which is stronger cobalt treatment or linear accelerator.

In brief, Cobalt is an older form of radiation. LINAC

(Linear Accelerator) is the newer and best form of radiation. Cancer incidence is increasing alarmingly over the years.

Full Answer

What is the difference between cobalt therapy and linear accelerator?

What is the Difference Between Cobalt Therapy and Linear Accelerator? In brief, Cobalt is an older form of radiation. LINAC (Linear Accelerator) is the newer and best form of radiation. Cancer incidence is increasing alarmingly over the years.

Why linac beam is better than cobalt-60 gamma ray beam?

The characteristics of the Linac beam and output are superior to Cobalt-60 gamma ray beam. At the present time the treatment machine to population ratio ranges from 12 machines per million in US to fewer than 0.3 machines per million in china.

What is the difference between cobalt-60 and low energy linac?

While the high energy Linacs (with x-ray and variably energy electron generating potential) are expensive, Low energy Linacs (4-6 MV) compare favourably with traditional cobalt units in terms of cost as well as uptime. The characteristics of the Linac beam and output are superior to Cobalt-60 gamma ray beam.

What are the benefits of a linear accelerator?

On the treatment center side, modern linear accelerators are compact with built-in beam’s eye view and a maneuverable couch that provides ease and reproducibility of treatment setups. This also minimize daily radiation exposure to staff. Very good beam matching can be delivered in case the patient needed to be transferred to a second LINAC machine.

What is the difference between cobalt and a linear accelerator?

The simplicity of cobalt units gives them the advantage of reduced maintenance, running costs and downtime when compared with linear accelerators. However, treatments carried out on such units are typically limited to simple techniques.

What is the difference between cobalt-60 and Linac?

Build-up: for cobalt-60 beams, the depth of the dose maximum is 5 mm, whereas for a 6 MV linac it is 16 mm. A greater depth of dose maximum is important for skin sparing and deep-seated tumours. photon beams is smaller than that for the cobalt-60 gamma ray beam used without trimmers.

What are the disadvantages of linac against cobalt-60?

Staffing levels can be higher for linacs and more staff training is required for linacs. Life cycle costs are higher for linacs, especially multi-energy linacs. Security is more complex for cobalt-60 machines because of the high activity radioactive source.

What is the difference of linear accelerator to cobalt-60?

While the high energy Linacs (with x-ray and variably energy electron generating potential) are expensive, Low energy Linacs (4-6 MV) compare favourably with traditional cobalt units in terms of cost as well as uptime. The characteristics of the Linac beam and out put are superior to Cobalt-60 gamma ray beam.

Is cobalt treatment still used?

Cobalt treatment still has a useful role to play in certain applications and is still in widespread use worldwide, since the machinery is relatively reliable and simple to maintain compared to the modern linear accelerator.

How does a linear accelerator work in radiotherapy?

The linear accelerator uses microwave technology (similar to that used for radar) to accelerate electrons in a part of the accelerator called the “wave guide”. Then, it allows these electrons to collide with a heavy metal target to produce high-energy x-rays.

What are the advantages of cobalt?

The main benefits of cobalt alloys are the wear resistance and the strength of the material. It also has the ability to work under extreme temperatures. Because of its durability though, it is an expensive alloy. Due to its cost, it is imperative that it is forged as perfectly as possible.

What are the side effects of cobalt radiation?

Because it decays by gamma radiation, external exposure to large sources of Co-60 can cause skin burns, acute radiation sickness, or death. Most Co-60 that is ingested is excreted in the feces; however, a small amount is absorbed by the liver, kidneys, and bones.

What are the pros of cobalt-60?

The advantages of Co/sup 60/ therapy over conventional x-ray therapy, stemming from the fact that in the lst instance energy absorption within the tissues is by the Compton effect and in the 2nd case by the photoelectric effect, are: (1) increased skin tolerance, (2) reduced bone absorption, (3) increase in depth dose, ...

How does radiotherapy work with cobalt-60?

Cobalt-60 systems, like the Gamma Knife, deliver radiation beams through 192 circular pinholes in a fixed helmet worn by the patient. The pinhole radiation meets at the tumor site, delivering a high dose, while the surrounding healthy tissue and critical brain structures receive minimal radiation.

What type of radiation is used in brachytherapy?

Brachytherapy is a form of radiation therapy where a sealed radioactive source is placed, inside, on or near the tumour. Brachy comes from the Greek word for short. It is often thought of as 'internal radiation therapy'. These sources produce gamma-rays, which have the same effect on cancer cells as X-rays.

What is the half life of cobalt-60?

5.26 yearsCobalt-60 decays continuously. The time taken to lose 50% of its initial activity, i.e., its half-life, is 5.26 years. Usually 10% of the cobalt-60 is replenished annually.

What is the advantage of cobalt beams?

The simplicity of cobalt units gives them the advantage of reduced maintenance, running costs and downtime when compared with linear accelerators. However, treatments carried out on such units are typically limited to simple techniques. This study has explored the use of cobalt beams for conformal and intensity-modulated radiotherapy (IMRT). Six patients, covering a range of treatment sites, were planned using both X-ray photons (6/10 MV) and cobalt-60 gamma rays (1.17 and 1.33 MeV). A range of conformal and IMRT techniques were considered, as appropriate. Conformal plans created using cobalt beams for small breast, meningioma and parotid cases were found to compare well with those created using X-ray photons. By using additional fields, acceptable conformal plans were also created for oesophagus and prostate cases. IMRT plans were found to be of comparable quality for meningioma, parotid and thyroid cases on the basis of dose-volume histogram analysis. We conclude that it is possible to plan high-quality radical radiotherapy treatments for cobalt units. A well-designed beam blocking/compensation system would be required to enable a practical and efficient alternative to multileaf collimator (MLC)-based linac treatments to be offered. If cobalt units were to have such features incorporated into them, they could offer considerable benefits to the radiotherapy community.

What is Cobalt 60?

BACKGROUND: Cobalt‑60 (Co‑60) teletherapy machines are still in use in most developing countries because of their minimal power requirements, reduced operational cost, and since the source does not vary in energy, the amount of quality assurance required to ensure “good beam” is dramatically reduced. Although as the machine wear, the chances of leakage radiation increase. AIMS AND OBJECTIVES: The aim of this study was to determine if leakage radiation at 5 cm and 1 m from the Co‑60 teletherapy source head is within the acceptable tolerance limit set by the International Electro‑technical Commission (IEC) and to determine if controlled and supervised areas within working hours were within the Institute of Physics and Engineering in Medicine (IPEM) limit. MATERIALS AND METHODS: The machine used was a Theratron® Phoenix Cobalt 60 Teletherapy machine. A RadEye™ B20‑ER Multi‑Purpose Survey Meter was used to measure mean time‑average dose rate (TADR) at various points in the controlled and supervised areas. Instantaneous dose rate (IDR) for leakage radiation was measured at 5 cm from the source head using the same Survey Meter and a measuring tape. In addition, measurement was made at 1 m from the normal treatment distance in patient and nonpatient planes. RESULTS: The mean TADR at beam OFF position in the controlled area at four different areas was 2.15 ± 0.48 μSv/h, which was <7.5 μSv/h IPEM limit and mean TADR in the supervised area at six different areas was 1.70 ± 0.45 μSv/h, which was also <2.5 μSv/h IPEM limit. The percentage IDR leakage radiation at beam OFF position at 5 cm and 1 m was within 200 μSv/h and 20 μSv/h IEC tolerance limit, respectively. Percentage leakage radiation at beam ON in patient plane was below the maximum and average IEC tolerance limit and nonpatient planes at 1 m was below 0.5% IEC limit. CONCLUSION: Supervised and controlled areas were within the acceptable range. Leakage radiation was within the tolerance limit.

What is compensator IMRT?

Purpose: We propose a novel compensator-based IMRT system designed to provide a simple, reliable, and cost-effective adjunct technology, with the goal of expanding global access to advanced radiotherapy techniques. The system would employ easily-reusable tungsten bead compensators that operate independent of a gantry (e.g. mounted in a ring around the patient). Thereby the system can be retrofitted to existing linac and cobalt teletherapy units. This study explores the quality of treatment plans from the proposed system and the dependence on associated design parameters. Methods: We considered 60 Co-based plans as the most challenging scenario for dosimetry and benchmarked them against clinical MLC-based plans delivered on a linac. Treatment planning was performed in the Pinnacle treatment planning system with commissioning based on Monte Carlo simulations of compensated beams. 60 Co-compensator IMRT plans were generated for five patients with head-and-neck cancer and five with gynecological cancer and compared to respective IMRT plans using a 6 MV linac beam with an MLC. The dependence of dosimetric endpoints on compensator resolution, thickness, position, and number of beams was assessed. Dosimetric accuracy was validated by Monte Carlo simulations of dose distribution in a water phantom from beams with the IMRT plan compensators. Results: The 60 Co-compensator plans had on average equivalent PTV coverage and somewhat inferior OAR sparing compared to the 6MV-MLC plans, but the differences in dosimetric endpoints were clinically acceptable. Calculated treatment times for head-and-neck plans were 7.6±2.0 min vs. 3.9 ± 0.8 min (6MV-MLC vs. 60 Co-compensator) and for gynecological plans were 8.7±3.1 min vs. 4.3 ± 0.4 min. Plan quality was insensitive to most design parameters over much of the ranges studied, with no degradation found when the compensator resolution was finer than 6 mm, maximum thickness at least 2 tenth-value-layers, and more than 5 beams were used. Source-to-compensator distances of 53 and 63 cm resulted in very similar plan quality. Monte Carlo simulations suggest no increase in surface dose for the geometries considered here. Simulated dosimetric validation tests had median gamma pass rates of 97.6% for criteria of 3% (global)/3mm with a 10% threshold. Conclusions: The novel ring-compensator IMRT system can produce plans of comparable quality to standard 6MV-MLC systems. Even when 60 Co beams are used the plan quality is acceptable and treatment times are substantially reduced. 60 Co-compensator IMRT plans are adequately modeled in an existing commercial treatment planning system. These results motivate further development of this low-cost adaptable technology with translation through clinical trials and deployment to expand the reach of IMRT in low- and middle-income countries. This article is protected by copyright. All rights reserved.

What is IMRT treatment?

This analysis evaluates the feasibility and dosimetric results of a simplified intensity-modulated radiotherapy (IMRT) treatment using a cobalt-therapy unit for post-operative breast cancer. Fourteen patients were included. Three plans per patient were produced by a cobalt-60 source: A standard plan with two wedged tangential beams, a standard tangential plan optimized without the use of wedges and a plan based on the forward-planned "field-in-field" IMRT technique (Co-FinF) where the dose on each of the two tangential beams was split into two different segments and the two segments weight was determined with an iterative process. For comparison purposes, a 6-MV photon standard wedged tangential treatment plan was generated. Dmean, D98%, D2%, V95%, V107%, homogeneity, and conformity indices were chosen as parameters for comparison. Co-FinF technique improved the planning target volume dose homogeneity compared to other cobalt-based techniques and reduced maximum doses (D2%) and high-dose volume (V110%). Moreover, it showed a better lung and heart dose sparing with respect to the standard approach. The higher dose homogeneity may encourage the adoption of accelerated-hypofractionated treatments also with the cobalt sources. This approach can promote the spread of breast conservative treatment in developing countries.

How to treat breast cancer in telecobalt unit?

Aim: To treat breast cancer patients in telecobalt unit with image based conformal radiotherapy planning using the multi-isocentric technique. Background: Breast cancer is the leading cancer among all the female cancers. With improved screening techniques, many patients are being diagnosed at an early stage and the need for radiotherapy in such patients has increased. The telecobalt machine is still a preferred machine in many of the low income countries as it is cost-effective and can offer uninterrupted treatment to large number of patients. Materials and methods: Three hundred patients requiring radiotherapy had a computed tomography based planning. Patients were immobilized using a breast board with a thermoplastic mould. Three dimensional planning was done with the multi-isocentric technique. These patients were then simulated using a Nucletron Simulix digital simulator for field verification and were treated in a Theratron Phoenix telecobalt treatment unit. Results: The doses to the heart, ipsilateral lung and the conformity index were within the recommended values. The homogeneity index was not comparable; however, a section by section qualitative analysis was done and a final plan approved. As per the RTOG toxicity grading system, acute skin reaction grade 3 was observed in 3.6% of treatments to intact breast including nodal regions and in 3.5% of post mastectomy radiation patients. Conclusion: Single isocenter technique was not feasible as the telecobalt unit did not have multileaf collimators and asymmetric jaws. With improved image based planning, a multi-isocentric technique was planned. By evaluating the dose distribution, beam modifications can be made and treatments can be given with acceptable toxicity.

How many Cobalt 60 units are there?

According to the Directory of Radiotherapy Centres (DIRAC) there are 2348 Cobalt-60 (Co-60) teletherapy units worldwide, most of them in low and middle income countries, compared to 11046 clinical accelerators. To improve teletherapy with Co-60, a mechanical Multi-Leaf Collimator (MLC) was developed, working with pneumatic pressure and thus independent of electricity supply. Instead of tungsten, brass was used as leaf material to make the mechanical MLC more affordable. The physical properties and clinical applicability of this mechanical MLC are presented here. The leakage strongly depends on the fieldsize of the therapy unit due to scatter effects. The maximum transmission through the leaves measured 2.5 cm from the end-to-end gap, within a field size of 20 cm × 30 cm defined by jaws of the therapy unit at 80 cm SAD, amounts 4.2%, normalized to an open 10 cm × 10 cm field, created by the mechanical MLC. Within a precollimated field size of 12.5 cm × 12.5 cm, the end-to-end leakage is 6.5% normalized to an open 10 cm × 10 cm field as well. This characteristic is clinically acceptable considering the criteria for non-IMRT MLCs of the International Electrotechnical Commission (IEC 60601-2-1). The penumbra for a 10 cm × 10 cm field was measured to be 9.14 mm in plane and 8.38 mm cross plane. The clinical applicability of the designed mechanical MLC was affirmed by measurements relating to all relevant clinical properties such as penumbra, leakage, output factors and field widths. Hence this novel device presents an apt way forward to make radiotherapy with conformal fields possible in low-infrastructure environments, using gantry based Co-60 therapy units.

What is Co-60 IMRT?

Purpose: This work describes a commercial treatment planning system, its technical features, and its capabilities for creating Co-60 intensity modulated radiation therapy (IMRT) treatment plans for a magnetic resonance image guidance radiation therapy (MR-IGRT) system. Methods and Materials: The ViewRay treatment planning system (Oakwood Village, OH) was used to create Co-60 IMRT treatment plans for 33 cancer patients with disease in the abdominal, pelvic, thorax, and head and neck regions using physician-specified patient-specific target coverage and organ at risk (OAR) objectives. Backup plans using a third-party linear accelerator (linac)-based planning system were also created. Plans were evaluated by attending physicians and approved for treatment. The Co-60 and linac plans were compared by evaluating conformity numbers (CN) with 100% and 95% of prescription reference doses and heterogeneity indices (HI) for planning target volumes (PTVs) and maximum, mean, and dose-volume histogram (DVH) values for OARs. Results: All Co-60 IMRT plans achieved PTV coverage and OAR sparing that were similar to linac plans. PTV conformity for Co-60 was within <1% and 3% of linac plans for 100% and 95% prescription reference isodoses, respectively, and heterogeneity was on average 4% greater. Comparisons of OAR mean dose showed generally better sparing with linac plans in the low-dose range <20 Gy, but comparable sparing for organs with mean doses >20 Gy. The mean doses for all Co-60 plan OARs were within clinical tolerances. Conclusions: A commercial Co-60 MR-IGRT device can produce highly conformal IMRT treatment plans similar in quality to linac IMRT for a variety of disease sites. Additional work is in progress to evaluate the clinical benefit of other novel features of this MR-IGRT system.

How does orthovoltage work?

Orthovoltage was often used before linear accelerators became available for the treatment of many different tumors. Orthovoltage radiation uses lower energy photons to treat tumors, which are located on the skin or very close to the skin. The lower energy of orthovoltage beams doesn’t work well for deep tumors compared to the higher energy beams available today with most linacs. However, orthovoltage treatment can be very effective for some skin tumors and other superficial lesions. Orthovoltage units are becoming rare, as many of the treatments that were done previously by orthovoltage units are now treated with electrons.

What is volumetric modulated arc therapy?

Volumetric modulated arc therapy (also known as RapidArc). Photon beams are the same type of beam used in X-ray machines, like those used to take chest X-rays. However, in radiation therapy, much higher energy photon beams are used.

Why is IMRT used in cancer?

For example, if a tumor is close to or wrapped around a normal organ, IMRT can shape the radiation to avoid as much of the healthy tissue as possible. This is why IMRT is often used in cancers of the head and neck where many critical areas, such as the spinal cord, must be avoided.

Why are beams arranged?

Beams are then arranged to avoid healthy tissue, while giving a dose of radiation to the tumor. Computer software is used to see the amount of radiation the tumor and normal tissues receive to make sure that all parts of the tumor are covered, while healthy organs receive as little radiation as possible.

How does IGRT work?

During treatment with IGRT, imaging scans are done over and over to guide treatment. The scans are read by computer software to find changes in a tumor’s size and location. This allows for changes in position of the patient and/or the planned radiation dose. The many images can increase the accuracy of the radiation treatment and decrease the amount of radiation to the nearby normal tissue.

Does radiation therapy take a long time?

Planning does not take a long time and patients can usually start treatment quickly, compared to other kinds of radiation therapy that need more in-depth (and time consuming) planning. This type of treatment is often used for urgent treatments.