Patient doses in ct, dental cone beam ct and projection radiography in Finland, with emphasis on paediatric patients

Diagnostic radiology represents the largest man-made contribution to population radiation doses in Europe. To be able to keep the diagnostic benefit versus radiation risk ratio as high as possible, it is important to understand the quantitative relationship between the patient radiation dose and the various factors which affect the dose, such as the scan parameters, scan mode, and patient size. Paediatric patients have a higher probability for late radiation effects, since longer life expectancy is combined with the higher radiation sensitivity of the developing organs. The experience with particular paediatric examinations may be very limited and paediatric acquisition protocols may not be optimised. The purpose of this thesis was to enhance and compare different dosimetric protocols, to promote the establishment of the paediatric diagnostic reference levels (DRLs), and to provide new data on patient doses for optimisation purposes in computed tomography (with new applications for dental imaging) and in paediatric radiography. Large variations in radiation exposure in paediatric skull, sinus, chest, pelvic and abdominal radiography examinations were discovered in patient dose surveys. There were variations between different hospitals and examination rooms, between different sized patients, and between imaging techniques; emphasising the need for harmonisation of the examination protocols. For computed tomography, a correction coefficient, which takes individual patient size into account in patient dosimetry, was created. The presented patient size correction method can be used for both adult and paediatric purposes. Dental cone beam CT scanners provided adequate image quality for dentomaxillofacial examinations while delivering considerably smaller effective doses to patient compared to the multi slice CT. However, large dose differences between cone beam CT scanners were not explained by differences in image quality, which indicated the lack of optimisation. For paediatric radiography, a graphical method was created for setting the diagnostic reference levels in chest examinations, and the DRLs were given as a function of patient projection thickness. Paediatric DRLs were also given for sinus radiography. The detailed information about the patient data, exposure parameters and procedures provided tools for reducing the patient doses in paediatric radiography. The mean tissue doses presented for paediatric radiography enabled future risk assessments to be done. The calculated effective doses can be used for comparing different diagnostic procedures, as well as for comparing the use of similar technologies and procedures in different hospitals and countries.

Exploring Marketing in Micro Firms

Purpose - The purpose of the paper is to explore the practice of marketing in micro firms. Which are the challenges micro firms encounter and how do they handle them? Methodology - The research methodology is based on the theory-in-use approach (Zaltman, Heffring & LeMasters 1982) in order to inductively explore the practice of marketing in micro firms. The empirical findings rest on ten case studies, where data has been generated through repeated interactions with each case. Findings - The empirical findings show that micro firms handle their marketing challenges in a distinctive manner, by creatively using available resources and network relations. Marketing in micro firms is largely about a long-term, gradual development of a position on the market. This process we label germinal marketing. Two key dimensions of germinal marketing were identified: “earning your position” and “being your brand”. Research limitations and implications - The findings rest on an explorative study consisting of ten cases and the general applicability of the results need to be validated by further studies. These cases are however sufficient to illuminate the need for further research into the area. Value of the paper - The value of the paper is twofold. First, it expands the theory-in-use approach, and presents a research method for successful inductive empirical studies of small firm phenomena. Secondly, the paper widens our understanding of the marketing reality and practice of micro firms, identifying new dimensions of marketing and revealing the strategic implications of ordinary business activities.