FAQ

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What is aging of X]ray unit?

A procedure to be followed everyday before using the equipment. Aging may extend the service life or the X-ray tube.

If the maximum service voltage of the tube is 140kv, first apply voltage from 60kv to 100kv at l0kvintervals, then to l40kv at 5kv intervals (200mA. 0.04sec constant).

More simply when applying voltage to the tube, raise the voltage from low to higher level gradually.

Don't start taking radiographs outright with high voltage.

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Can't determine the right side of exposed X-ray photographs

Radiographs usually depict the affected part. The heart is located at the left-hand part of the body and the diaphragm, lower to the left. But hands and feet can be confusing sometimes the left. But hands and f‚„et can be confusing sometimes.

Your judgement changes depending on the radiographic direction or A to P or P to A.

Exposed film is always marked with the type name of the sensitized paper.

If such a type name (B-2, Hi-screen, etc.) can be read normally, the film is radiographed in P-A direction and if in reverse, in A-P direction.

Remember the direction or radiography. If it was in P-A direction, set the film (to view box) so that the type name can be read normally. In this case, standing in front of the film, the left-hand side represents the right-hand portion of the subject. In the case of an A-P radiograph, set the film to view box so that the type name reads in reverse, The left-hand side of the film represents right-hand portion of the subject.

The type name is baked into the dark section on the film which makes it hard to recognize, Check the type name in the light (sunlight if the weather is fine.)

Remember to mark right or left on the film during radiography.

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Chest radiographs have different density
on the left- and right-hand sides.
What causes this?

The ‚w-ray tube is twisted. This stands out particularly during chest radiography.

(How to check) Hold the tube close to the cassette or Bucky (radiographic device) and turn the radiation field lamp on.@@@@@@

Mark the cassette or Bucky to indicate the center or the center line (cross hairs) of the radiation field. Shift the tube parallel.

If the center of the radiation field dose not shift to the left or right, the tube is not twisted. If the center shifts, the tube is twisted, which should be corrected.

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Streaks in the X-ray photograph hamper reading.
Streaks appear basically because the Bucky grids are not moving.

The most likely cause is selection error of the tube. Normally, tube selection is available for Bucky and non-Bucky. (Recently, microfine grids have become available which produce no conspicuous streaks.) A similar phenomenon appears with a faulty Buckyfs device.

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X-ray photograph contrast is too strong/weak.

This is attributable to the automatic developing machine unless radiographic conditions are changed.

High developing temperature (high contrast and fogging).

Low developing temperature (low contrast).

If this phenomenon appears upon changing to a new film or radiographic conditions, these changes are the cause of the contrast problem.

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X-ray photograph seems to be fogged.

Developing temperature is too high.

Developing solution is fatigued.

Film has expired.

Wrong type of safety lamp is used in the darkroom (safety lamp for orth or regular type). Radiographic conditions are too high. Scattered line fogging is present (use Bucky Table).

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How can we detect fatigue in processing liquid of an automatic developing machine?

View the portion without film density (transparent portion). See if this portion is fogged or not. If fogged, the solution is fatigued (the same phenomenon occurs if the developing temperature is too high).

High density portion does not become black as usual. It has turned out to be a photograph without contrast.

The best way is to photograph a picture when the solution is fresh, and compare it (How to control an automatic developing machine)

Keep periodical maintenance of developing solution (for prevention or fatigue).

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What are the selection standards or films and screens?

Select the orth system when the system relative sensitivity reaches 200 and over (film and screen combined sensitivity).

Excessively high level of sensitivity causes degradation of picture quality (HR-S + HR-4 and other combination available from Fuji, Konica and Kodak).

Orth type provides good picture quality (sharpness, graininess). But the shortcoming is the high price of the screen. A variety of films are available depending on the objectives of radiography and inspection (chest system is particularly recommended).

Care should be taken when mixing orth and regular types (for both film and screen). There is no advantage, since it exposes subjects to higher radiation.

Application of orth system is over 70% countrywide (while only about 50% of the clinics in remote areas use it).

How to separate orth type from regular type

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Is there any simple way to manage automatic developing machines?

Use an aluminum step to measure the developing temperature and take radiograph of the aluminum step under identical condition for knee joint radiography. Record the developing temperature, radiography distance, tube voltage, current, exposure time and cassette used. Never change them.

(For example, 50kV, l00mA, 0.2sec, 100cm, 35Ž, etc.)

Draw the range to about the width of the aluminum step (as transparent portions where no X-rays are radiated to are also needed).

Develop the exposed film and keep it as the standard for future control (use it as the reference density film).

After a week or two, photograph the aluminum step under the initial conditions and develop it. Compare the newly developed film with the standard reference film. If the density, fogging and contrast of the step remain unchanged, the developing solution may continue to be used as it is not fatigued. If any change is noted, photograph the aluminum step again for similar comparison@(to check for errors in the photograph and development). If the same change is noted, it can be concluded that the developing solution is fatigued or the automatic developing machine is faulty (defective developing temperature, etc.). In the case of a faulty developing machine, however, the change occurs suddenly (normal radiograph was made on the preceding day). Solution fatigue appears gradually, making it difficult to tell unless compared with the reference film. If, upon comparison, it is found that the density of the step is not blackened (density of the 5th level of control is identical to the 8th level of the reference film for comparison), fogging is present, or the contrast has become lower, then the solution is fatigued. Replace it with fresh solution.

After replacing the solution, photograph the aluminum step and compare with the control film. In no change is noticed, it is OK. If changes persist, the automatic developing machine or the X-ray unit is probably faulty. A faulty developing machine can be checked easily as already mentioned, but it is difficult to determine failure of the X-ray unit (as change in output appears gradually). If possible, it is recommended to photograph the same subject with another X-ray unit. If one of the units produces normal density while the other produces a different outcome, the latter unit can be determined to be faulty.

As thus far described, the density of the automatic developing machine can be controlled by photographing and developing the aluminum step once every week or two. For example, if any change is noticed after four weeks the developing solution of this machine can be judged as having a life of four weeks. Accordingly, from the next time, the aluminum step should be photographed once every four weeks. Since the number of days it takes for the solution to reach fatigue condition changes depending on environmental changes (summer or winter) and the number of films developed, density control should be conducted once every two weeks.

Cassette and aluminum step

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How to tell orth type from regular type?

The only method of telling film types apart is by checking the brand.

To check the screen, irradiate the cassette in open condition with X-rays (open the cassette to allow the screen to be seen). Note that the X-rays should be irradiated in a darkened room or emission may not be visible. Irradiation may be under simple abdomen conditions. If emission is in green, the screen is of the orth type. If blue, it is the regular type.

Always use film matched to a particular screen type.

Most or fluoroscopic screens for the stomach are of the orth type (70% according to a survey conducted by Tochigi Prefecture).

If the type of film/screen cannot be determined at all, please E-mail the address below stating the brand. We will contact you after checking thc type.
E-mail address:
hosoudan@jichi.ac.jp

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How should we use grids (scattered line removing plate)?

Generally, the scattered line removing plate is called the grid. Using the grid in motion is called Buckyfs method (Buckyfs radiographic device), using it stationary is called the gBucky Tableh method. The grid is not applied to the upper limbs distal from the shoulder (the humerus, elbow, forearm, hand joint, etc,). Nor to the lower limbs distal from the knee joint (lower leg, foot joint, tarsal bone, etc.). Nor to gsoft tissueh radiography. It may be used for the shoulder and knee (muscular shoulder and thick knee, etc.). A tube voltage of 60kv and over should be used.

Caution shall be given to the following points:

Service range (concentration range and inapplicable range); checking on the X-ray tube focal point to the left/right to be matched to the center line); X-ray application in oblique direction (incidence of the X-ray not to be in oblique direction), and in reversal (may require no explanation).

Care is also needed with respect to the grid ratios (5:1/6:l/8:1/10:1, etc.) and appropriate tube voltage. Application@error may reduce the scattered radiation reduction effect or increase radiation exposure. Generally, a tube voltage of 60kv should be used for a grid ratio of 6:1 or 80kv for 8:1. Unless a high voltage (l20kv) is used for a grid ratio of 6:1, for example, the applied voltage does not require too much attention, however.

Grids

Wall type Bucky's device

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What is a photo-timer (automatic exposure unit)?

A device for blackening the subject image to the prescribed level by automatic camera mechanism.

This device is attached to most of radiographic equipment (called AEC, etc.).

Installed to a radiographic bed or wall type Bucky, radiographs can be taken without having a to adjust radiographic conditions (useful for chest, abdomen and spinal radiography).

For application, care is required in placing the subject within the light-receiving plane. The shape and position of the light-receiving plane (also called light collecting field) differ from manufacturer to manufacturer (trapezoidal, circular, butterfly shape, 3-point type, etc.), which should be noted. Exposure time should be set a little longer (than for automatic radiography, otherwise exposure will stop at the set time, producing under-exposed photographs).

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We often allow expired films to be used. What measures can be taken?

Film that has already expired will become foggy and lose contrast.

Purchase 50-film packages instead of 100-film packages.

Substitute rarely used size (ll x l4 in., 8 x 10 in.,etc.) with other sizes Use the same film for 10 x 12 in. size@as for transmission radiography. (since the transmission units often use orth type screens, the cassette must be arranged with the orth type screen).

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Radiographs of senior persons and/or children are blurred, How can we take good radiographs?

Radiographs of patients who do not hold their breath often become blurred. To prevent this, short-time radiographs are desirable (blurred photographs are meaningless).

For short-time radiography, the best method is to use a larger tube ceditions that match the particular facilities. For@example, radiography at l00mA for 0.4sec can be changed to 200mA for 0.2sec or to 400mA for 0.1sec with the unit permitting.

Remember that if the product of the current and exposure time is the same (current x time), subject can be radiographed in the same density.

More expansively, change the tube voltage from 70kv to 80kv. Then the exposure time can be reduced to a half. Another way is to reduce the radiographic distance. (If the distance is reduced from 200cm to 100cm according to the inverse-square law, the exposure time can be reduced to one fourth.) Besides, raising the sensitivity of sensitized material system is another way to shorten the exposure time.

Lastly, if a system of 70kv -100mA at 0.4sec with a distance of 200cm and a sensitivity of 100 can be changed to a system of 80kv-200mA at 0.012sec with a distance of 100cm and a sensitivity of 200, subject can be radiographed in 1/32 of exposure time. (The optimal combination should be discretely reviewed for actual implementation.)

Another method is to change the tube voltage (according to a conversion table).

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Don't know radiographic conditions for subjects having other than standard bodies (including senior persons and children)?

Radiographic conditions differ by the unit, sensitized material, automatic developing machine, etc. Conditions described by manufacturers only contain units for general application. The best way to obtain the radiographic conditions is to generate, on site, the list of radiographic conditions that are matched to the particular facilities. But remember that the list of conditions@is for standard bodies. For example it is recommended that the patientfs figure be compared with onefs own figure and that gtwo-tap longer exposure be given as the patient is heavier.h In the case of children, take radiographs by comparing the child's section with a grownup's section having equivalent area (for example, a child's knee has approximately the same area as a grownupfs elbow). The abdomen in the prone position may be taken by lowering the condition for the lumbar vertebra slightly (by two taps of the timer). The pelvis and coxa may be taken under the same conditions. By following this way of thinking, radiographic conditions can be determined without any trouble.

For patients that differ greatly from the standard figure, resolute upward or downward correction of the radiographical conditions is required. Generally speaking, correction often fails because it falls short of the required up or down correction. To change the radiographical conditions, it is better to change the tube voltage (by approx. l0kv). For normal subjects, change the timer condition to obtain more stable radiographical results. (Changing the tube voltage causes the X-ray energy to change because of differences in the penetrability or the X-rays generated. Proportional to 3.5 to the 6th power of the tube voltage; inversely proportional to the second power of the radiographic distance; and the tube current and exposure time are simply proportional.)

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Want to create a correct list of radiographical conditions?

The list of rudiographical conditions is intended for single-phase, full-wave rectification device use. It is not applicable as is to advanced type inverters or 3-phase units, for which care should be taken.

If a radiograph taken of a knee for example, using this list of conditions produces an over-exposed (black) picture, lower all the conditions equally (lower only exposure time). If the picture is under-exposed (white), raise all the conditions, For example, if a blackened picture resulted when taken under certain conditions, better conditions may be possible by lowering the time by 2taps. Thereafter, use a11 the conditions by lowering them by 2-tap time only.

Moreover, radiographical conditions change depending on the equipment, film, sensitized paper and automatic developing machine used.

Please note that we are not responsible for any equipment faults that may result from using this 1ist of conditions. So, be sure to take the performance of the equipment in account before using the table of conditions.

(Refer to the list of conditions for single-phase, full-wave, radiographic conditions.)

If the tube voltage is too low, correct the respective facilities (by referring to the conversion table).

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What is FCR (Fuji Computed Radiography)?

FCR has the following advantages. By digitalizing image information, radiographs can be taken even under approximate conditions; reduced radiation exposure; reduction of re-radiographing; improved diagnostic information over a wide latitude, etc.

It is the optimal system for facilities having no X-ray technician, although it does involve an extra cost burden on introduction. (Recently, a similar system was introduced by Kodak.)

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