Brachytherapy is a form of radiotherapy in which sealed radiation sources are placed inside or next to the area requiring treatment. Brachytherapy is commonly used as an effective treatment for cervical cancer, prostate, breast, and skin and can also be used to treat tumors in many other body sites. Treatment outcomes have shown that the rate of cure for brachytherapy cancer is proportional to surgery and external beam radiotherapy (EBRT) or enhanced when used in combination with this technique. Brachytherapy may be used alone or in combination with other therapies such as surgery, EBRT and chemotherapy.
Brachytherapy contrasts with unsealed source radiotherapy, in which therapeutic radiiuclides (radioisotopes) are injected into the body to chemically localize tissues that require destruction. This also contrasts with EBRT, where high-energy x-rays (or sometimes gamma rays from radioisotopes such as cobalt-60) are directed at tumors from outside the body. Brachytherapy involves even the proper placement of short-range radiation sources (radioisotopes) directly at the site of a cancerous tumor. It is enclosed in a protective capsule or wire, allowing ionizing radiation to escape to treat and kill surrounding tissue but prevent the radioisotope charge to move or dissolve in body fluids. This capsule may be removed later, or (with some radioisotopes) may be allowed to remain in place. A feature of brachytherapy is that irradiation affects only highly localized areas around the source of radiation. Exposure to radiation healthy tissue farther from the sources is therefore reduced. In addition, if the patient moves or if there is movement of the tumor in the body during treatment, the source of radiation maintains its correct position in relation to the tumor. Characteristics of brachytherapy provide an advantage over EBRT - tumors can be treated with very high local radiation doses while reducing the possibility of unnecessary damage to surrounding healthy tissue.
Travel brachytherapy can be completed in less time than other radiotherapy techniques. This can help reduce the chance of survival cancer cells to divide and grow in intervals between each dose of radiotherapy. Patients typically have fewer visits to radiotherapy clinics compared with EBRT, and may receive treatment as outpatients. This makes the treatment accessible and convenient for many patients. This brachytherapy feature means that most patients can tolerate the brachytherapy procedure very well.
The global market for brachytherapy reached US $ 680 million in 2013, where high dose rates (HDR) and LDR segments accounted for 70%. Microspheres and electronic brachytherapy consist of the remaining 30%. One analysis predicts that the brachytherapy market can reach more than US $ 2.4 billion by 2030, growing 8% per year, driven mainly by the microsphere market as well as electronic brachytherapy, which gained significant worldwide interest as user friendly technology. The word brachy is Greek for short distances.
Video Brachytherapy
Medical use
Brachytherapy is commonly used to treat cervical, prostate, breast, and skin cancers.
Brachytherapy may also be used in the treatment of brain tumors, eyes, head and neck area (lips, floor of mouth, tongue, nasopharynx and oropharynx), respiratory tract (trachea and bronchus), gastrointestinal tract (esophagus, gallbladder, bile- ducts, rectum, anus), urinary tract (bladder, urethra, penis), female reproductive tract (uterus, vagina, vulva), and soft tissue.
Because the source of radiation can be positioned appropriately in the tumor treatment site, brachytherapy allows high doses of radiation to be applied to small areas. Furthermore, because radiation sources are placed in or next to the target tumor, the sources retain their position in relation to the tumor when the patient moves or if there is a tumor movement inside the body. Therefore, the radiation source remains accurately targeted. This allows the doctor to achieve a high level of dose conformance - ensuring that all tumors receive optimal radiation levels. It also reduces the risk of damage to healthy tissue, organs or structures around the tumor, thereby increasing the chances of healing and preserving organ function.
The use of HDR brachytherapy allows reduced overall maintenance time compared to EBRT. Patients receiving brachytherapy should generally make fewer visits to radiotherapy compared with EBRT, and an overall radiotherapy treatment plan can be completed in a shorter time. Many brachytherapy procedures are performed on outpatients. This convenience may be particularly relevant for patients who must work, older patients, or patients living some distance from the care center, to ensure that they have access to radiotherapy treatments and adhere to treatment plans. Shorter treatment times and outpatient procedures can also help improve the efficiency of radiotherapy clinics.
Brachytherapy can be used with the aim of curing cancer in the case of a small or locally advanced tumor, provided the cancer has not metastasized (spread to other parts of the body). In properly selected cases, brachytherapy for primary tumors often represents a comparable surgical approach, achieving the same healing possibilities and with similar side effects. However, in advanced stage tumors, surgery may not routinely provide the best chance of recovery and is often technically feasible to do. In these cases radiotherapy, including brachytherapy, offers the only chance of recovery. At a later stage of the disease, brachytherapy can be used as a palliative treatment to relieve symptoms of pain and bleeding.
In cases where the tumor is not readily accessible or too large to ensure optimal distribution of irradiation to the treatment area, brachytherapy can be combined with other treatments, such as EBRT and/or surgery. Combination therapy of brachytherapy exclusively with chemotherapy is rare.
Cervical Cancer
Brachytherapy is commonly used in the treatment of early or localized cervical cancer and is a standard of care in many countries. Cervical cancer can be treated with brachytherapy LDR, PDR or HDR. Used in combination with EBRT, brachytherapy can provide better results than EBRT alone. Brachytherapy accuracy allows high doses of targeted radiation to be delivered to the cervix, while minimizing radiation exposure to nearby tissues and organs.
The possibility of remaining disease-free (survival-free) and remaining alive (overall survival) is similar to the treatment of LDR, PDR and HDR. However, the main advantage of HDR treatment is that any doses can be administered on an outpatient basis with short administration times providing greater comfort for many patients.
Prostate cancer
Brachytherapy for treating prostate cancer may be given either as a permanent LDR implantation or as a temporary HDR brachytherapy.
Permanent seed implantation is suitable for patients with localized tumors and a good prognosis and has been shown to be a very effective treatment to prevent cancer return. Survival rates are similar to those found with EBRT or surgery (radical prostatectomy), but with fewer side effects such as impotence and incontinence. This procedure can be completed quickly and patients can usually go home on the same day with treatment and return to normal activities after 1 to 2 days. Permanent seed implantation is often a less invasive treatment option compared with surgical removal of the prostate.
While HDD brachytherapy is a newer approach to treating prostate cancer, it is currently less common than seed implantation. It is primarily used to provide additional doses in addition to EBRT (known as "boost" therapy) as it offers an alternative method to provide high-dose radiation therapy that suits the tumor shape within the prostate, while saving radiation exposure to surrounding tissues. Brachytherapy HDR as a boost for prostate cancer also means that the EBRT course may be shorter than when EBRT is used alone.
Breast cancer
Radiation therapy is a standard of care for women who have undergone lumpectomy or mastectomy surgery, and is an integral component of breast conservation therapy. Brachytherapy may be used after surgery, prior to chemotherapy or palliation in case of advanced disease. Brachytherapy to treat breast cancer is usually done with brachytherapy while HDR. Postoperatively, breast brachytherapy can be used as a "boost" after radiation of the entire breast (WBI) using EBRT. Recently, brachytherapy itself is used to deliver APBI (partial shrinkage of breast shrinkage), which involves sending radiation only to the nearby region surrounding the original tumor.
The main benefit of breast brachytherapy compared to overall breast irradiation is that high doses of radiation can be appropriately applied to the tumor while saving radiation to healthy breast tissue and underlying structures such as ribs and lungs. APBI can usually be completed for one week. The choice of brachytherapy may be very important in ensuring that women who work, elderly or women without easy access to care centers can benefit from breast conservation therapy because of shorter treatment courses compared to WBI (which often require more visits for 1-2 months).
There are five methods that can be used to provide breast brachytherapy: Interstitial breast brachytherapy, intravenous breast brachytherapy, intraoperative radiation therapy, Permanent Breast Implantation and noninvasive breast brachytherapy using mammography for target localization and HDR sources.
Brachytherapy interstitial breast
Brachytherapy interstitial breast involves the temporary placement of some flexible plastic catheters in the breast tissue. It is carefully positioned to allow optimal radiation targeting into the treatment area while leaving the surrounding breast tissue. The catheter is connected to the afterloader, which gives the planned radiation dose to the treatment area. Brachytherapy interstitial breast can be used as a "boost" after EBRT, or as APBI.
Intraoperative radiation therapy
Intraoperative radiation therapy (IORT) provides radiation at the same time as surgery to remove the tumor (lumpectomy). The applicator is placed in the remaining cavity after removal of the tumor and the mobile electronic device generates radiation (either x-rays or electrons) and sends it through the applicator. Radiation is sent at once and the applicator is removed before closing the incision.
Brachytherapy intracaviter breast
Intrachavit brachytherapy (also known as "brachytherapy balloon") involves placing a single catheter into the left breast cavity after removal of the tumor (lumpectomy). Catheters may be placed at the time of lumpectomy or postoperatively. Through the catheter, the balloon is then inflated inside the cavity. The catheter is then connected to the afterloader, which gives the radiation dose through the catheter and into the balloon. Currently, intracaviter breast brachytherapy is only routinely used for APBI.
There are also devices that combine interstitial and intracavitary breast brachytherapy features (eg SAVI). This device uses many catheters but is inserted through a single entry point in the breast. Studies show the use of multiple catheters allows doctors to target more precise radiation.
Permanent breast implantation
Permanent breast-seed implantation (PBSI) infuses many radioactive "seeds" (small pellets) into the breast in the area around the tumor site, similar to a permanent prostate brachytherapy prostate. The seeds are implanted in one procedure 1-2 hours and give radiation for the next few months because the radioactive material in it decays. Risk of radiation from implant to person (eg spouse/couple) has been studied and found safe.
Skin cancer
Brachytherapy HDR for nonmelanomatous skin cancers, such as basal cell carcinoma and squamous cell carcinoma, provide alternative treatment options for surgery. This is particularly relevant for cancers of the nose, ears, eyelids or lips, where surgery can cause damage or require extensive reconstruction. Various applicators can be used to ensure close contact between the source of radiation (s) and skin, which corresponds to skin curvature and helps ensure precision delivery of the optimum irradiated dose.
Brachytherapy for skin cancer provides good cosmetic results and clinical efficacy; studies of up to 5 years of follow-up have shown that brachytherapy is very effective in terms of local control, and is proportional to EBRT. Treatment time is usually short, providing comfort for the patient. It has been suggested that brachytherapy can be a standard treatment for skin cancer in the near future.
Blood vessels
Brachytherapy can be used in the treatment of coronary stent-in-stent restenosis, in which a catheter is placed inside a blood vessel, where the sources are inserted and removed. In treating stent inenentententosis (ISR), stent Drug Eluting (DES) has been found to be superior to Intracoronary Brachytherapy (ICBT). However, there is a continued interest in vascular brachytherapy for persistent restenosis in failed stents and venous grafts. Therapy has also been studied for use in the treatment of peripheral vascular stenosis and is considered for the treatment of atrial fibrillation.
Maps Brachytherapy
Side effects
The possibility and potential nature of acute, sub-acute or long-term adverse events associated with brachytherapy depend on the location of the tumor being treated and the type of brachytherapy used.
Acute
Acute side effects associated with brachytherapy include local bruising, swelling, bleeding, discharge or discomfort in the implanted area. It usually goes away within a few days after the completion of treatment. Patients may also feel tired for short periods after treatment.
Brachytherapy treatment for cervical or prostate cancer can cause acute and temporary urinary symptoms such as urinary retention, urinary incontinence or painful urination (dysuria). Increased frequency of bowel movements, diarrhea, constipation or minor rectal bleeding, may also occur. Acute and subacute side effects usually heal in a matter of days or weeks. In the case of permanent brachytherapy (seeds) for prostate cancer, there is a small possibility that some seeds may migrate out of the treatment area into the bladder or urethra and passed in the urine.
Brachytherapy for skin cancer can cause shedding of the outer layer of skin (desquamation) around the treatment area in the weeks following therapy, which usually heals within 5-8 weeks. If the cancer is located on the lips, ulceration may occur as a result of brachytherapy, but usually disappears after 4-6 weeks.
Most of the acute side effects associated with brachytherapy can be treated with drugs or through dietary changes, and usually disappear over time (usually a matter of weeks), after treatment is complete. The acute side effects of HDR brachytherapy are broadly similar to EBRT.
Long-term
In a small number of people, brachytherapy can cause long-term side effects due to damage or disruption of adjacent tissues or organs. Long term side effects are usually mild or moderate in nature. For example, urinary and digestive problems may persist as a result of brachytherapy for cervical or prostate cancer, and may require ongoing management.
Brachytherapy for prostate cancer can cause erectile dysfunction in approximately 15-30% of patients. However, the risk of erectile dysfunction is related to age (older men are at greater risk than younger men) as well as the level of erectile function before receiving brachytherapy. In patients with erectile dysfunction, the majority of cases can be successfully treated with drugs such as Viagra. Importantly, the risk of erectile dysfunction after brachytherapy is less than after radical prostatectomy.
Brachytherapy for breast or skin cancer can cause scar tissue to form around the treatment area. In the case of breast brachytherapy, fat necrosis may occur as a result of fatty acids entering the breast tissue. This can cause breast tissue to become swollen and tender. Fat necrosis is a benign condition and usually occurs 4-12 months after treatment and affects approximately 2% of patients.
Safety around other
Patients often ask if they need to have special safety precautions around family and friends after receiving brachytherapy. If a temporary brachytherapy is used, there is no radioactive source left in the body after treatment. Therefore, there is no radiation risk on friends or family because it is close to them.
If permanent brachytherapy is used, the low-dose radioactive source (seed) remaining in the body after treatment - the radiation level is very low and decreases over time. In addition, irradiation affects only the tissues within a few millimeters of the radioactive source (ie the tumor being treated). As a precaution, some people who receive permanent brachytherapy may be advised not to hold a child or get too close to a pregnant woman for a short period after treatment. Radiation oncologists or nurses can give special instructions to patients and suggest how long they should be careful.
Type
Different types of brachytherapy can be defined according to (1) the placement of radiation sources in the target treatment area, (2) the level or 'intensity' of the irradiated dose delivered to the tumor, and (3) the duration of the delivery dose.
Source placement
The two main types of brachytherapy treatment in terms of placement of radioactive sources are interstitial and contact.
In the case of interstitial brachytherapy, the source is placed directly on the target tissue of the affected site, such as the prostate or breast.
Brachytherapy contact involves placing a radiation source in the space next to the target tissue. This space can be a body cavity (intracavitary brachytherapy) such as the cervix, uterus or vagina; body lumen (intraluminal brachytherapy) such as trachea or esophagus; or externally (brachytherapy surface) such as skin. Radiation sources may also be placed in the blood vessels (intravascular brachytherapy) for the treatment of coronary in-stent restenosis.
Dose rate
Brachytherapy dose rate refers to the level or 'intensity' with radiation delivered to the surrounding medium and expressed in Grays per hour (Gy/h).
Low-dose brachytherapy (LDR) involves implanting radiation sources that emit radiation at levels up to 2Ã, GyÃ, Â · h -1 . Brachytherapy LDR is commonly used for oral cavity cancer, oropharynx, sarcoma and prostate cancer
Brachytherapy rate-dose rate (MDR) is characterized by moderate rate of dose delivery, ranging from 2 GyÃ, Â · h -1 to 12Ã, GyÃ, Â · h -1 .
High dose brachytherapy (HDR) is when the dosing rate exceeds 12 GyÃ, Â · h -1 . The most common application of HDR brachytherapy is in cervical, esophageal, lung, breast and prostate tumors. Most HDR treatments are done on an outpatient basis, but this depends on the treatment site.
The brachytherapy dose (PDR) pulse rate involves short pulses of radiation, usually once an hour, to simulate the overall level and effectiveness of LDR care. Typical tumor sites treated by PDR brachytherapy are gynecological and head and neck cancers.
Duration of dosing
Placement of radiation sources in the target area may be temporary or permanent.
Brachytherapy temporarily involves placing the source of radiation for a certain period of time (usually a few minutes or hours) before it is withdrawn. The duration of specific treatment will depend on many different factors, including the required dose rates and the type, size and location of the cancer. In the LDR and PDR brachytherapy, the source usually remains in place up to 24 hours before removal, whereas in HDR brachytherapy this time is usually a few minutes.
Permanent brachytherapy, also known as seed implantation, involves placing small radioactive LDR seeds or pellets (the size of a grain of rice) in a tumor or a treatment site and leaving them there permanently to gradually decompose. For several weeks or months, the level of radiation emitted by the source will drop to almost zero. Inactive seeds then remain in the treatment site without lasting effects. Permanent brachytherapy is most commonly used in the treatment of prostate cancer.
Procedures
Initial planning
To accurately plan the brachytherapy procedure, a thorough clinical examination was performed to understand the characteristics of the tumor. In addition, various imaging modalities can be used to visualize the shape and size of the tumor and its relationship to surrounding tissues and organs. These include x-ray radiography, ultrasound, computed axial tomography (CT or CAT) scan and magnetic resonance imaging (MRI). Data from many of these sources can be used to create 3D visualization of tumors and surrounding tissues.
Using this information, an optimal radiation source distribution plan can be developed. This includes consideration of how the source operator (applicator), which is used to transmit radiation to the site of care, should be positioned and positioned. Non-radioactive applicators and usually plastic needles or catheters. The specific type of applicator used will depend on the type of cancer treated and the characteristics of the target tumor.
This initial planning helps to ensure that 'cold spots' (too little radiation) and 'hot spots' (too much irradiation) are avoided during the treatment, as these can each lead to treatment failure and side effects.
Insertion
Before a radioactive source can be sent to the tumor site, the applicator should be inserted and placed properly according to the initial plan.
Imaging techniques, such as x-rays, fluoroscopy and ultrasound are commonly used to help guide the applicator's placement to the correct position and to further refine the treatment plan. CAT scan and MRI can also be used. Once the applicator is inserted, they are placed in place against the skin using sutures or adhesive tape to prevent them from moving. Once the applicator is confirmed as being in the correct position, further imaging can be done to guide detailed maintenance planning.
Creation of virtual patients
Images of patients with in situ applicators were imported into treatment planning software and patients were taken to a special shielded room for treatment. The maintenance planning software allows multiple 2D images from the treatment site to be translated into 3D 'virtual patients', where applicator positions can be determined. The spatial connection between the applicator, the place of care and the surrounding healthy tissue in this 'virtual patient' is a copy of the relationship to the actual patient.
Optimize irradiation plan
To identify the optimal spatial and temporal distribution of the radiation source within the applicator of the embedded network or cavity, the maintenance planning software allows the virtual radiation source to be placed inside the virtual patient. The software shows a graphical representation of the irradiation distribution. This serves as a guide for the brachytherapy team to improve the distribution of resources and provide a treatment plan that is optimally adapted to the anatomy of each patient before the actual delivery of irradiation begins. This approach is sometimes called 'dose-painting'.
Treatment handling
The radiation source used for brachytherapy is always covered in non-radioactive capsules. Resources can be submitted manually, but more commonly delivered through a technique known as 'afterloading'.
Brachytherapy delivery is manually limited to some LDR applications, because of the risk of radiation exposure in clinical staff.
In contrast, afterloading involves accurate positioning of non-radioactive applicators at the site of care, which are then loaded with radiation sources. In manual afterloading, the source is sent to the applicator by the operator.
The remote afterloading system provides protection from radiation exposure to healthcare professionals by securing the source of radiation inside a sheltered safe. Once the applicator is properly positioned in the patient, they connect to an 'afterloader' machine (containing radioactive sources) through a series of connected guide tubes. The maintenance plan is sent to the afterloader, which then controls the source delivery along the guide tube to the predetermined position in the applicator. This process is only done after the staff is removed from the treatment room. Sources remain in place for a predetermined period of time, again following the treatment plan, following which they return along the tube into the afterloader.
After completing the transmission of radioactive sources, the applicator is carefully removed from the body. Patients usually recover quickly from brachytherapy procedures, allowing them to be frequently performed in outpatients.
Between 2003 and 2012 in US public hospitals, the hospital's fixed rate with brachytherapy (internal radiation therapy) had an average annual decline of 24.4 percent among adults aged 45-64 years and a 27.3 percent annual average decline average among adults aged 65-84 years. Brachytherapy is an OR procedure with the greatest change in hospital stay paid by Medicare and private insurance.
Radiation Source
Commonly used radiation source (radionuclides) for brachytherapy.
History
Brachytherapy dates from 1901 (shortly after the discovery of radioactivity by Henri Becquerel in 1896) when Pierre Curie suggested to Henri-Alexandre Danlos that radioactive sources could be incorporated into tumors. It was found that the radiation causes the tumor to shrink. Independently, Alexander Graham Bell also suggested the use of radiation in this way. At the beginning of the 20th century, techniques for the application of brachytherapy were pioneered at the Curie institute in Paris by Danlos and at St. Luke's and Memorial Hospital in New York by Robert Abbe.
Interstitial radium therapy was common in the 1930s. The golden beans filled with radon were used as early as 1942 until at least 1958. The golden skin was selected by Gino Failla around 1920 to protect the beta rays as it passed gamma rays. Cobalt needles were also used briefly after World War II. Radon and cobalt are replaced by radioactive tantalum and gold, before iridium rises to prominence. First used in 1958, iridium is the most commonly used artificial source for brachytherapy today.
Following early interest in brachytherapy in Europe and the US, its use declined in the mid-twentieth century due to radiation exposure problems on operators from manual applications from radioactive sources. However, the development of a remote afterloading system, allowing radiation to be shipped from a sheltered safe, and the use of new radioactive sources in the 1950s and 1960s, reduced the risk of unnecessary radiation exposure to operators and patients. This, along with recent advances in the three dimensional imaging modalities, computerized care planning systems and delivery equipment have made brachytherapy a safe and effective treatment for many types of cancer today.
The word "brachytherapy" comes from the Greek word ?????? brachys , which means "short distance" or "short".
Environmental hazards
Due to the small size of the source of brachytherapy and low control in the early decades, there is a risk that some of them have fled to the environment to become orphaned sources. The radium needle was found in the Prague playground in 2011, emitting 500 Ã,ÂμSv/h from a distance of one meter.
See also
- External beam radiotherapy
- Brachytherapy prostate
- Intra-operation radiotherapy target
- Unsampled source radiotherapy
- Nuclear medicine
- Intraoperative radiation therapy
- Contact X-ray brachytherapy (also called "electronic brachytherapy")
References
External links
- American Brachytherapy Society (ABS)
Source of the article : Wikipedia
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