Hyperthermia is a clinical cancer treatment method that relies on the principle of selectively heating tumour tissue with temperatures between 40 - 44 °C. For most head- and neck tumours deep hyperthermia treatment (DHT) is applied, in which electromagnetic energy is emitted to tumour tissue located ≥ 4cm below the skin surface. At the Erasmus MC Cancer Institute in Rotterdam, The Netherlands, electromagnetic energy is applied from a circular shaped applicator that is placed around the patient’s head or neck. A water bolus is placed between the applicator and the patient’s skin to act as a cooling agent to prevent skin burns and as a transferring agent to conduct the electromagnetic energy to the internal tumour tissue.

The goal of this master thesis was to redesign the water bolus that is currently applied in DHT at the Erasmus MC to increase patient- and operator comfort. For this purpose two main design challenges were addressed:

i) Design of an ergonomic fit for the water bolus
ii) Development of a method for uniform skin cooling and pressure control

For an optimal ergonomic fit of the water bolus, a 4D anthropometric model of head and neck was developed based on the 3D images of head and neck cancer patients that are treated at the Erasmus MC. Additionally, to secure appropriate cooling and pressure a honeycomb grid was developed. The pattern of the cavities in the grid guides circulating water through the entire volume to uniformly cool the skin. Furthermore, the grid itself provides shape stability to the water bolus, whereas the sides of the grid that are in contact with the patient’s skin provide flexibility. In addition, the water bolus was designed in a manner to enable an easy attachment to the deep DHT equipment by a sliding mechanism.

Humans wear helmets to protect the head from impact. However, covering part of the body influences the thermal balance due to restricting the heat loss capacity. This is especially the case for the head due of the lack of vasoconstriction response in the head’s skin. This project focussed on improving thermal comfort and perception when wearing a helmet in warm environments or during physical exercise. The main problem statement was: accumulation of heat underneath the helmet resulting in a rise in head skin temperature, decreased thermal comfort and exercise performance. There are five heat loss pathways in order for the human body to lose excess heat: conduction, radiation, and convection complemented with evaporation and respiration. Smith & Havenith (2011) identified the forehead, side of the head and neck as areas of high sweat rate, here evaporative heat loss has high potential for providing cooling. Fanger’s (1970) four conditions state that skin temperature and skin wettedness are the main factors determining a person’s whole body thermal comfort. The emphasis was placed on convective (airflow) and evaporative heat transfer as main cooling pathways. Also, active cooling was found to be necessary to provide enough cooling for the head according to Strijk’s (2008) model. The new Fantilated helmet features active cooling through ventilation, a pyramid structured padding embedded with micro channels and an absorbing biomaterial. The Fantilated helmet was prototyped to validate the design and the cooling principle. To test the active cooling system a thermal head manikin with thermal sensors on its surface was covered with a wet cloth to analyse the temperature changes on the head’s surface. The full set-up was placed on a scale to analyse the decrease in weight caused by evaporation. The active ventilation of the Fantilated helmet rendered positive results in terms of reducing the temperature and an increase in the evaporation rate. Both the decrease in weight and temperature suggest that the active cooling system of the Fantilated helmet will aid in improving thermal comfort. The Fantilated helmet that was used in this test was not optimal, also, the pyramid structured padding and the absorbing biomaterial were not present in the final prototype (and therefore not tested). Possibly, the final product/design could render even better results than the one used in this test. In conclusion, the Fantilated helmet is effective in decreasing the surface temperature of the head and improving the evaporation from the head’s surface. However, testing was done on a thermal head manikin and not on actual humans. Further development is recommended and testing on actual users is necessary in order to validate all aspects of the design.

This document covers the design process of a localized heating system suitable for retrofitting to buildings in the Netherlands

This report describes the development process of the pintracker, a product able to prevent and detect pin tract infections for external fixators.
The pintracker is designed in the context of the knee reviver, a medical device able to distract the knee joint. Knee joint distraction is a treatment method of osteoarthritis in the knee joint aiming at retention of the joint.
Knee joint distraction is an alternative treatment to total knee arthroplasty for young patients. Currently, total knee arthroplasty is the golden standard in treatment of osteoarthritis. For young osteoarthritis patients, implantation of knee prosthesis at young age, would implicate revision knee surgery at older age. Knee revision surgery is involved with complications, infections and low success rates. Knee joint distraction aims at retention of the knee joint to prevent knee revision surgery at older age.
The high infection rates involved with the use of external fixator pins is a significant limiting factor in knee joint distraction being adopting as viable treatment method for treating young arthritis patients.
Prior research within the UMC Groningen (Van der Borden et. al, 2004, 2005, 2007) showed that subjecting the bone pins of external fixators to an electric current reduces the development of pin tract infections at the pin sites significantly.
UMC Utrecht is continuing this research by applying the methods of infection prevention to the knee reviver. Pending animal studies should show the effect of applying a current to the bone pins of external fixators. The next step in this research is applying the methods in a product which can be used for infection prevention in human studies.
The result of this design process involves the design of a product which can be used for human trials. The device is able to store data on the resistance of the bone pins. Possibly, a correlation between infection development and resistance between the bone pins is found.
When present, the correlation can serve as means to detect infection development in an early stage. A product design is made of a product which can be produced in series. Detection of infection development is taken into account of a series product.
The product casing has been prototyped through iterative steps to increase the feasibility of the design.
In long term, the method can be applied to all external fixator pins. A conceptual design is proposed of a method to make the treatment method applicable to all external fixator pins. The added value of embedding an app with the pintracker has been described and the app is visualized.