<prompt> A patient with cancer developed extreme degree of radiation toxicity. Further history revealed that the dose adjustment of a particular drug was missed during the course of radiotherapy. Which of the following drugs required a dose adjustment during radiotherapy in order to prevent radiation toxicity?VincristineDactinomycinCyclophosphamide6- Mercaptopurine  <response>: Ans. B DactinomycinRef: Katzung 10th894Anthracyclines and actinomycin-D dactinomycin can cause severe radiation toxicity. This is known as radiation recall syndrome. 