Thyroid Ultrasound

PDT can affect cancer tissue by three mechanisms: cancer cell necrosis, apoptosis, and destruction of blood vessels supplying cancer tissue; combination gives most durable effect.

“PDT can affect cancer tissue by three mechanisms, the combination of which gives the most durable, long-term effect. Cancer cell necrosis is a mechanism of unprogrammed cell death, occurring under the influence of large amounts of light.”

In PDT, photosensitizer absorbing light triggers chemical reactions generating reactive oxygen species and transitions PS to excited singlet state; type II reaction via singlet oxygen is the main mechanism of action.

“Absorbing light, it triggers numerous chemical reactions that result in the generation of reactive oxygen species and the transition of PS from the ground state to an unstable electronically excited singlet state.”

Wavelengths longer than 850 nm do not provide enough energy to produce sufficient reactive oxygen species and induce the desired therapeutic effect.

“On the other hand, wavelengths longer than 850 nm do not provide the amount of energy required to produce the appropriate amount of reactive oxygen species, and consequently - to induce the desired therapeutic effect. [28]”

Local PDT probably has an immunosuppressive effect, while systemic PDT is immunostimulant.

“Local PDT probably has an immunosuppressive effect, while systemic PDT is immunostimulant. [28]”

Wavelengths shorter than 600 nm penetrate tissue less and focus on superficial skin layers, contributing to light hypersensitivity.

“Shorter wavelengths - below 600 nm - penetrate the tissue less, focusing on the more superficial layers of the skin, which contributes to its hypersensitivity to light.”

PDT has low therapy costs compared to other oncological treatment methods.

“low therapy costs compared to other methods in oncological treatment”

PDT generates an immune response through earlier induction of inflammation; macrophages phagocytizing destroyed cancer cells indirectly stimulate Tc lymphocytes.

“A relatively recently discovered effect of PDT on cancer tissue is the generation of an immune response through the earlier induction of inflammation. Induction of necrosis and the effect on blood vessels causes a sudden release of inflammatory mediators, which then affect the host's immune system. Macrophages phagocytizing destroyed cancer cells indirectly stimulate Tc lymphocytes, which provide”

PDT can be combined with other treatment methods.

“Photodynamic therapy is undoubtedly a technique of the future, the main advantages of which are low invasiveness, the possibility of combining with other treatment methods, or the possibility of outpatient use.”

PDT can be used in outpatient settings.

“The main advantages of PDT include low therapy costs compared to other methods in oncological treatment, short therapy time, no long-term side effects, low invasiveness, possibility of use in outpatient settings, high effectiveness in killing cancer cells, also affecting the vascularization of the tumor, possibility of repeated use, no interaction with other treatment methods, leaving small scars”

PDT has no long-term side effects.

“no long-term side effects”

The wavelength used in PDT ranges from 600 nm to 1200 nm (optical window), with optimal therapeutic window 600-850 nm.

“The wavelength used ranges from 600 nm to 1200 nm, which is the optical window of the tissue, while the optimal range, called the therapeutic window, is 600 nm to 850 nm.”

PDT has low invasiveness.

“The main advantages of PDT include low therapy costs compared to other methods in oncological treatment, short therapy time, no long-term side effects, low invasiveness, possibility of use in outpatient settings, high effectiveness in killing cancer cells, also affecting the vascularization of the tumor, possibility of repeated use, no interaction with other treatment methods, leaving small scars”

PDT has high effectiveness in killing cancer cells and affects tumor vascularization.

“high effectiveness in killing cancer cells, also affecting the vascularization of the tumor”

The cytotoxic effect of PDT is caused by three components: light of a specific wavelength, photosensitizer, and molecular oxygen.

“The cytotoxic effect is caused by 3 components: light of a specific wavelength, photosensitizer (PS) and molecular oxygen.[28,30,31]”

Tissue hypoxia causes reduced ROS production and decreased PDT effectiveness, particularly in deeper solid tumors.

“Hypoxia of the tissue undergoing therapy causes reduced production of ROS and a decrease in the effectiveness of the treatment, which is particularly noticeable in solid tumors located deeper.”

Other disadvantages of PDT include possible skin hypersensitivity to light, lack of application in disseminated metastases, lack of application in poorly oxygenated tumors, and dependence on precision of irradiation.

“Other disadvantages of PDT reported in the literature include possible skin hypersensitivity to light after the procedure, lack of application in the case of disseminated metastases due to the selectivity of action and in poorly oxygenated tumors, dependence on the precision of irradiation of pathological tissue. [28]”