Slackers radiation oncology fact stack
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Slackers Radiation Oncology Fact Stack PowerPoint PPT Presentation


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Slackers Radiation Oncology Fact Stack. Mike Ori. Disclaimer. These represent my understanding of the subject and have not been vetted or reviewed by faculty. Use at your own peril. I can’t type so below are common missing letters you may need to supply e r l

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Slackers Radiation Oncology Fact Stack

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Slackers Radiation Oncology Fact Stack

Mike Ori


Disclaimer

  • These represent my understanding of the subject and have not been vetted or reviewed by faculty. Use at your own peril.

  • I can’t type so below are common missing letters you may need to supply

  • e r l

  • I didn’t use greek letters because they are a pain to cut and paste in.


  • What are the five stages of cancer diagnosis and therapy


  • Screening

  • Diagnosis

  • Staging

  • Therapy

  • Follow-up


  • What is the most successful use of radiology for screening


  • Mammography


  • What is one area where radiology techniques have not been successful in screening


  • Ultrasound screening of the prostate


  • Explain the role of contrast kinetics in MRI


  • Wash-in and wash-out times help differentiate benign and malignant

  • Normal tissue tends to have slower wash-in and wash-out kinetics than tumor.


  • What is a sestamibi scan


  • Use of 99mTc-sestamibi to identify areas of angiogenesis and tumor.


  • Compare sestamibi scans to MRI


  • Uses ionizing radiation

  • Not as available as MR

  • Faster

  • Cheaper


  • What is octreotide scanning


  • A somatostatin-like compound that can interact wit somatostatin receptors on the surface of cells. Some types of cancer (neuro-endocrine mostly) are notable for such receptors.


  • Compare octreotide scanning to MRI/CT


  • Sometimes shows mets when other modalities don’t

  • Poorer anatomic localization than other modalities

  • Can be used to indicate treatment with yttrium 90-octrotide


  • What is MRI spectroscopy


  • The use of the MRI machine to perform spectroscopic analysis of tissue to look for marker compounds that indicate growth or abnormal metabolism.

  • Rarely used capability due to reimbursement


  • What radiographic techniques can be used to stage cancer


  • CT

    • The workhorse

  • PET

    • Especially when combine with CT

  • MRI

    • Increasing in use. Dominant in some areas

  • Radionucleotide bone scans

    • For skeletal mets

  • Ultrasound

    • Rarely


  • How does PET scanning work


  • Fluoro-D-Glucose is injected into the body. Hot spots appear in any tissue actively metabolizing glucose. This includes tumors but also inflammed and regnerating areas.


  • For what cancers is PET scanning approved


  • Non-small cell lung cancer

  • Colorectal cancer

  • Melanoma

  • Lymphoma

  • Head and neck cancer (not thyroid or CNS)

  • Esophageal

  • Cervical

  • Breast monitoring and restaging

  • Thyroid restaging


  • Explain radionucleotide bone scans


  • 99mTC-methylene diphosphonate is injected into the body and incorporated into hydroxyapatite in the bone by osteoblasts. Thus areas of bone growth are visible.

  • Needs follow-up anatomic imaging


  • What is the role of radioactive iodine in the treatment of thyroid neoplasia


  • RAI is used post surgery to destroy remaining thyroid tissue.


  • What is image guided therapy


  • The use of radiology techniques in the performance of treatment

  • Intra arterial chemo catheter

  • Embolization

    • Simple

    • Chemo

  • Alcohol ablation/cryotherapy

  • RF ablation

  • Focused ultrasound


  • What is RECIST


  • Response evaluation criteria in solid tumors is an heuristic used to quantify the change in a solid tumor over time.

    • CR = complete response

    • PR = partial response, 30% decrease

    • PD = progressive disease, 20% increase

    • SD = stable disease


  • What type of radiation is used in radiotherapy


  • Ionizing radiation such as x-rays, gamma rays, electrons, protons


  • What device produces the radiation used most predominantly in the US


  • The linear accelerator or linac


  • How many linacs can fit on the head of a pin?


  • None.


  • Differentiate teletherapy from brachytherapy


  • Teletherapy uses a radiation beam generated by source remote to the patient. This is your classic sci-fi death ray.

  • Brachytherapy places an intrinsically radioactive substance in close approximation to the target tissue.


  • What is linear energy transfer


  • The amount of energy transferred per unit length of track


  • What is the bragg peak


  • The point of maximum energy release along a track.


  • Differentiate directly ionizing from indirectly ionizing radiation


  • Directly ionizing radiation has sufficient energy to directly disrupt the atomic structure of DNA. Protons.

  • Indirectly ionizing radiation creates free radicals that damage DNA. X-rays.


  • What is the primary method of cell killing caused by radiation


  • Double stand DNA breaks that are improperly repaired.


  • Why are oxygenated cells more susceptible to radiation than are hypoxic cells


  • The ionizing process generates free electrons which are taken up by oxygen to generate oxygen radicals which attack DNA. In hypoxic conditions, less oxygen is available to generate free radicals.


  • Which phase of the cell cycle is sensitive to radiation? Which is resistant?


  • G1/M are sensitive

  • S is resistant


  • What factors influence the survival of a radiated cell?


  • Position in the mitotic cycle

  • Molecular checkpoint activation

  • Hypoxia

  • Repopulation


  • Describe how a 50Gy dose of radiation is delivered to patients


  • The dose is usually fractionated into multiple doses of ~2Gy. These are then delivered over the course of many days until the total prescription is delivered.


  • Describe image modulated radiation therapy


  • IMRT uses a multi-leaf collimator shape a radiation beam to limit exposure of adjacent structures.


  • List several benign diseases for which radiotherapy can be prescribed


  • Omas of the CNS

    • Schwanoma

    • Chordoma

    • Meningioma

    • Pituitary adenoma

  • AVM

  • Trigeminal neuralgia

  • Pterygium

  • Heterotopic ossification

  • Trigeminal neuralgia


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