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Dosimetry Final > Dosimetry Midterm Questions for Final > Flashcards

Dosimetry Midterm Questions for Final Flashcards

1
Q

The majority of cancers in the head and neck are

A

d. Squamous Cell Carcinomas

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2
Q

A bite block is sometimes inserted between the patients teeth because

A

b. It helps the patient keep his/her mouth open during treatment so more of the oral mucosa can be excluded from the radiation field

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3
Q

In the treatment of head and neck cancer, immobilization is particularly important because

A

c. The proximity of several radiosensitive organs and often small tumor margins

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4
Q

To place a very large patient so that the head is in a neutral position

A

c. A high support is needed under the head

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5
Q

To treat the maxillary Antrum tumor without including the eye

A

b. the chin is extended and the chin is tilted back

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6
Q

Prior to starting treatment to boost fields, it is a good idea to take portal images because

A

a. skin and seed markers may have shifted and margins are small

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7
Q

Retinoblastoma is a tumor of the eye that usually occurs in

A

c. small children

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8
Q

The most common of all intracranial malignancies is

A

d. metastatic disease

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9
Q

The most commonly occurring cancer in the United States is

A

b. Lung Cancer

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10
Q

It is important to reproduce the patient’s position

A

c. As it was during the simulation procedure

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11
Q

Treatment fields in the chest should be designed

A

c. with respiratory motion in mind

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12
Q

The number of US women who develop breast cancer is

A

a. 1/8

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13
Q

Cardiac toxicity from breast irradiation is

A

a. sometimes a serious problem

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14
Q

The most important considerations to avoid radiation induced pneumonitis is

A

b. Total dose, fractionation schedule, and volume of irradiated lung

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15
Q

The abdomen is defined as

A

c. The portion of the body that lies between the thorax and pelvis and that contains the peritoneal cavity

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16
Q

The cephalic field margin in whole abdominal irradiation should be set

A

b. At the superior aspect of the diaphragm in quiet breathing

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17
Q

Generally speaking, the kidney tolerance to irradiation in the adult is

A

2000 cGy at 180 - 200 per fraction

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18
Q

The most common site of pancreatic tumors is

A

c. The head of the pancreas

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19
Q

The organs in which normal tissue tolerance is of concern when treating pancreatic tumors are

A

a. The kidneys, the liver, and the spinal cord

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20
Q

When pelvis irradiation is delivered to an obese patient, the advantage of a prone position is that

A

b. skin marks are more reliable to set up fields

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21
Q

When pelvis irradiation is delivered to an obese patient in the supine position, the concern is that

A

c. uncertainty of dose due to variations in patient thickness would be caused when attempts were made to eliminate skin folds

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22
Q

Methods to reduce the volume of small bowel in the pelvis include

A

a. surgically implanted expander, placement of a mesh sling and a prone position

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23
Q

Patients with carcinoma of the cervix are treated with a combination of external beam and intracavitary irradiation. However

A

b. In patients w more advanced disease, a larger proportion of the dose is delivered using external beam irradiation

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24
Q

Treating the pelvis and paraaortic lymph nodes in separate fields

A

c. It is not preferred because of concerns regarding field matching

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25
Q

When a patient is treated for a rectal carcinoma, it is treated in the prone position as opposed to the supine postition

A

b. The skin reaction between the buttocks is reduced

26
Q

Of gynecological tumors treated with radiation therapy, the most common type is

A

c. Squamous cell carcinoma of the cervix

27
Q

When a large patient is treated for a pelvic tumor using a four field box technique

A

b. secondary scatter off the collimator and block trays may be a problem

28
Q

A central pelvis is sometimes used in the treatment of opposed anterior and posterior fields following intracavitary irradiation

A

a. to protect the bladder, rectum, and tissues irradiated to a high dose via the intracavitary irradiation

29
Q

To reduce the volume of small bowel within the pelvic field

A

c. the patient’s position should be prone on a belly board

30
Q

7.1 The term gross tumor volume, as defined by ICRU, means

A

c. The gross palpable or visible/demonstrable tumor extent and location of malignant growth

31
Q

7.2 The term clinical target volume, as defined by ICRU, means

A

a. A tissue volume that contains a demonstrable GTV and/or subclinical microscopic malignant disease, which has to be eliminated

32
Q

7.4 When parallel opposed fields are used and the isocenter is at mid depth in the chest, the length of the spinal cord is

A

d. Longer in the anterior field than in the posterior

33
Q

7.6 When parallel opposed fields are used and the isocenter is at mid depth in the chest

A

the anterior port film should appear

34
Q

7.6 When parallel opposed fields are used and the isocenter is at mid depth in the chest

A

a. the anterior port film should appear exactly the same as the anterior simulation w respect to anatomy

35
Q

7.7 A circular magnification device, which is 5 cm in diameter, is placed on the patient’s anterior surface where the SSD is 100 cm. The simulation film is at 135 cm from the target (TFD). The magnification of the device is

A

a. 1.35

135/100

36
Q

7.13 A treatment-planning CT scan is different from a diagnostic CT scan because

A

b. In a treatment planning CT scan, the patient is never given contrast

37
Q

7.14 A contour of a patient taken for calculating an isodose distribution

A

a. must be accurate because it has an effect on the dose

38
Q

7.17 Discrepancies in the patient/beam alignment between the first port film and the simulation film may be due to

A

b. Differences in laser alignment systems, different couch tops, differences in clothing under the patient,

39
Q

7.18 Uncertainties associated w delivering radiation therapy can be totally avoided by

A

d. No special means, since there is no method by which all uncertainties can be avoided

40
Q

7.19 When the treatment fields are designed by the radiation oncologist, margins are always added around a tumor because of

A

a. Uncertainties in determining the tumor extent, penumbra of the beam, and patient motion

41
Q

8.1 When a linear accelerator w one independently moving leaf is used w a wedge in the beam, there is a chance that the independent jaw cannot be used because

A

d. The collimator may have to be turned in a direction such that the independent jaw cannot be used

42
Q

8.2 The attenuation of cerrobend is

A

b. about 15 percent less than lead

43
Q

8.4 To reduce the risks of ingestion of small fragments of the alloy in a block cutting room, the following precautions should be taken:

A

b. Practice good hygiene and wash hands before eating, drinking, and smoking

44
Q

8.5 Multileaf collimators are different from custom-shaped blocks because

A

a. They produce steplike field edges, leakage can occur between leaves, and they can only be used with limited field sizes

45
Q

8.6 Custom-made electron shields are different from custom-made blocks for photon beams because

A

d. They have no focused edges and are much thinner; also, the size of the opening is practically the same as the field on the skin surface

46
Q

8.9 When a lip lesion is treated, it is possible to reduce the mucosal reaction by

A

b. Placing an internal shield distal to the tumor and covering the shield with wax

47
Q

8.12 Bolus material is used to

A

c. reduce the depth of the maximum dose when photon beams are being used

48
Q

8.14 Departmental weekly chart rounds should include verifying

A

b. Presence of diagnosis and histology, and stage; presence of consent for treatment; presence of pathology report; presence of dose prescription dated and signed; and weekly port films of each field approved, signed, and dated by the radiation oncologist

49
Q

8.15 The frequency of port films varies, but they

A

c. should always be taken on the first day of treatment

50
Q

8.17 Various methods of documenting the treatment parameters include

A

b. Tattoo, photograph of ea treatment field, and a port film of ea field

51
Q

8.18 If a 30 degree wedge is left out of the treatment during two of five treatments,

A

d. the central axis dose is increased and the isodose distribution is affected

52
Q

8.19 When an error in dose delivery is discovered

A

a. The attending radiation oncologist should be notified

53
Q

8.20 Treatment field should be labeled in the chart with reference to

A

b. an anatomic description, and it should have a unique number

54
Q

16.1 Afterloading techniques were developed primarily to reduce

A

c. Exposure to personnel

55
Q

16.2 Radioactive sources frequently used in tandem and ovoids are in the shape of

A

a. tubes

56
Q

16.3 Radioactive isotopes used in tandems and ovoids are usually

A

c. cesium 137

57
Q

16.4 Point A is defined in gynecological implants to be a point located

A

d. 2 cm cephalad of the cervical os and 2 cm lateral to the uterine tandem

58
Q

Ophthalmic plaques can be constructed for use with

A

all of the above (cobalt 60, iodine 125, ruthenium 106, iridium 192)

59
Q

isotopes used in permanent implants are most frequently

A

iodine 125 and gold 198

60
Q

surface molds can be used to treat all of the following tumors except

A

a deep-seated tumors in the pelvis side wall

61
Q

in handling radioactive sources, long-handled instruments must be used to?

A

reduce the exposure to the hands of the loader

Dosimetry Final (2 decks)

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