Freehand technique

Fig. 7.13. A 1-year-old boy with a solid tumour arising from the adrenal gland. Biopsy was performed to confirm the diagnosis of neuroblastoma and to obtain specimen for genetic marker studies. The biopsy was done using freehand technique, the arrow delineates the hiopsy needle. S, spleen M, mass...

Magnetic field tracking is a relatively new tracked freehand technique that makes use of magnetic localizers to measure the transducer s position and angle in the space. At present it is considered the most successful tracked freehand technique. The system includes a magnetic field generator (transmitter), a miniature magnetic sensor (receiver) and a system control unit. 

Visceral Fetal Examinations. The examination of the abdominal and thoracic viscera of fetuses is performed either fresh without fixation ( Staples technique ) or after Bouin s fixation by making freehand razor blade sections ( Wilson s technique Wilson, 1965). Both techniques have advantages. The fresh examination technique, which may require less training for thorough proficiency, provides a more easily interpreted view of heart anomalies. The examination must be performed on the day the dam is terminated, however, so having a large number of litters to examine in one day requires that a large team of workers be committed to the task. 

With both techniques, the heads of one-half of the fetuses can be fixed in Bourn s fixative for subsequent freehand sectioning and examination. A common artifact induced by fixation in rabbit fetal heads is retinal folding. 

You may be saying to yourself, I can t draw. My drawings never look right Freehand technical sketching is an important skill. It is a simple one to learn with the right amount of practice. If you follow these easy techniques, you will soon be able to create freehand technical sketches. 

Using correct freehand technical sketching techniques, practice sketching horizontal lines. See Figure 4-21 for a practice example. 

Be sure to use correct sketching techniques as shown in Chapter 4, freehand technical sketching. 

Merrier L, Lango T, Lindseth F, Colbris DL. A review of cabbration techniques for freehand 3-D ultrasound systems. Ultrasound Med Biol 2005 31(2) 143-65. 

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