Image-guided radiation therapy (IGRT) is the use of imaging during radiation therapy to improve the precision and accuracy of treatment delivery. IGRT is used to treat tumors in areas of the body that move, such as the lungs.
Full Answer
What is the current use of imaging in Radiation Oncology?
Apr 10, 2014 · The primary goal of treatment planning is to precisely calculate the radiation dose to the tumor in order to improve the outcome and reduce toxicity. The future of imaging in radiation therapy treatment planning is promising, and other advances will contribute to better target definition.
What are the goals of radiation therapy treatment planning?
Feb 25, 1997 · The principal uses of images in radiation therapy planning are to precisely define the target of the radiation treatment (PTV), to define the radiation beam portals for each direction of radiation, and to evaluate a treatment plan under consideration. All of these tasks are performed with a computer simulation system known as a radiation treatment planning …
How has Medical Imaging changed the use of ionizing radiation?
Imaging in treatment planning Fluoroscopy and computed tomography. Early radiotherapy planning was based on body surface landmarks alone. Conventional or fluoroscopic simulation acquires 2-dimensional (2D) images for radiotherapy planning based on internal anatomic landmarks and limited tissue-density information.
Does CT imaging have a role in radiation therapy?
Image-guided radiation therapy (IGRT) is the use of imaging during radiation therapy to improve the precision and accuracy of treatment delivery. IGRT is used to treat tumors in areas of the body that move, such as the lungs. Radiation therapy machines are equipped with imaging technology to allow your doctor to image the tumor before and during treatment.
Why is there a need of imaging in radiotherapy?
What is imaging in radiotherapy?
What is the primary purpose of radiation therapy?
Why is imaging important in cancer?
When is image guided radiation therapy used?
How effective is stereotactic radiation therapy?
What is the indication when radiation is on?
What is the primary difference of the teletherapy and the brachytherapy?
What is the purpose of chemotherapy treatment?
What is imaging in healthcare?
What is MRI scan for?
What is tumor imaging?
What is radiation therapy?
There are two, general classes of radiation therapy: brachytherapy and teletherapy. “Brachy,” a Greek word, means short distance and “tele” means long distance. Brachytherapy is treatment performed by placing the radioactive source near or in contact with a tumor, that is, the use of intracavitary or intraluminal placement of the treatment source.
What is the use of ionizing radiation for cancer?
The use of ionizing radiation for cancer treatment has undergone extraordinary development during the past hundred years. The advancement of medical imaging has been critical in helping to achieve this change. The invention of computed tomography (CT) was pivotal in the development of treatment planning.
What is fusion imaging?
In medical applications, these points are the same anatomical regions of the body, such as bone and organs, for the same patient. Fusion is the ability to display different types of registered images anatomically overlain on one another in a single, composite image [ 33#N#A. Ardeshir Goshtasby and S. Nikolov, “Image fusion: advances in the state of the art,” Information Fusion, vol. 8, no. 2, pp. 114–118, 2007. View at: Publisher Site | Google Scholar#N#See in References#N#]. Fusion provides the best information for each image, that is, geometric definition and tissue density from the CT image, soft-tissue contrast from the MR image, and metabolic information from the PET image. The combined information reduces the uncertainty regarding the tumor definition for geometric localization as well as determining the size and spread of the disease. By improving the accuracy of the target definition, image fusion can potentially improve the treatment outcome and decrease complications as less normal tissue is irradiated.
How does image fusion improve radiation treatment?
By improving the accuracy of the target definition, image fusion can potentially improve the treatment outcome and decrease complications as less normal tissue is irradiated. Currently, most radiation treatment planning systems support image registration and fusion. There are several fusion algorithms.
What type of accelerator is used for radiation therapy?
Another type of accelerator used in radiation therapy is a betatron which has a hollow, doughnut shape with an alternating magnetic field to accelerate electrons. These accelerators were used specifically for the production of therapeutic electron beams, rather than X-rays. Most of these units were installed in European medical centers, had electron energies up to 50 MeV, and were used to treat deeply located tumors.
What are the three main aspects of cancer treatment?
The three most important aspects of cancer treatment are surgery, chemotherapy (in earlier times referred to simply as medicine), and radiation therapy . Of these, surgery is the oldest with records discovered by Edwin Smith, an American Egyptologist, and describing the surgical treatment of cancer in Egypt circa 1600 B.C. [ 1#N#R. E. Pollock and D. L. Morton, “Principles of surgical oncology,” in Cancer Medicine, D. W. Kufe and R. E. Pollock, Eds., B. C. Decker, Hamilton, Ontario, Canada, 2000. View at: Google Scholar#N#See in References#N#]. Medicines were also used in ancient Egypt at the time of the pharaohs, although the use of chemotherapy in cancer was first used in the early 1900s by the German chemist, Paul Ehrlich [ 2#N#V. T. de Vita Jr. and E. Chu, “A history of cancer chemotherapy,” Cancer Research, vol. 68, no. 21, pp. 8643–8653, 2008. View at: Publisher Site | Google Scholar#N#See in References#N#]. In contrast, radiation therapy, the therapeutic use of ionizing radiation, is by far the most recent technique used to treat cancer. X-rays, a kind of ionizing radiation, were discovered in 1895 by Wilhelm Roentgen and within months were used to treat tumors. This use of ionizing radiation has undergone extraordinary development during the past century. As we will discuss, the advancements in medical imaging have been critical to the evolution of modern radiation therapy.
Why is treatment planning important?
The primary goal of treatment planning is to precisely calculate the radiation dose to the tumor in order to improve the outcome and reduce toxicity. The future of imaging in radiation therapy treatment planning is promising, and other advances will contribute to better target definition.
Why is image guidance important in radiotherapy?
The goal of image guidance during radiotherapy is to ensure proper targeting and delivery of radiation. Radiation planning, margins, and patient immobilization setups are very important and work alongside image-guided radiation therapy (IGRT) to assist with proper delivery. 53 Table 1 summarizes differences between IGRT techniques.
What is the future of imaging in radiotherapy?
60 With the advent of theragnostics, advanced imaging techniques, such as FLT-PET, DCE CT/MRI, and CuATSM imaging, may allow us to tailor our radiotherapy based on the response to initial chemotherapy and radiation treatment, further enhancing our ability to improve the therapeutic ratio .
What is a sonographer?
Sonography is a common IGRT modality requiring a probe in the appropriate position to aid setup before treatment commences. These images can be combined with CT-based imaging to help visualize the target. Real-time sonography with the transducer held in place by a robot during treatment is under development. In general, sonography provides the lowest resolution of IGRT and does have a learning curve, but is easy to set up, reduces the patientʼs exposure to ionizing radiation seen with other IGRT modalities, and clinically, it has been used in breast and prostate radiotherapy treatments. 58 Infrared (IR) tracking uses external reflective markers either directly on the patient, or on a stereotactic frame, as a proxy to track target motion. Similarly, optical tracking matches surface anatomy and so is limited to treatment regions close to the surface, such as in the breast. Radiofrequency targeting, such as Calypso (Varian Medical Systems, Palo Alto, CA), offers a method for real-time tracking and is FDA approved for use in prostate cancer patients 59 and was recently approved for use with skin-based fiducial markers.
What is CT simulation in radiotherapy?
Conventional or fluoroscopic simulation acquires 2-dimensional (2D) images for radiotherapy planning based on internal anatomic landmarks and limited tissue-density information. Computed axial tomography (CT) became available in the 1970s, but the developments in computer processing speed, memory, and applications specifically for use in radiotherapy did not allow CT simulation to become feasible until the late 1990s. 1 To compare traditional to modern techniques, a study was conducted of 30 patients whose cancer treatments were planned with surface markings, fluoroscopy, and CT simulation. 2 The authors showed that CT simulation increased the dose to the target and reduced the dose to surrounding normal structures more significantly than the older technologies using surface markers and fluoroscopy. The current standard in most countries is CT-simulator-based treatment planning for optimal coverage of target volumes and sparing of normal structures, although fluoroscopy simulation is still widely used in developing countries.
What is the most commonly used radiotracer in combination with PET?
18 F-FDG is the most commonly used radiotracer in combination with PET. 18 F-FDG is a glucose analogue taken up by cells via glucose transporters. After entering the cell, 18 F-FDG is phosphoryated by an enzyme called hexokinase, resulting in the molecule being trapped within cells. FDG accumulates in tissues with high cellular activity requiring increased glucose uptake and consumption. Particularly upregulated in tumor cells is the inefficient glycolytic pathway that is preferentially used for ATP generation. 11 18 F-FDG uptake is not specific for tumor cells; it also localizes within inflamed and infected tissues that are also metabolically active and depend heavily on the glycolysis pathway.
What is peripheral kV imaging?
Peripheral kV imaging improves the contrast of anatomy over MV due to the larger range of attenuation of kV photons in tissue. However kV systems require accurate calibration to the treatment isocenter. For 3D imaging, cone-beam CT (CBCT) is reconstructed using a ‘cone’ of photons rotating around the patient, imaging an entire 10- to 30-cm section at once, while in conventional CT, the 3D image is formed by translating the patient and imaging only a few slices at a time with a ‘fan’ beam (FBCT). Due to the large width of the cone beam used to image the patient, considerable photon scatter degrades the CBCT image compared to the conventional CT image. The CBCT technologies can have energies in the kV or MV range with the caveat that kV technology is a peripheral imaging device. Tomotherapy (Accuray Inc, Sunnyvale, CA) uses a narrow fan beam for imaging, but with MV photons. For the best image quality, CT on rails places a diagnostic CT scanner in the treatment vault. 55-57 The difference between mega- and kilo-volt and cone- and fan-beam is illustrated in Figure 3. It should be noted that choice of IGRT depends on the target and surrounding structures. For example, the most efficient IGRT for a tumor adjacent to the vertebral column would be a plain film, however, an intra-abdominal tumor surrounded by soft tissue would benefit the most from CT-based imaging.
What is DCE imaging?
Dynamic contrast-enhanced (DCE) CT and MRI imaging allows visualization of vasculature within tumors and surrounding tissues. Vascular properties that can be examined include blood flow, blood volume, and permeability. 30 Blood vessels formed in angiogenesis are imperfect, displaying tortuosity and high permeability. In malignant gliomas, cerebral blood volume (CBV) and permeability assessed by DCE are consistently linked to worse outcomes. Several studies have related high-tumor CBV or a fraction of the tumor volume that has a high CBV with a shorter time to progression and worse overall survival (Figure 2). 31,32 CBV has been used during a course of RT to assess early treatment response. 33 With this information, additional radiation dose can be targeted to those to areas, which appear to have more neovascularization, indicating high tumor activity and aggressiveness. Despite neovascularization, areas of the tumor may still be inadequately perfused and hypoxic due to the poorly functioning nature of these vessels. Hypoxic tumors are more resistant to radiotherapy. 11 Several studies investigated DCE-MRI to identify poorly enhancing tumors, indicating areas of hypoxia that may be resistant to radiotherapy. A study in cervical cancer showed local control and overall survival were better in those with minimal areas of poor enhancement versus those patients with large areas of enhancement. 34 Similar studies have been done in SCC of the head and neck, relating poor tumor perfusion as assessed by DCE-CT/MRI with increased local recurrence. 35, 36 The barrier to widespread use of DCE imaging is the lack of standardized imaging protocols that specify parameters for image acquisition, quantification of the results, and quality control for reproducibility and accuracy of the acquired images. 30 Several efforts are under way to address these technical issues and despite these hurdles, DCE imaging is currently being evaluated in over 40 clinical studies in the United States.
What is IGRT imaging?
In IGRT, imaging equipment is mounted on or built into the machine that delivers radiation, such as a linear accelerator. Imaging equipment may also be mounted in the treatment room. Imaging technologies used in IGRT include x-rays, computed tomography (CT), 3-D body surface mapping, magnetic resonance imaging (MRI) and ultrasound (US). Sometimes, IGRT is performed by a detector in the room which tracks motion by localizing markers on the surface of a patient, or electromagnetic transponders placed within the patient.
Who determines what area to treat and what dose to deliver?
The physician determines what area to treat and what dose to deliver. Together with the therapeutic medical physicist and the dosimetrist, the radiation oncologist determines what techniques to use to deliver the prescribed dose. The physicist and the dosimetrist then make detailed treatment calculations.
What is IGRT in medical terms?
Image-guided radiation therapy (IGRT) is the use of imaging during radiation therapy to improve the precision and accuracy of treatment delivery. IGRT is used to treat tumors in areas of the body that move, such as the lungs. Radiation therapy machines are equipped with imaging technology to allow your doctor to image the tumor before ...
Why does radiation therapy smell?
Patients may sometimes smell an odd smell during treatment that is caused by the ozone produced by the linear accelerator.
How long does it take for radiation side effects to go away?
Radiation therapy can cause early and late side effects. Early side effects occur during or immediately after treatment and are typically gone within a few weeks. Common early side effects of radiation therapy include tiredness or fatigue and skin problems.
What are the side effects of radiation?
Common early side effects of radiation therapy include tiredness or fatigue and skin problems. Skin in the treatment area may become more sensitive, red, irritated, or swollen. Other skin changes include dryness, itching, peeling and blistering. Depending on the area being treated, other early side effects may include: ...
What is the procedure for IGRT?
If you are to undergo IGRT, your doctor will likely use CT scanning to conduct a treatment simulation session and to create reference images. Other imaging procedures, such as MRI or PET scan, may be used to help determine the exact shape and location of your tumor, and a special device may be created to help you maintain the same exact position during each treatment. Your doctor will give you specific instructions based on the type of exam being performed.
What is radiation therapy?
Radiation therapy uses high-energy beams of radiation to control cancer and noncancerous tumors. By adding detailed images, IGRT ensures the powerful radiation is narrowly focused at the treatment area.
Why is IGRT used in radiation treatment?
IGRT is used as part of radiation treatment plans because it offers: Accurate delivery of radiation. Improved definition, localization and monitoring of tumor position, size and shape before and during treatment. The possibility of higher, targeted radiation dosage to improve tumor control.
What is IGRT before radiation?
When undergoing IGRT, high-quality images are taken before each radiation therapy treatment session. IGRT may make it possible to use higher doses of radiation, which increases the probability of tumor control and typically results in shorter treatment schedules.
What is IGRT used for?
IGRT is used to treat all types of cancer, but it's particularly ideal for tumors and cancers located very close to sensitive structures and organs. IGRT is also useful for tumors that are likely to move during treatment or between treatments. IGRT is used as part of radiation treatment plans because it offers:
What is IGRT treatment?
IGRT may involve a variety of 2-D, 3-D and 4-D imaging techniques to position your body and aim the radi ation so that your treatment is carefully focused on the tumor in order to minimize harm to healthy cells and organs nearby.
What is the use of ionizing radiation for cancer?
The use of ionizing radiation for cancer treatment has undergone extraordinary development during the past hundred years. The advancement of medical imaging has been critical in helping to achieve this change. The invention of computed tomography (CT) was pivotal in the development of treatment planning. Despite some disadvantages, CT remains the only three-dimensional imaging modality used for dose calculation. Newer image modalities, such as magnetic resonance (MR) imaging and positron emission tomography (PET), are also used secondarily in the treatment-planning process. MR, with its better tissue contrast and resolution than those of CT, improves tumor definition compared with CT planning alone. PET also provides metabolic information to supplement the CT and MR anatomical information. With emerging molecular imaging techniques, the ability to visualize and characterize tumors with regard to their metabolic profile, active pathways, and genetic markers, both across different tumors and within individual, heterogeneous tumors, will inform clinicians regarding the treatment options most likely to benefit a patient and to detect at the earliest time possible if and where a chosen therapy is working. In the post-human-genome era, multimodality scanners such as PET/CT and PET/MR will provide optimal tumor targeting information.
How can nanomaterials be used in cancer treatment?
Suitably engineered nanomaterials can enhance cancer radiotherapy by increasing the tumor selectivity and decreasing side effects. Additionally, the nanomaterial platform offers therapeutically valuable functionalities, including molecular targeting, drug/gene delivery, and adaptive responses to trigger drug release. The potential of such nanomaterials to be combined with radiotherapy is widely recognized. In order for further breakthroughs to be made, and to facilitate clinical translation, the applicable principles and fundamentals should be articulated. This review focuses on mechanisms underpinning rational nanomaterial design to enhance radiation therapy, the understanding of which will enable novel ways to optimize its therapeutic efficacy. A roadmap for designing nanomaterials with optimized anticancer performance is also shown and the potential clinical significance and future translation are discussed.
What is radiation therapy?
Imaging and radiation therapies are painless procedures that provide you with a more focused treatment. These procedures are designed to specifically place radiation in, or near, the tumor all while minimizing damage to surrounding healthy tissue. SSM Health radiation oncologists are leaders in their field of radiation therapy.
What is IGRT radiation?
Image-Guided Radi ation Therapy, or IGRT, uses 2D and 3D imaging to determine the exact location of cancerous tumors before or during radiation therapy treatments . This on-board imaging tracks the tumor’s position as it may shift slightly. Radiation beams are adjusted to pinpoint the cancerous area, maximizing treatment to the cancerous cells and it is used to treat tumors that are likely to move such as lung cancers.
What is SBRT used for?
SBRT is often used for treatment of tumors or lesions that may not respond well to surgery, chemotherapy, standard radiation or other treatments. For tumors and lesions in difficult locations, SBRT allows the physician to safely deliver high doses of radiation to the tumor while limiting dose to critical surrounding structures.
What is SSM radiation oncology?
SSM Health radiation oncologists are leaders in their field of radiation therapy. They use some of the latest radiation treatment options in the fight against cancer.
What is SBRT treatment?
It’s a precise and accurate delivery system. Each SBRT treatment is called a "fraction" and is sometimes called "fractionated" therapy.
How does mammosite work?
MammoSite® is a patented process delivering radiation into a breast after a tumor has been removed through a lumpectomy. After the tumor is removed, a small balloon is attached to a thin catheter tube. This is then placed inside the lumpectomy cavity after a small incision is made in the breast. Next, the balloon is inflated with a saline solution so fitting snugly within the open cavity.
What is HDR in breast cancer?
During treatment a computer- controlled High Dose Rate (HDR) machine is connected to a portion of the catheter that remains outside the breast. Once your radiation oncologistdetermines the necessary amount of radiation, it is delivered by the machine through the catheter. No radiation remains in the breast between treatments.
Abstract
Introduction to Radiation Therapy
Past: Introduction of Imaging in Radiation Therapy Planning
Present: What Is Used in Practice Today
Future Considerations
- The primary goal of treatment planning is to precisely calculate the radiation dose to the tumor in order to improve the outcome and reduce toxicity. The future of imaging in radiation therapy treatment planning is promising, and other advances will contribute to better target definition. Higher resolution imaging will be developed for all of the m...
Conflict of Interests
Acknowledgments