The Swedish Two-County Trial is a randomized controlled study of invitation to breast cancer screening. It was initiated in late 1977. The follow-up to the end of 1998 provides results at approximately the twentieth anniversary of the trial. A significant decrease in breast cancer death among women invited to screening was published 7-8 years after randomization and at 20-year follow up there is a significant 32% reduction in mortality associated with invitation to screening. The advent of screen-film mammographic screening with the ability to detect potentially fatal tumors at an early stage provides an opportunity to study the natural history of breast cancer at an earlier phase in its development than was possible in the past. Our findings show that breast cancer is not a systemic disease at its inception, but is a progressive disease and its development can be arrested by screening. Detection of < 15 mm and lymph node negative invasive tumors will save lives and confer an opportunity for less radical treatment.

Blue grenadier, Macruronus novaezelandiae, or hoki as it is known in New Zealand, spawns at two distinct localities off New Zealand. Earlier research on morphometrics and on age and growth suggested that these spawning localities are used by two discrete stocks; however, the research was not conclusive. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used to analyse trace elements in otoliths from adult blue grenadier collected at the two spawning sites. Before analysis, portions of otoliths formed during juvenile and adult life were isolated and these segments were analysed separately. With a cross-validation procedure (jackknife), it was possible to classify correctly 100% of the samples in relation to age (juvenile v. adult). On the basis of the jackknifed discriminant functions, classifications of blue grenadier in relation to sex or capture locality were not significantly different from random. The results are not definitive in determining stock structure of New Zealand blue grenadier but do provide insight into the application of otolith trace element chemistry in studies of stock structure.

Optimisation must be carried out on all medical radiological units to ensure doses are as low as reasonably practicable, consistent with the intended purpose. To achieve this, population doses must be estimated and diagnostic reference levels (DRLs) set. For mammography examinations, mean glandular doses (MGDs) are calculated for this purpose. The average MGD per unit is compared to the national mammography DRL, which is applicable to compressed breast thicknesses (CBTs) of 50–60 mm for oblique (OB) views only and set using data from screening units. It is the purpose of this work to assess planar MGDs across Scotland and set DRLs based on data collected from all screening and symptomatic units across Scotland, considering craniocaudal (CC) and OB views and a wider range of CBTs. Data from the most recent dose audit (spanning 2015–2017) for 67 mammography x-ray units were collated and analysed (26 195 images). No large differences between MGD of CC and OB views were found when considering specific CBT ranges (median difference 2.6%). There was, however, a significant difference between screening and symptomatic data (19%). As expected, MGD increased with CBT and there were significant differences in MGD between manufacturers. From the data analysed, Scottish DRLs were set based on 95th percentile values for digital mammography units for three CBT ranges (30–49, 50–60 and 61–80 mm): 1.3, 1.8 and 2.6 mGy respectively. These values consider OB and CC views collectively. Fifth percentile values are quoted to highlight units at greater risk of insufficient image quality. These MGD values, together with image quality assessments, will facilitate optimisation across Scotland. Results show that use of different CBT ranges and inclusion of CC views increases the number of images included in dose audit data analysis from approximately 12%–92%, which is substantially more representative of the population.