What factors does radiosensitivity depend on?

What factors does radiosensitivity depend on?

Radiosensitivity depends on several factors. These factors include the ability to repair damage, hypoxia, cell cycle position, and growth fraction. In addition, the volume of the initial tumor has been demonstrated to influence the ability to eradicate tumors.

What are radiosensitive cells?

Radiosensitivity is the relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation. The most radio-sensitive cells are those which: have a high division rate. have a high metabolic rate. are of a non-specialized type.

Is oxygen a radiosensitizer?

Oxygen is a potent radiosensitizer, increasing the effectiveness of a given dose of radiation by forming DNA-damaging free radicals. Tumor cells in a hypoxic environment may be as much as 2 to 3 times more resistant to radiation damage than those in a normal oxygen environment.

What is individual radiosensitivity?

Individual radiation sensitivity. The term “radiation sensitivity” describes the sensitivity of organisms to the effect of ionising radiation.

What is radiosensitivity and radioresistance?

In this regard, there are two opposite terms: radiosensitivity and radioresistance, the former referring to the susceptibility and the latter to the strength of the tumour towards radiation.

Is doxorubicin a radiosensitizer?

Colony-forming assays demonstrated that composite doxorubicin-loaded micelles are radiosensitive, as shown by significantly reduced survival of cells treated by radiation + composite micelles compared with those treated with radiation + free doxorubicin or radiation alone.

Is chemotherapy a radiosensitizer?

Radiosensitizers can be drugs that kill or inhibit growth of cancer cells, like chemotherapy, or drugs that only kill cancer cells when combined with radiation, says David Kozono, MD, PhD, radiation oncologist at Dana-Farber/Brigham and Women’s Cancer Center.

Is cisplatin a radiosensitizer?

The fact that a terminal cisplatin lesion results in inhibition of DNA-PKcs catalyzed kinase and autophosphorylation activity59 60, indicates that both NHEJ and HR catalyzed repair of DNA DSBs containing cisplatin lesions would be inhibited and therefore contribute to the radiosensitization activity of cisplatin.

What cells which divide rapidly are radiosensitive cells?

basal cells , which divide rapidly, are radiosensitive cells. some cells are more radiosensitive than others , identify the most radiosensitive tissues and organs. using Insight film instead of d-type film reduces the time that the patient is exposed to radiation by up to 50%.

What makes a tissue system more radiosensitive?

Stem cells are radiosensitive. The more mature the cell the more sensitive. The older the tissue or organ, the more radiation resistant it is. The lower the metabolic activity, the higher the resistance.

What are the factors that affect tissue radiosensitivity?

Tissue radiosensitivity. 2. Radiation Pathology Of Tissues  The response of a tissue or organ to radiation depends primarily on three factors: 1. the inherent sensitivity of the individual cells 2. the kinetics of the population as a whole of which the cells are a part 3.

Are the general laws of radiosensitivity relevant to radiotherapy?

THE general laws governing radiosensitivity were recognized many years ago and have always been an important guide in radiotherapy. The early investigators soon observed wide differences in the reactions of various tumors and adjusted their methods accordingly.

What is the difference between radioresistance and radioresponsiveness?

Radiosensitivity refers to the inherent response of cancer cells to radiation, and radioresponsiveness refers to how quickly a tumor regresses after radiation. Navneet Sharda, David Boothman, in Encyclopedia of Cancer (Second Edition), 2002 Radioresistance varies in different phases of the cell cycle.

What is radio-resistance and why does it matter?

Radio-resistance represents a major issue in the success of radiation therapy in oncology. Radiation therapy causes cell death by inducing stress and DNA damage, but some cells may survive, by activating DNA repair, unfolded protein response (UPR), or autophagy, thereby leading to tumor regrowth and recurrence ( Kim et al., 2019 ).