Unique Considerations

Clinical staff taking part in diagnostic and interventional procedures using fluoroscopy wear protective aprons to shield internal tissues and organs in the torso from scattered x rays. Use of the measurements from monitoring devices worn outside and above protective aprons as the record of or E for these individuals results in significant overestimates of their actual risk. 

The current situation is exemplified by a study of clinical staff exposures in cardiac angiography at the Montreal Heart Institute (Renaud, 1992). Extensive measurements of staff exposures were made using thermoluminescent dosimeters (TLDs) for 15,000 procedures in three cardiac catheterization laboratories over a 5 y period (1984 to 1988). The TLDs were located under the protective apron at the waist and at the collar outside and above the apron. Readings were made at three-month intervals, with a minimum reportable value of 0.2 mSv. Average values (in mSv per y) for various groups of staff, based on measurements with TLDs worn at the collar, are given in Table 3.3. 

Physicians had the highest group average at 20 to 30 mSv per y, with the potential for some physicians, particularly those in training, to be assigned numerical values greater than the dose limit of 50 mSv per y if the results of the TLD on the collar are recorded as 

Other uses of fluoroscopy would have the potential for higher cumulative collar exposures. For example, abdominal interventional and angiography procedures typically use image intensifiers and x-ray field sizes which are larger than those used in a cardiac catheterization laboratory. Depending on the orientation of the primary beam, the scattered radiation from the patient may have greater intensity in these other clinical situations than in a cardiac catheterization laboratory. 

The Conference of Radiation Control Program Directors (CRCPD) recognized this need to convert personal monitor readings to He 

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Representative Method The best way to appreciate the importance of the theoretical and practical details discussed in the previous section is to carefully examine the procedure for a typical precipitation gravimetric method. Although each method has its own unique considerations, the determination of Mg + in water and waste-water by precipitating MgNH4P04 6H2O and isolating Mg2P20y provides an instructive example of a typical procedure. 

Although each acid-base titrimetric method has its own unique considerations, the following description of the determination of protein in bread provides an instructive example of a typical procedure. 

Representative Method Ion-selective electrodes find application in numerous quantitative analyses, each of which has its own unique considerations. The following procedure for the analysis of fluoride in toothpaste provides an instructive example. 

Representative Method Every controlled-potential or controlled-current coulo-metric method has its own unique considerations. Nevertheless, the following procedure for the determination of dichromate by a coulometric redox titration provides an instructive example. 

Pediatric Patients There are unique considerations in the treatment of HIV-infected children. Specific treatment guidelines exist,23 but a thorough review is outside the scope of this chapter. Most children acquire HIV infection through... 

US-EPA guidelines for endpoint-specific risk assessments contain guidance on exposure issues of relevance for the particular endpoint. For example, in the US-EPA Guidelines for Reproductive Toxicity Risk Assessment (US-EPA 1996) exposure issues important to reproductive toxicity risk assessment are addressed, and a number of unique considerations regarding the exposure assessment for reproductive toxicity are discussed. 

R4. Rimoin, D. L., Greenwald, S., et al, Unique considerations for genetic counseling in conununity-based carrier screening programs. Prog. Clin. Biol Res. 18, 297-304 (1977). 

The detection of land mines using THz spectroscopic imaging [40,51,52] has some unique considerations in terms of barrier materials. Currently, there are an estimated 100 million landmines buried worldwide. Anti-personnel mines are small devices and contain minimal amounts of metal. One potential advantage of THz technology is improved spatial resolution ( lmm) that should provide better discrimination of mines from harmless objects. 

Some unique considerations associated with flood-point definition apply to the grid charts only (10.8005 to 10.8108 only). These are described in Sec. 8.2.6 and should be consulted before interpolating flood data on those charts. 

General Biologic/Device Considerations The following is a list of potential unique considerations for assessing the safety of biologic-device combination products ... 

Another unique consideration is the prevention of nuclear criticality within the cells. In the dissolver and first cycle, criticality is prevented by the presence of the uranium-238, which absorbs neutrons. Later in the process, the plutonium is separated from the uranium. Criticality is prevented by proper design of the vessels and piping. This includes the cell floor and sumps, where materials would collect in case of leakage from the equipment. To prevent criticality, the vessels are limited in either diameter or thickness. Vessels and piping are placed in arrangements designed to avoid a critical array. 

Here are some things for women to think about in terms of dealing with blood pressure and preventing or treating hypertension. Women have unique considerations. 

Although the basic pathophysiology is similar for the various causes of hypovolemic shock, there are unique considerations relative to each. For example, whereas isolated head injuries associated with trauma typically do not result in substantial blood loss or shock, pelvic fractures may sequester several liters of blood as hematoma formation. Patients with traumatic or thermal injuries, as well as postoperative patients, may have substantial fluid accumulation in sites where it cannot be readily transferred back into blood vessels (i.e., third-spaced fluid) for maintaining pressure. With these types of injuries, prompt control of compressible bleeding sources with rapid patient transfer to the hospital for definitive treatment may preclude the cascade of events leading to shock. Indeed, with trauma patients, a scoop and run approach is used in most urban hospitals that places a priority on rapid transport to a hospital. ... 

Rimoin D.L., Greenwald S., Nathan T.J., Kaback M.M., Unique considerations for genetic counseling in community-based carrier screening programs. Progress in clinical and biological research 18 (1977) 297-304. 

Gravity flow is often used in bottom, reflux, side-draw, or feed lines. Unique considerations for gravity flow are described below, with specific reference to reflux lines. Considerations for gravity flow at other... 

For reasons described in the previous chapter, the discussions emphasize sieve and valve trays and exclude considerations unique to bubble-cap trays. Those unique considerations are detailed elsewhere (48, 86, 257). Nevertheless, several of the considerations discussed here also apply to several other tray t5q>es, including bubble-cap trays. 

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