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Blood plasma used in healthcare is stored frozen for the longest shelf life, the blood plasma is then thawed before use.

This thesis describes the process of developing an improvement proposal replacing an accessory used in the medical device Rapid Plasma Thawing Device (RPTD), a product which with radio waves thaws frozen blood plasma. The accessory is called Antrad Thawing Cassette (ATC) and isthe device in which the blood plasma bag is placed when thawing.

The purpose of the assignment was to investigate how improvements to the current accessory in terms of cost, user-friendliness, capacity and functionality could increase the value of RPTD.

The assignment resulted in the improvement proposal Rapid Thawing Cassette (RTC) which is presented in two variants, one for folded blood plasma bags (RTC - Folded Bags) and one for unfolded bags (RTC - Ufolded Bags) which partly need shielding from the radio waves.

RTC replaces ATC and is considered to mean a marked improvement with regard to the compared product properties, especially the number of parts and the manufacturing cost, both of which are estimated to be reduced by 50%. Of all improvement goals, 85% were met with the two presented variants of RTC.

As a basis for the development of RTC, it was investigated how agitation and surrounding materials and geometries affect the temperature distribution in the blood plasma bag during the thawing process in a closed cavity with radio waves. Experiments performed showed the possibility of an alternative agitation method to the blood plasma during the thawing process. From the results it could be stated that the massage currently used for agitation is not the only method effective in the prevention of local overheating in the blood plasma.

From the literature examined, studies where radio waves were used for food processing could provide an understanding of how geometry and material choices affect the field distribution with radiowaves. It could also be stated that the impact on the radio wave field from surrounding materials is directly dependent on the dielectric material properties, also that material selection must be made with regard to the current dielectric load and how this is desired to be affected.

The work also investigated the challenges of achieving selective shielding against radio waves when thawing blood plasma in a closed cavity. The challenges can be categorized mechanically as well as physically. Purely mechanically, a shielding is possible as shown with "RTC - Unfolded Bags", the increased length of unfolded blood plasma bags, however, mainly means an increased volume of field-equalizing material around the blood plasma, this is awkward for the user to handle. Physically, challenges are also seen in ensuring that the properties of the blood plasma remain unaffected as conductive materials are introduced around the blood plasma bag and can potentially create harmful field concentrations.

The value of the presented work is seen to lie partly in the presented improvement proposal RTC, but also in partial results from performed experiments. The work described has contributed to Antrad Medical better understanding the limitations of ATC in RPTD, it also provides a concrete proposal on how this device can be changed for better profitability.