due to patients being much more aware of what they can expect from health care professionals when they enter the health care environment. This paper commences by explaining what rights are, followed by a discussion of two fundamental rights issues considered important in the relationship between patients and health care professionals in order to ensure good health care practice.
The role of Digitally Reconstructed Radiographs in the verification process
Authors: Stanley N. S.
Published: August 2006

This article reviews the development and potential impact of Digitally Reconstructed Radiographs (DRR's) in the planning and verification of radiotherapy treatments. It explores the requirements for the creation of usable DRR's their integration into current verification methods and it highlights some of the factors that may influence the routine use of DRR's. Continuing developments in radiotherapy techniques demand increasingly accurate verification methods. DRR's provide an efficient and effective representation of planned treatments for comparison with both simulator and portal images, encompassing the digital imaging technology which is the future of radiotherapy treatment verification.