Test 3 Flashcards
Heterogenous group of diseases in blood
Leukemia
4 subtypes of leukemia
Acute lymphoblastic leukemia (ALL)
Acute myeloid leukemia (AML)
Chronic lymphocytic leukemia (CLL)
Chronic myeloid leukemia (CML)
Most common leukemia in kids; radiation therapy (RT), chemo, and bone marrow transplant (BMT)
Treatment of choice: BMT
Acute lymphoblastic leukemia (ALL)
4 RT treatment techniques for ALL
Total body irradiation (TBI) used in combination with BMT to prevent rejection
CNS technique
Helmet field/whole brain prophylactic treatment to cover meninges
Testicular field: leukemia cells track to testicles (“sanctuary”)
Testicular field dose
400 cGy in 1 fraction and TBI
Cranial-spinal irradiation (CSI) helmet field (right and left laterals) and spinal fields treat CSF
CNS technique
Most common leukemia per ACS; same in all ages, slight increase over 50
RT, chemo, and BMT (TBI)
Treatment of choice: BMT
Acute myeloid leukemia (AML)
Was the most common leukemia in US for years, usually elderly patients that can live awhile with disease
Optimal treatment unknown; palliative RT for local masses and involved lymph node (LN) and/or spleen
Chronic lymphocytic leukemia (CLL)
Associated with Philadelphia chromosome, middle age around 55
RT for spleen or TBI, chemo, and transplant
Treatment of choice: BMT
Chronic myeloid leukemia (CML)
2 types of TBI’s
High dose
Low dose
High dose TBI dose for transplant
1000 cGy in 1 treatment
2 types of high dose TBI’s
Single
Fractionated
Single and fractionated high dose TBI dose
Single: 550 cGy at 275 cGy a side and 400 cGy/min
Fractionated: 1225 cGy in 7 fractions, about 175 cGy per treatment
Low dose TBI dose
5-15 cGy 2-5 times a week to 50-150 cGy, 10 cGy/min
TBI lung dose less than _______ cGy; pneumonitis at _______ cGy
800 cGy
1400 cGy
Chemo drug that gives same results as TBI
Methotrexate
Half body treatment
Hemibody irradiation (HBI)
Upper and lower doses for HBI and time between upper and lower treatment
Upper: 600 cGy (lower because of lungs)
Lower: 800 cGy
Time: 2-4 weeks between treatments
Produces hormones under complex feedback-control mechanisms that affect various functions to meet ongoing metabolic needs and stresses of the organism; rare diseases
Endocrine system
Master regulatory gland of the endocrine system
Pituitary gland
Gland that regulates metabolism
Treatment: surgery, RT (EBRT and brachytherapy with iodine-131), and hormonal therapy; responsiveness dependent on histology
Thyroid cancer
Thyroid dose
50-60 Gy in 7 weeks, 180-200 cGy per fraction
Iodine-131 for anaplastic thyroid disease dose (radioresistant), activity, and 2 forms
Dose: high dose at 60 Gy
Activity: 50-100 mCi (don’t stay in hospital with less than 100 mCi)
2 forms: liquid and pill (traces to thyroid)
Primary treatment goal: normalize pituitary hormonal function or relieve local compressive or destructive effects of the tumor; accomplished surgically, RT, medically, or in combination
Post-op RT controversial but can stop recurrence; RT for patients who don’t fit surgery medically or refuse
Protons (rapid fall-off), SRS, IMRT
Use 6-10 or more to get good dose coverage
SRS margin: 0.5-1 cm
Pituitary tumors
IMRT for pituitary tumors 2 patient positions, fields, field size (FS), and margins
2 positions: tuck chin to avoid eyes; if patient can’t tuck chin, do vertex, kick couch 90 degrees, and turn collimator
Fields: 2 laterals and AP (dose pushes up towards an unopposed field; use wedge with heel to AP)
FS: 5x5 or 6x6 cm
Margins: 1.5 cm
Pituitary dose and dose for tumors 2 or more cm
Dose: 180-200 cGy per treatment, 4500-5400 cGy total dose range
2 cm or larger tumor: up to 5400 cGy
7 hormones secreted by the pituitary
Growth Prolactin Thyroid-stimulating Follicle-stimulating Luteinizing Melanocyte-stimulating Adrenocorticotropic
Hormone that controls body growth
Growth hormone
Hormone that initiates milk production
Prolactin
Hormone that controls thyroid gland
Thyroid-stimulating hormone
Hormone that stimulates egg and sperm production
Follicle-stimulating hormone
Hormone that stimulates other sexual and reproductive activity
Luteinizing hormone
Hormone that relates to skin pigmentation
Melanocyte-stimulating hormone
Hormone that influences the action of the adrenal cortex, stress response
Adrenocorticotropic hormone
2 cells of the pituitary gland
Acidophil
Basophils
Cell that secretes growth hormone and prolactin
Acidophil
Cells that secretes everything else
Basophils
Located anterior, superior and medial to kidneys; on superior pole of kidneys, surround outer part
Surgery is treatment of choice; RT increases local control a little but is usually used as adjuvant to surgery or for palliation
More common in left than right
Adrenal cortex tumors
Adrenal cortex tumor dose for inoperable patients and for adrenal mets
Inoperable: 50-60 Gy in 5-7 weeks; 1 large field at 40 Gy and smaller boost
Mets: palliative 30-40 Gy in 2-3 weeks
Malignancies in thorax; most common in lung, pankos tumor in apex/high in lung
Esophageal thymomas, germ cell tumors, mets, etc.
All modalities together or alone; RT for LN’s (PET)
High doses, very good immobilization devices from head to mid-thigh with arms above head
AP/PA fields and laterals if needed
Patients with lung cancer require treatment of primary tumor, and hilar, mediastinal and supraclavicular LN’s
Treat AP/PA until cord tolerance reached then obliques and laterals; boost fields smaller
Multiple field design variations due to volume (limit volume of structure receiving dose) and dose limitations to certain structures
Shielding, MLC’s, IMRT, VMAT, etc.
Can monitor spinal cord dose; CT to define depth
Respiratory system disease
Tumor originating from epithelial cells of the thymus which plays an important role in kids’ immunity
Occurs in younger patients, surgery is treatment of choice
RT when tumor unresectable; IMRT, VMAT, and tomotherapy offer conformal isodoses
Thymoma
3 routes of spread of respiratory system diseases
Direct
Lymphatic
Hematogenic through blood
Tumor reproduces and grows in size and mass, altered surface enzymes grow into surrounding structures; direct or local extension
Direct spread
Cancer cells enter LN system
Lymphatic spread
2 ways of lymphatic spread
LN chain (LN to LN) Enters LN and gains access to blood/circulatory system
7 common mets side of respiratory system disease
Liver Adrenals Bone Brain Cervical LN's Kidneys Contralateral lung
Downfall to volumetric arc therapy (VMAT) versus IMRT for lung treatment
More lung treated with VMAT
When is lung disease treatment definitive or curative versus palliative?
Definitive or curative without extrathoracic spread, with = palliative
Why may cord dose be higher towards cephalic margin?
Thinner part
How did PET/4DCT change the treatment of lung cancer?
4D = time, tracks tumor motion; lead to more arc/IMRT treatments
AP/PA might miss part of lung tumor so do _________; _________ increase dose to both already compromised lungs, thicker part
Obliques; laterals
Difficulty breathing except in upright position, can’t lay flat
Orthopnea
Dose for SVC syndrome oncologic emergency and time it takes to relieve symptoms
Dose: 250-400 cGy in 2-3 fractions (high)
Time: relief from symptoms in 2-3 weeks but no long-term survival
2 reasons boost/shrinking fields are done
Decrease when tumor decreases in size
Reduce dose to OARs
Organ that has lower dose tolerance than what’s needed to treat tumor
Critical structure
Spinal cord, heart, lung, and esophagus TD’s
Spinal cord: 4500-4700 cGy
Heart: 4000 cGy
Lung: 1750 cGy
Esophagus: 5500 cGy
When treating near heart, consider when ___% of heart receives ___-___ Gy; can see pericarditis and pancarditis
60%
45-55 Gy
Inflammation of membrane surrounding heart
Pericarditis
Inflammation of entire heart
Pancarditis
Lung = pneumonitis; fibrosis greater than ___% volume exposure
40%
Volume of lung receiving 2000 cGy, want it at 20-30%
V20
Need SSD and thickness at point; lateral horns from flattering filter lead to high doses
Off-axis points
Percent of lung cancer cases that are large cell non-oat/non-small cell lung cancer (NSCLC)
88%
Palliative dose for NSCLC
45 Gy in 18 fractions
Right lung has ___ lobes, left has heart so ___ lobes
3, 2
Fields, dose, and 2 boost doses for NSCLC where surgery is not possible
AP/PA obliques up to 5000 cGy and 1 boost of 1000 cGy = 60 Gy in 6-7 weeks to tumor or regional LN’s with positive disease
2nd boost to primary tumor of 500-1500 cGy = 65-7000 cGy total
Preoperative dose for NSCLC where surgery is possible (early T’s, no nodes, M1-M2)
30 Gy in 10 fractions, no improvement in survival
Postoperative dose (initial and boost) for NSCLC where surgery is possible (early T’s, no nodes, M1-M2)
60-66 Gy, 200 cGy per fraction
Initial dose of 5000 cGy with boost of 1000-1500 cGy to volume with disease = 60-66 Gy
2 sources for brachytherapy for postoperative for NSCLC; permanant interstitial catheter implants
HDR iridium
LDR iodine-125
20% of lung cancers; poor prognosis, more aggressive
High mets rate, rapid proliferation results in a greater initial response to radiation
Chemo and RT
Prophylactic brain irradiation because it commonly metastasizes to brain
Small/oat cell lung cancer
Dose to primary tumor, residual tumor, and total dose per fraction for small/oat cell lung cancer
4000 cGy in 6 weeks to primary tumor and 1000 cGy to residual tumor = 45-60 Gy in 180-200 cGy per fraction
Thymoma dose per fraction and dose for positive margins
Dose: 45-50 Gy at 180-200 cGy per fraction
Positive margins: 54-60 Gy
Connection between two tubular structures by surgery or pathology, creates weakness
Anastomosis
Past _____ cGy to trachea, fistula can form
4500 cGy
Trachea dose, boost, and borders
50-60 Gy (over 60 Gy gives best results but can result in complications)
Lower border at carina, initially give 4500 cGy at lower carina and a boost to 50-60 Gy
Tumors along chest wall; ex: recurrent breast cancer (tangents), connective tissue, etc.
Size and location affect field arrangement; ex: electrons if superficial
Soft tissue tumors
Lymphoma dose
4500 cGy
