Radiation Oncology & Interventional Radiology
Eradication via Energy
Radiation therapy (RT) is a localized therapy (not systemic) that uses various forms of energy to destroy and kill cancer cells. This is different from radiology which is the use various forms of energy to produce images of/inside of the body.
"Radiotherapy is a critical therapy for cancer patients that causes DNA damage directly via ionizing radiation (IR) or by indirectly generating oxidative damage via reactive oxygen species (ROS), thereby leading to cancer cell destruction." (source)
Who does what within the radiology specialty?
- Radiologists: Read, interpret, and makes diagnoses based on imaging studies (these are the specialists who will perform and read all of your scans in partnership with radiation techs)
- Radiation Oncologists: Perform radiation treatments using high-powered targeted forms of energy to reduce or remove cancer from the body; these treatments may be curative or palliative in intent. Examples of treatments are SBRT (stereotactic body radiation therapy), brachytherapy, and proton radiation therapy.
- Interventional Radiologists: diagnose and treat conditions using minimally-invasive techniques, often as an alternative to surgery or more invasive procedures. Examples of procedures include RFA (radiofrequency ablation), chemoembolization, and port-a-cath placement.
- Radiology Technicians: Perform imaging studies like CT scans, MRIs, or PET scans.
- Radiation Therapists: perform radiation treatments on patients under the guidance of a radiation oncologist or interventional radiologist.
Relevant Terminology:
- Radiosensitive: a cancer that is vulnerable/susceptible to radiation therapy
- Radioresistant: a cancer that is resistant to or unaffected by radiation therapy
- Radiofrequency Ablation (RFA) or Rhizotomy: uses heat from radio waves to damage/destroy cancer cells
- Cryoablation/Cryosurgery: uses extremely cold temperatures directed at a tumor to kill cancer cells
- Microwave Ablation: uses electromagnetic waves focuses on the tumor to kill cancer cells
- Chemoembolization: combo therapy that block tumor blood supply and delivers chemo directly to tumor
- Radioembolization: combo therapy that blocks tumor blood supply and delivers radiation directly to the tumor (ytrium-90/y-90 beads or SIRT selective internal radiation therapy)
- Irreversible Electroporation: uses electromagnetic waves to attack cancer cells
- IGRT: image-guided radiotherapy
- SBRT: Stereotactic Body Radiotherapy (type of external beam radiation therapy)
- EBRT: External Beam Radiation Therapy (includes proton beam and photon beam procedures)
- Brachytherapy: implanted RT treatment
- Fractions: individual treatment sessions of radiotherapy
- Dose-Escalation: gradually increasing tolerable RT dose to destroy as much of the tumor as possible without sacrificing healthy surrounding tissue
- Medical Dosimetry: field of medicine specializing in dose calculations and measurements for radiotherapy with a focus on safety, accuracy, and efficacy
- Radiopharmaceuticals: drugs used as part of radiation therapy (Y-90, chemoembolization, etc.)
- Conversion Therapy: a treatment intended to make inoperable patients eligible for surgery
- Induction Therapy: a treatment or combination of treatments intended to eradicate all detectable cancer, induce remission in a patient
We have much more in store for this page so stay tuned. In the meantime, please take advantage of the resource collection at the bottom of this page and the histotripsy overview in the section below. You can also check out our Newly Diagnosed page for a thorough overview of the early cancer experience.
Interventional Radiology Treatment Modalities
Infographic Source: Society of Interventional Radiology
Emerging Radiation Therapy Technologies
Histotripsy
Microbubbles as Cancer Killers
Histotripsy, meaning "soft tissue breakdown," is a new, non-invasive alternative to cut, slash, burn treatments for liver tumors, approved by the FDA in October 2023. Histotripsy is a one-time local interventional ablation treatment that uses ultrasound waves to break up and liquefy tumor tissue in the liver by the creation and dissolution of microbubbles.
According to University of Michigan, who pioneered this technology, histotripsy won't make patients sick or cause damage to healthy tissues, and it's fast and painless. HistoSonics, in collaboration with U of M and backed by J&J, has created a robotic device called Edison® to apply this modality to patients' liver tumors.
This procedure is conducted by interventional radiologists and/or surgeons who are able to monitor the treatment effect in real time. Patients are put under general anesthesia and the device is lowered onto their abdomen to locate the tumor(s) in the liver and to deliver targeted sound waves to the desired area. As microbubbles form, expand, and collapse, they create strain and damage to the cancer cells, causing tumor tissue death.
As blood moves through the treated area following the procedure, the immune system picks up on antigens from the destroyed tumor cells, creates antibodies to combat those antigens, and can stimulate an immune response to further eradicate tumor cells.
Studies have also indicated a possible abscopal effect in which tumor cells elsewhere in the body (in an area not treated by histotripsy) are identified by the same antigens and are also attacked by the immune system.
To learn more about histotripsy, you can check out the resources at the bottom of this page, or you can visit here and here.
Alpha DaRT™ : Diffusing Alpha-Emitting Radiation Therapy
How Does Alpha DaRT Work?
Alpha DaRT THERAPY HIGHLIGHTS
- Minimally invasive cancer treatment for solid tumors
- Low toxicity, favorable safety profile
- Minimal damage to healthy tissues
- Potent, effective cancer-killing ability using radioactive alpha particles
- Set it and forget it: convenient, single application of therapy for patients in a quick, outpatient procedure
"While local radiation therapy has been a mainstay of cancer therapy for years, it has been mostly limited to modalities utilizing beta or gamma emissions. Alpha DaRT™ is the first localized anticancer therapy to utilize the specific therapeutic properties of alpha particles to treat solid tumors. Due to the inherent limited range of the alpha particles, the Alpha DaRT technology, directly inserted into a solid tumor, has the potential to kill cancerous cells with localized precision without damaging surrounding healthy tissues. This means that treatment with Alpha DaRT may produce fewer harsh side effects than standard cancer therapies such as chemotherapy, conventional radiation therapy, or invasive surgery. " (source)
RADIOACTIVE ALPHA PARTICLES
The Alpha DaRT™ technology , developed by Alpha Tau Medical, uses a metal scaffolding called a "seed" coated in Radium-224 to treat solid tumors. The metal seed is inert and biocompatible, and it is placed directly into the tumor. Once the seed is in position, Radium-224 will start to break down into daughter atoms, releasing harmful alpha particles through each transition, resulting in immediate and continuous treatment until removed.
"Alpha particles are known to be highly destructive to cancerous cells regardless of the cell’s lifecycle stage or level of oxygenation. Alpha particles directly damage the cell DNA, creating complex double-strand breaks that are lethal to the tumor. However, the short range of alpha particles in tissue (<0.1 mm) had, in the past, made them impractical for treating solid tumors." (source) However, "the alpha-emitting atoms [resulting from Alpha DaRT therapy] diffuse up to a few millimeters in the tumor, allowing the radiation to cover a zone with a diameter of up to 5mm." (source)
RADIUM-224 DECAY CHAIN
As Radium-224 (half-life of 3.7 days) decays into each of its successive daughter atoms, radioactive cancer-killing alpha particles are emitted. The first daughter atom created is Radon-220, with a half-life of less than a minute. Radon-220 exists as a gas so it is able to move through cancerous tissue with relative ease, releasing alpha particles as it moves along, eventually degrading into its next daughter molecule: Polonium-216. Polonium-216 decays into Lead-212 then Bismuth-212 then either Polonium-212 or Thallium-208 and finally Lead-208, with alpha particles released into the tumor tissue with each transition. Once the decay chain has reached its end, usually after a few days, the seeds are removed from the tumors. See the graphic below for a visual representation.
CLINICAL RESULTS
"Clinical results of the Alpha DaRT published in the International Journal for Radiation Oncology Biology, Physics, showed to be promising in terms of both safety and efficacy. The treatment was evaluated in 28 squamous cell carcinoma tumors of the skin and head & neck and achieved a >78% complete response rate despite the elderly (median age = 80.5 years) and heavily pretreated patient population. The treatment showed high safety with minimal local and no systemic toxicity." (source)
"The Alpha DaRT can potentially help patients who have radio-resistant or recurring tumors, who are ineligible for surgery, or for whom surgery would not have a meaningful impact on quality of life, or who otherwise would have limited treatment options. " (source)
Alpha DaRT™ Clinical Trials
"The Alpha DaRT cancer treatment is currently being investigated in clinical trials at leading cancer centers worldwide, such as Memorial Sloan Kettering New York (USA), University of Montreal (Canada), and National Cancer Center (Japan). Indications include skin cancer, oral cavity cancer and breast cancer. Further trials are in process for the investigation of additional cancer indications." (source)
Clinical trial participants are being actively recruited for trials focused in lung cancer, liver cancer, breast cancer, pancreatic cancer, prostate cancer, oral cavity cancer, and skin cancer.
- Learn more about Clinical Trials for Alpha DaRT here.
Radium-224 Decay Chain
This figure "shows how Radium-224 implanted into a tumor undergoes decay by emitting an energetic alpha particle and, through recoil energy, a daughter atom Radon-220 is released into the tumor tissue. Subsequently, other daughter atoms are released until the decay chain ends with a stable Pb-208 isotope in very small quantities that are not dangerous to the body." (source)
