Radiosurgery for non-malignant diseases

Radiosurgery for non-malignant diseases

By: Dr. Alejandro Blanco Saborio

Radiosurgery or SRS For its acronym in English, it is a concept devised by Neurosurgeon and Professor Lars Leksell in 1952, however, the first treatment could not be performed until the 60's, when the idea of using radiation to produce a change in a tissue, this idea was quickly transferred to tumors located in the central nervous system (CNS).

In our time, the use of this “energy” instrument has revolutionized the management of non-malignant tumors, Like the Meningiomas, Schwannomas, Pituitary adenomas, where it has demonstrated tumor control rates superior to 90% at 10 or more years of follow-up.

Another field of much research, functional disorders,  like pain, the most frequent representative of them is Trigeminal Neuralgia, where in patients refractory to drugs or do not qualify or desire microvascular decompression surgery (when we talk about classic Neuralgia) Radiosurgery could provide relief to users. There is a lot of research currently on the different “targets” that could be useful for relief, we hope that we will soon have more studies on this.

Finally, in the area of neuro-vascular,  Radiosurgery is considered the best therapy for arteriovenous malformations or cavernous angiomas, non-surgical due to eloquent or deep location.

Today, advances in engineering, computing and artificial intelligence contribute enormously to this technique continuing to gain more and more space in modern life in Neuro-Oncology, Neurovascular and functional disorders in the CNS.

 

Equipment
First world.

At the Siglo XXI Radiotherapy Medical Center we have cutting-edge technology for the application of cranial and body radiosurgery. The implementation of artificial intelligence tools such as our Elements planning software in conjunction with our Brainlab ExacTrac equipment – real-time monitoring – allows us to provide the best possible treatment scheme.

This, added to the human resource with the most experience in the country in radiosurgery issues: highly trained personnel, in constant training and in constant review of protocols for the application of the best treatments.

Understanding the importance of adequate time between each radiotherapy session

Understanding the importance of adequate time between each radiotherapy session (rests and exposure to the radiation beam)

By: Dr Rolando Loría

Radiotherapy It is a treatment commonly used in the management of various types of cancer. Radiation is given in fractions (sessions) to maximize damage to cancer cells while minimizing the impact on surrounding normal tissues. The rate of cell death is a crucial aspect in the effectiveness of radiotherapy treatment.

When we talk about the medical term “intra-fraction elongated intervals,” we are referring to the time separation between radiation doses within a treatment. Administration of fractionated doses allows normal cells time to repair damage caused by radiation, while cancer cells, which often have a more limited repair capacity, can accumulate damage and eventually die (Shibamoto, Miyakawa, Otsuka , & Iwata, 2016).

If the times between doses are too short, normal cells may not have enough time to recover, which may increase the risk of side effects. On the other hand, if the intervals are too long, cancer cells may have time to repair some of the damage, reducing the effectiveness of the treatment.

The average times between each radiotherapy session They will depend on the dose and the treatment scheme, however the minimum “rest” time between one session and another is approximately 6 hours in Brain injuries and 8 hours in body injuries.

Maximum “rest” times They will vary between 24 or 48 hours between each session depending on the indicated treatment scheme.

EXHIBITHION TIME

In addition to this, there is another important variable to consider: the times of exposure to radiation during treatments.

The expert Khorramizadeh and collaborators demonstrated that when the exposure time to the radiation beam per session increases from 15 minutes to 45 minutes in each fraction (treatment session), the death of tumor cells is reduced. It seems that the main phenomenon that affects the cellular response is the repair of sublethal damage. The effect of the dose administered over 15 minutes may be greater than that of 30 and 45 minutes (Khorramizadeh, Saberi, & Tahmasebi-Bi, 2017).

High dose equipment such as the Linear Accelerator that the XXI Century Radiotherapy Medical Center, They allow radiosurgery doses to be delivered extremely accurately in the maximum periods indicated in these studies, achieving not only the expected cellular damage but also contributing to the patient's comfort by not being exposed to long periods of treatment as happens in other radiosurgery equipment.

The rate of cell death in radiotherapy depends on several factors, including the sensitivity of the cells to radiation damage, the type of radiation used, the total dose administered, and the dose fraction. The relationship between cell death rate and specific intra-fraction intervals may vary depending on the type of cancer and treatment (Benedict, Lin, Zwicker, Huang, & Schmidt-Ullrich, 1997).

It is important to note that radiotherapy treatment planning is carried out in a personalized manner for each patient, taking into account various clinical and radiobiological factors. Radiation oncologists work to optimize the delivery of radiation to achieve maximum effectiveness against cancer while minimizing side effects on normal tissues.

Bibliography

Khorramizadeh, M., Saberi, A., & Tahmasebi-Bi, M. (September 1, 2017). Impact of Prolonged Fraction Delivery Time Modeling Stereotactic Body Radiation Therapy with High Dose Hypofractionation on the Killing of Cultured ACHN Renal Cell Carcinoma Cell Line. J Biomed Phys Eng(3), 205-216.

Shibamoto, Y., Miyakawa, A., Otsuka, S., & Iwata, H. (2016). Radiobiology of hypofractionated stereotactic radiotherapy: what are the optimal fractionation schedules? J Radiat Res.(57 Suppl 1), 76-i82.

Benedict, S., Lin, P., Zwicker, R., Huang, D., & Schmidt-Ullrich, R. (Mar 1, 1997). The effectiveness of intermittent biological irradiation as a function of overall treatment time: development of correction factors for linac-based stereotactic radiotherapy. Int J Radiat Oncol Biol Phys., 37(4), 765-9.