Lateral Knee

March 7th, 2010 by RadiologyTech No comments »

Lateral knee

IR size: 10×12 inches

Shielding: Lead shield around waist

Patient Position: Have patient in lateral recumbent position with affected side down.

Part Position: Adjust body and leg until knee is in a true lateral. Flex knee 20-30 degrees

Central Ray: Center 1 inch distal to medial epicondyle. Also angle the tube 5-7 degrees cephalic.

SID: 40 inches

Collimation: Collimate to lateral skin margins

Respiration: patient does not hold respiration.

Distortion Test

March 2nd, 2010 by RadiologyTech No comments »

Distortion

1)      T or F: In all instances reduced magnification increases the resolution of recorded detail.

2)      _________ is a misrepresentation in size or shape of the part being imaged.

3)      What are the two influencing factors in size distortion?

4)      Size distortion can be calculated with the formula M=SID/SOD.  What percentage change would there be with an SID of 72 inches and an OID of 6 inches?

5)      After you have the magnification factor and the image size you can figure the actual object size using O=I/M.  If an image measured 10” and had the magnification factor of the problem above what would be the actual object size?

6)      Changes in the tube angle cause what type of shape distortion?

7)      T or F:  Improper tube centering has no effect on shape distortion.

 

 

 

 

 

Answers

1)      True

2)      Distortion

3)      SID, OID

4)      9% or 1.09 increase

5)      9.17”

6)      Elongation

7)      False, tube centering plays a huge roll in how the body part is represented

Recorded Detail Test

March 2nd, 2010 by RadiologyTech No comments »

Recorded Detail Quiz

1)      The primary film/screen unit of resolution is ______ _____ ___ ___________.

2)      In digital imaging spatial resolution is determined by 3 things; matrix size, pixel size, and _______ _____ _____ _____.

3)      T or F: Spatial frequency is one way to measure recorded detail in a digital system.  A shorter wavelength is a high resolution as opposed to a long wavelength which is low resolution.

4)      _______ _______ _______ is another way to measure resolution it measures the information lost between the patient and the image receptor.  A perfect transmission of information would be 1.0

5)      T or F: Recorded detail is one of 2 photographic properties of image quality.

6)      ______ is background information that is picked up by the image receptor

7)      _________ or unsharpness around the image can be mathematically calculated using what formula?

8)      ________ is the best way to prevent voluntary motion.

9)      ________ is the best way to prevent involuntary motion.

10)   In this problem I will give you a parameter and you must say when it increases does it increase or decrease spatial resolution

A) SID

B) OID

C) FSS

Film Screen

                1) Phosphor size

                2) Layer thickness

                3) Packing density

 

 

 

Answers

1)      Line pairs per millimeter

2)      Gray scale bit depth

3)      True

4)      Modulation Transfer Function

5)      F, it is a geometric property

6)      Noise

7)      Penumbra p=(FSSxOID)/SOD

8)      Communication

9)      Fast Exposure Time

10)   A) Increases

B) Decreases

C) Decreases

1) Decreases

2) Decreases

3) Increases

AP Knee

February 28th, 2010 by RadiologyTech No comments »

Ap Knee

IR size: 10×12 inches

Shielding: Lead shield around waist

Patient Position: Instruct patient to lay supine. Ensure no rotation of the pelvis and fully extend legs

Part Position: Rotate leg internally 3 degrees or until the intererpicondylar line is parallel to the IR.

Central Ray: Center .5 inches below the apex of the patella. Depending on patient habitus you may need to angle the tube.
If ASIS to tabletop measures:
<19 cm angle 3-5 degrees caudad
19-24 cm no angle
>24 cm angle 3-5 degrees cephalic

SID: 40 inches

Collimation: Collimate to lateral skin margins

Respiration: patient does not hold respiration.

Lateral Lower Leg

February 28th, 2010 by RadiologyTech No comments »

Lateral Lower Leg

IR size: 14×17 inches

Shielding: Lead shield around waist

Patient Position: Instruct patient to lay supine. With leg fully extended in an AP position.

Part Position: Ensure foot and ankle are in AP positions

Central Ray: Center at midpoint of leg ensure you have both the ankle and knee joints on there. You may need to put the IR diAgonally to fit parts in a single film

SID: 40-48 inches

Collimation: Collimate to lateral skin margins, include both joints

Respiration: patient does not hold respiration.

AP Lower Leg

February 27th, 2010 by RadiologyTech No comments »

AP Lower Leg

IR size: 14×17 inches

Shielding: Lead shield around waist

Patient Position: Instruct patient to lay supine. With leg fully extended in an AP position.

Part Position: Ensure foot and ankle are in AP positions

Central Ray: Center at midpoint of leg ensure you have both the ankle and knee joints on there. You may need to put the IR diAgonally to fit parts in a single film

SID: 40-48 inches

Collimation: Collimate to lateral skin margins, include both joints

Respiration: patient does not hold respiration.

Lateral Ankle (mediolateral)

February 27th, 2010 by RadiologyTech No comments »

Lateral Ankle

IR size: 10×12 inches

Shielding: Lead shield around waist

Patient Position: Flex affected limb 45 degrees, then place opposite leg behind the injured leg.

Part Position: carefully dorsiflex the foot if possible

Central Ray: Direct central ray to medial malleolus

SID: 40 inches

Collimation: Collimate to outer margins of the foot

Respiration: patient does not hold respiration.

AP Mortise Ankle

February 27th, 2010 by RadiologyTech No comments »

Ap Mortise Ankle

IR size: 10×12 inches

Shielding: Lead shield around waist

Patient Position: Instruct patient to lay supine. Patient can dorsiflex foot is no pain is being felt.

Part Position: Rotate entire leg and foot 15-20 degrees until the intermalleolar line is parallel to the IR.

Central Ray: Center in between malleoli

SID: 40 inches

Collimation: Collimate to lateral skin margins, include half of metatarsals and the distal tibia and fibula.

Respiration: patient does not hold respiration.

AP Ankle

February 27th, 2010 by RadiologyTech No comments »

Ap Ankle

IR size: 10×12 inches

Shielding: Lead shield around waist

Patient Position: Instruct patient to lay supine. Patient can dorsiflex foot is no pain is being felt.

Part Position: ensure the patients foot and ankle are in true AP and the lower leg is not rotated.

Central Ray: Center in between malleoli

SID: 40 inches

Collimation: Collimate to lateral skin margins, include half of metatarsals and the distal tibia and fibula.

Respiration: patient does not hold respiration.

Lateral Foot

February 27th, 2010 by RadiologyTech No comments »

Lateral Foot

IR size: 10×12 inches

Shielding: Lead shield around waist

Patient Position: Flex affected limb 45 degrees, then place opposite leg behind the injured leg.

Part Position: carefully dorsiflex the foot if possible

Central Ray: Direct central to medial cuneiform

SID: 40 inches

Collimation: Collimate to outer margins of the foot

Respiration: patient does not hold respiration.