Equipment for Patient Data Acquisition
W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald in Handbook of Radiotherapy Physics, 2021
The other main components of an MRI scanner are The refrigeration system used to maintain the cryogenic He in its liquid stateAn emergency system ensuring protection in case of magnet quench (loss of superconductivity with He turning suddenly into gas)An additional cooling system for the other electrical componentAn RF generator associated with appropriate electronics to transmit and receive the MR signalsVarious electronic and computerised devices to control the scanner and to process and display the information.
Hyperthermia in oncology and nontoxic integrative treatments
Clifford L. K. Pang, Kaiman Lee in Hyperthermia in Oncology, 2015
Refrigeration is divided into three stages: Overlow temperature, freezing, and thawing. To guarantee that cancer cells are destructed thoroughly, four factors play a decisive role, minimum temperature, freezing speed, freezing time, and freezing frequency. Within −10°C to −15°C, ice crystals begin to form in the cytoplasm, leading to the death of cell tissues. Based on this principle, the freezing effect depends on the freezing speed. When temperature drops, if the freezing speed is slow the ice first formed in the cell tissue clearances can absorb water from the cells. The dehydration in cells can obstruct freezing internally, so as to protect the cells from necrosis to some extent. Therefore, rapid freezing in cells is a key process of refrigeration. After the refrigeration process, thawing commences and it can damage the cell tissue. During the temperature rise to −20°C from −40°C, ice crystals can expand, resulting in the busting of the ice balls formed during refrigeration, which can cause the same high destruction as the refrigeration process itself. Multiple freezing–thawing cycles can thus increase the destructive effect of cryosurgery.
Fixation and Tissue Pretreatment
Lars-Inge Larsson in Immunocytochemistry: Theory and Practice, 2020
Thus, an intermedium that does not boil at as low a temperature as liquid nitrogen is desirable to use. Freon-22® is freely available in pressure bottles from several refrigeration firms and is preferred. When cooled by liquid nitrogen, the Freon® solidifies. It is convenient to use a metallic cup suspended in a liquid nitrogen bath to collect the Freon.® The cup is filled and then taken up from the nitrogen bath (Figure 10). Upon melting of the Freon® ice, specimens embedded in O.C.T. compound and supported on stiff paper are immersed and frozen in the Freon.® The frozen specimens (after 10 to 20 sec of freezing) are then quickly transferred to liquid nitrogen. They can be stored in this or in a − 80 to − 70°C freezer until required for sectioning. Intermedia other than Freon® may be used (propane-propylene or isopentane). Due care should be excercised when employing such intermedia, as propane-propylene mixtures in particular may be explosive when mixed with nitrogen!
Efficacy of alternative cooling devices used for insulin storage without refrigeration under hot-humid environment
Published in Annals of Medicine, 2022
Supang Taerahkun, Chutintorn Sriphrapradang
Without mechanical refrigeration, evaporative cooling is a well-known and efficient system for maintaining temperature for short-term storage of perishables [13]. The traditional evaporative cooler consists of a porous outer clay pot lined with water or wet sand containing an inner pot within which the food is placed. The device cools as the water evaporates and draws the heat from the inner pot. These coolers were proved for short-term insulin storage [14–16]. The evaporative cooling system does not require electricity and can be easily constructed using locally available materials with unskilled labour. However, high ambient humidity condition decreases the cooling capacity of the evaporative cooler since the water cannot evaporate well under these conditions. To date, there have been few studies on the cooling efficacy of insulin storage devices, which were performed in desert climates countries [15,16]. Noteworthy, there is no data in tropical regions, such as Southeast Asia countries. Therefore, we sought to develop insulin storage devices that could be easily reproducible using locally available materials at minimal cost in Thailand.
Recent advances in freeze-drying: variables, cycle optimization, and innovative techniques
Published in Pharmaceutical Development and Technology, 2022
Mohammed M. Mehanna, Kawthar K. Abla
The conventional freeze-dryer consists of five main components: refrigerator unit, vacuum unit, control unit, product chamber or manifold, and the condenser. The refrigeration is employed to cool both; the shelves within the product chamber and to cool the condenser. The vacuum unit provides pressure for conducting the drying stages. The system is made up of a separate vacuum pump attached to the chamber and connected to an airtight condenser. The control system contains temperature and pressure sensors attaining to set up these critical values as required. The product chamber of the freeze-dryer is either a manifold with attached flasks or a chamber containing shelves where the product is placed and dried. The condenser aims to collect the vapor released by ice within the product, where the vapor condensed before returning into ice within the condenser itself. The accumulated ice is removed manually at the end of the drying stage. The condenser temperature is dictated by Tp and the product freezing point. The refrigeration system should keep the temperature of the condenser below the product temperature. Typically, the temperature of the condenser in the commercial freeze-dryer is about −65 °C (; Bisht and Iqbal 2018; Garcia-Amezquita et al. 2015).
Spaceflight medical countermeasures: a strategic approach for mitigating effects from solar particle events
Published in International Journal of Radiation Biology, 2021
Filgrastim, peg-filgrastim and sargramostim are all viable candidates for treating H-ARS if necessary. It is recommended that NASA select one of these drugs and transition it to operations for inclusion in the medical kit in support of long duration missions. When selecting the drug, NASA should take into account storage, ease of administration, shelf-life and stability. A comparison of these properties for each H-ARS candidate is outlined in Table 2. Storage will be a critical factor since refrigeration may be a challenge particularly in early missions. While lyophilized drugs offer weight and storage savings, reconstitution may be a challenge in spaceflight predominantly due to bubble formation. This may warrant a pilot study on the ISS to test whether bubble formation would be an issue if lyophilized drugs are selected for the medical kit in support of a mission. Ease of administration is important in addition to shelf life and stability of the MCM. Given the length of the proposed missions and the environment, a shelf-life of more than three years may be required to ensure the MCM maintains efficacy and does not degrade into toxic byproducts over the duration of the mission.
Related Knowledge Centers
- Cryogenics
- Laser Cooling
- Refrigerator
- Curing
- Salting
- Food Drying
- Root Cellar
- Cold Chain
- Refrigerator Car
- Refrigerator Truck