Devita, Hellman, and Rosenberg's Cancer

LWBK1006-07 LWW-Govindan-Review November 22, 2011 13:54

86 DeVita, Hellman, and Rosenberg’s CANCER: Principles and Practice of Oncology Review

Question 7.4. Which of the following statements describes the dose-related cellular

response to radiation?

A. In mammalian cells, there is generally a linear relationship between

the cell killing and the dose given.

B. The term “D 0 ” describes the slope of the exponential survival curve

and represents a dose required to reduce the surviving fraction to

37%.

C. Both mammalian cells and bacterial cells display “shoulder” in the

low-dose region.

D. In general, postirradiation conditions that accelerate the cell division

are the ones most favorable to repair of potentially lethal damage.

Question 7.5. Which of the following statements is FALSE regarding independent events

(4 R’s) that occur during fractionated radiotherapy?

A. Repopulation refers to spontaneous repopulation and induced cell

proliferation or recruitment of cells after irradiation.

B. Repair explains the shoulder of the radiation survival curve showing

that cells can repair some of the radiation damage.

C. Redistribution explains migration of cells away from an irradiation

source.

D. Reoxygenation explains how the proportion of hypoxic cells present

in a tumor returns to preradiation level.

Question 7.6. Which of the following acute effects is NOT related to radiation-induced

cell death?

A. Cystitis

B. Esophagitis

C. Fatigue

D. Proctitis

E. None of the above

Question 7.7. Nonirradiated cells can express all of the following responses after radi-

ation damage to neighboring cells, EXCEPT:

A. Gene induction

B. Induction of genomic instability

C. Differentiation

D. Changes in apoptotic potential

E. Double-stranded breaks in DNA

Question 7.8. Which of the following best describes the modern linear accelerator?

A. A modern linear accelerator (LINAC) can deliver energies up to

1 MeV.

B. The^60 Cobalt teletherapy unit is a megavoltage machine that relies

on radioactive cobalt to produce an electron beam.

C. Unlike LINAC, the^60 Cobalt unit is always “on” and must be kept in

a shielded position until the beam is needed for treatment.

D. The focal point of the gantry’s rotation is called the field edge.