Bremsstrahlung refers to:

 # Bremsstrahlung refers to: 

a. the primary source of X-rays from an X-ray tube 

b. Characteristic radiation emitted when an electron is displaced from the outer shell of a tungsten atom in the target 

c. the electromagnetic spectrum 

d. particulate radiation 

The correct answer is: A. a. the primary source of X-rays from an X-ray tube. 

BREMSSTRAHLUNG RADIATION: The sudden stopping or slowing of high-speed electrons by tungsten nuclei in the target produces bremsstrahlung photons, the primary source of radiation from an x-ray tube. (Bremsstrahlung means “braking radiation” in German.)

Multiple punched out radiolucencies is a feature of:

 # Multiple punched-out radiolucencies is a feature of: 

a. Multiple Myeloma 

b. Thalassemia 

c. Fibrous Dysplasia 

d. Ewing's Sarcoma 

The correct answer is A. Multiple myeloma.

The periphery of multiple myeloma lesions is well-defined but not corticated; it lacks any sign of bone reaction. The lesions have been described as appearing “punched out.” However, many appear ragged and even infiltrative. Some lesions have an oval or cystic shape. Untreated or aggressive areas of destruction may become confluent, giving the appearance of multilocularity.

Bleeding time is prolonged in:

 # Bleeding time is prolonged in:

A. Hemophilia

B. Von willebrand disease

C. Telangiectasia

D. Henoch Schonlein purpura 

The correct answer is B. Von Willebrand disease.

Von Willebrand disease (VWD) is the most common hereditary blood-clotting disorder in humans. An acquired form can sometimes result from other medical conditions. It arises from a deficiency in the quality or quantity of von Willebrand factor (VWF), a multimeric protein that is required for platelet adhesion. It is known to affect several breeds of dogs as well as humans. The three forms of VWD are hereditary, acquired, and pseudo or platelet type. The three types of hereditary VWD are VWD type 1, VWD type 2, and VWD type 3. Type 2 contains various subtypes. Platelet type VWD is also an inherited condition.

The various types of VWD present with varying degrees of bleeding tendency, usually in the form of easy bruising, nosebleeds, and bleeding gums. Women may experience heavy menstrual periods and blood loss during childbirth.

Severe internal bleeding and bleeding into joints are uncommon in all but the most severe type, VWD type 3.

Hair-on-end appearance in a skull roentgenogram is seen in:

 # " Hair-on-end" appearance in a skull roentgenogram is seen in:

a. Fibrous dysplasia 

b. Thalassemia 

c. Garre's Osteomyelitis 

d. Paget's Disease 

The correct answer is B. Thalassemia.

Similar to sickle cell anemia, the features of thalassemia generally result from hyperplasia of the ineffective bone marrow and its subsequent failure to produce normal red blood cells. However, these changes are usually more severe than with other anemias. There is a generalized radiolucency of the long bones with cortical thinning. In the skull, the diploic space exhibits marked thickening, especially in the frontal region. The skull also shows a generalized granular appearance, and occasionally a “hair-on-end” effect may develop.