CTD

CTD may refer to:

Medicine

Science

Other

Chemotherapy regimen

A chemotherapy regimen is a regimen for chemotherapy defining the drugs to be used, their dosage, the frequency and duration of treatments and other considerations. In modern oncology, many regimens combine several chemotherapy drugs in combination chemotherapy. The majority of drugs used in cancer chemotherapy are cytostatic.

A fundamental philosophy of medical oncology, including combination chemotherapy, is that different drugs work through different mechanisms, and that the results of using multiple drugs will be synergistic to some extent. Because they have different dose-limiting adverse effects, they can be given together at full doses in chemotherapy regimens.

The first successful combination chemotherapy was MOPP introduced in 1963 for lymphomas.

The term "induction regimen" refers to a chemotherapy regimen used for the initial treatment of a disease. A "maintenance regimen" refers to the ongoing use of chemotherapy to reduce the chances of a cancer recurring or to prevent an existing cancer from continuing to grow.

CTD (instrument)

A CTD or Sonde is an oceanography instrument used to determine the conductivity, temperature, and depth of the ocean.

The CTD may be incorporated into an array of Niskin bottles referred to as a carousel or rosette. The sampling bottles close at predefined depths, triggered either manually or by a computer, and the water samples may subsequently be analyzed further for biological and chemical parameters.

The CTD may also be used for the calibration of sensors.

Measured properties

The instrument is a cluster of sensors which measure conductivity, temperature, and pressure. Sensors commonly scan at a rate of 24 Hz. Depth measurements are derived from measurement of hydrostatic pressure, and salinity is measured from electrical conductivity. Sensors are arranged inside a metal housing, the metal used for the housing determining the depth to which the CTD can be lowered. Titanium housings allow sampling to depths in excess of 10,000 metres (33,000 ft). Other sensors may be added to the cluster, including some that measure chemical or biological parameters, such as dissolved oxygen and chlorophyll fluorescence, the latter an indication of the concentration of microscopic photosynthetic organisms (phytoplankton) contained in the water.