The therapeutic ratio can be modified by:

The therapeutic ratio refers to the balance between the effectiveness of a treatment on tumor cells compared to its adverse effects on normal cells. Modifying this ratio to enhance treatment efficacy while minimizing side effects is crucial in oncology.

By radiosensitizing tumors, the treatment makes tumor cells more susceptible to radiation, which can lead to improved tumor control or eradication. This means that a lower radiation dose could achieve the same level of tumor killing, thereby reducing the potential damage to surrounding normal tissues. In this way, the therapeutic index is effectively increased as the desired therapeutic effect (tumor control) is enhanced while the risk of normal tissue damage is potentially lowered.

On the other hand, radioprotecting normal tissue involves strategies that help shield normal cells from the harmful effects of radiation. This protection further contributes to an increased therapeutic ratio by allowing for higher doses of radiation to be delivered to the tumor while sparing healthy tissues.

The other options do not directly contribute to improving the therapeutic ratio in the same context. For instance, increasing cellular repair mechanisms could potentially enhance the ability of normal tissues to recover from damage, but it may not directly modify the therapeutic ratio in terms of increasing tumor sensitivity or protecting normal tissue during concurrent treatments. Similarly, reducing chemotherapy doses does not generally