Principles and Practice of Radiation Therapy

Principles and Practice of Radiation Therapy
Chapter 8 Treatment Procedures Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation Treatment Delivery
Radiation therapy is an essential component of quality oncologic care, consisting of Planning Simulation Administration of prescribed course of radiation therapy Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation Therapist Contribution
Attention to precision and reproducibility in simulation and treatment delivery Deliver radiation therapy treatment Monitor and operate sophisticated radiation-producing equipment Maintain detailed treatment records Attending to the physiologic and psychological needs of the patient Patient care skills and knowledge Legal considerations Clinical judgment Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Task Analysis of Treatment Procedures
Refer to Box 8-1 on page 159 of the textbook to review an 18-step task analysis process. Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation Oncology Record
Separate from hospital chart Remains in the radiation oncology department Legal record of patient’s radiation treatments Completeness Organization Legibility Each page must identify the patient by name and identification number Patient’s record privacy Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.
Informed Consent Before receiving treatment, patients must be informed Explanation of their status (diagnosis/staging) Treatment alternatives Consequences associated with/without treatment Documented informed consent Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Response Treatment monitored and recorded throughout and following completion of treatment Observations documented Physicians, nurses, therapists Weekly assessment Physician visits, weight, blood counts Care activities Medication, nutritional advise, psychosocial intervention Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Electronic Medical Records (EMRs)
These systems monitor and document experiences of the patient in the therapy department Information stored in a centralized database and access limited only by networking capabilities of the facility and to each member of the radiation oncology staff Most are limited to clinical charting and radiation treatment details Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Electronic Medical Records (EMRs)
Comprehensive EMR may be all inclusive Schedules Communications from referring physicians External diagnostic facilities Reimbursement information Digital diagnostic and planning images between computerized systems such as computed tomography (CT), image registration, and fusion Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Electronic Portal Imaging Devices (EPIDs)
Kilovolt x-ray source mounted to the gantry converts x-ray information to digital information that can be displayed as an image on a computer screen Electronic imaging systems produce real-time images of treatment volumes, and computer manipulation of digital information enhances visualization Improves treatment planning and delivery and, therefore, treatment accuracy Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Verify and Record Aid in the accurate and efficient delivery of treatment to patients Validate parameters from the treatment plan for treatment machine setup and delivery Machine settings are compared daily with the most recently prescribed for each field Prevent initiation of the treatment beam if settings vary outside the specified tolerance range Verification and record (V&R, R&V, or RV) Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Machine Parameters Monitored by V&R
Monitor units Gantry position Collimator aperture and rotation settings Table position Arc vs. fixed treatment Use of beam modifiers Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Verify and Record Verification beyond the capabilities of the treatment machine: Patient identification Secondary equipment attached to, but not integrated with, the machine itself Selection of fields Auto-setup of treatment parameters Auto-sequencing of treatment fields Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Quality Assurance (QA)
Activities and documentation performed with the goal of optimizing patient care Ensures accuracy of delivery of treatment Reviewing patient record Monitoring the functioning of equipment Maintaining accuracy in reproducing setup Monitoring changes in patient status Maintaining complete and accurate treatment record Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Quality Assurance Communication is key for QA Radiation oncology team Radiation oncologist, therapist, dosimetrist, nurse, and staff Weekly chart reviews Maintaining open lines of communication Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Quality Assurance Programs
Requirements for patient chart Patient’s history Diagnostic evaluation Rationale for treatment Detailed description of treatment plan Documentation of informed consent Documentation of treatment delivered *All information is required before treatment begins Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Patient Oncology Chart
Regular review of chart by each member of the treatment team Checklists of role responsibilities and schedules for review ensure completeness of chart reviews and are maintained in the chart, written or electronically Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation Therapist Responsibilities
Weekly chart reviews Monitoring verification of source-skin distance (SSD) Diode measurements Status of physics and oncologist review Frequency of verification imaging Accuracy of fractional and cumulative dose Completion of physics chart checks Verify reimbursement charges submitted Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Session Preparation
Information needed before reproduction of the course of treatment: Patient identification (photograph) Signed prescription (by oncologist only) Detailed patient- and equipment-position information Dosimetric plans Calculations Treatment history Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Record Treatment record documents Delivery of treatments, recording Fractional and cumulative doses Machine settings Verification imaging Ordering and implementation of prescribed changes Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation Prescription
Radiation delivered only under direct order of radiation oncologist with signed prescription Anatomic site (diagnosis/stage) Total radiation dose (5000 cGy) Fractionation - individual treatment dose (200/day) Protraction - time period over which treatment will be given (5 weeks) Treatment technique (number and orientation of treatment fields) Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Other Information Information that may be in prescription and/or specified in record Beam energy Portal sizes Entry angles Beam modifier Patient positioning Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Changes in Prescription or Treatment Plan
Changes may be made any time during treatment; therapist is responsible for ensuring implementation Physician’s signature and date must accompany any changes Electronic charting – passwords protect the security of the physician’s electronic signature Changes may include Fractionation Dose (requires a review of plan) Addition or deletion of blocks or bolus Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Radiation Therapist Responsibilities
Knowledge of treatment effects with radiation Tumor-lethal doses Limits of radiation tolerance to normal tissue Knowledge of treatment plan and changes in the course of treatment Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Plan Description/Reference Images
Treatment plans One or more treatment fields designed to maximize the dose to tumor and minimize the dose to normal and surrounding structures Dose distribution Calculations prepared by dosimetrist Field sizes, beam modifiers, and treatment depths identified during treatment setup Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Field Treatment field (portal) Volume of tissue exposed to radiation from a single beam of radiation Each field is assigned an identifier and name indicating the prescription site and beam direction (see Figure 8-1 on page 161 of the textbook) Field identifier is assigned only once to each patient; new fields progress sequentially as added Subscript letters, numbers, or prime marks may be used to denote changes in field size, shape, or isocenter from the original field Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Field Treatment field Field description specifies field size, orientation of beam entry in patient coordinates, and beam modifiers to be used Treatment field dimensions are stated width by length in centimeters Consistency must be maintained when both paper and electronic methods are used Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Setup Instructions Treatment field descriptions Beam’s eye view (BEV) - irradiated area and treatment field shape and orientation as it passes through the patient Descriptive information Diagrams and/or photographs illustrating patient positioning and immobilization Surface landmarks Illustrating isocenter and treatment target volumes Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Record Before initiating treatment, the therapist performs a review of the treatment record to date for completeness and accuracy Records for individual treatment identify Date of treatment Treatment number Elapsed days Daily fraction Cumulative dose Notation of any change (e.g., verification imaging) Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Verification Images Taken on treatment unit with patient in treatment position Compared with reference images Clinical acceptance or changes are generated Modifications made and documented, if necessary, before treatment Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Localization Localization Geometric definition of the position and extent of the tumor or anatomic structures by reference of surface marks that can be used for treatment setup purposes Tumor volume and critical normal structures are localized using electronic portal filming, radiographic filming, and CT imaging Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Verification Image Accessories
Imaging requires attention to equipment and technique Consideration of accessories in imaging Type of film (sensitivity) Type of cassette (hard or soft) Magnification markers Radiopaque indicators Graticule (bb tray or dot tray) Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room Linear accelerator – used to facilitate the precise application of therapeutic radiation beams to well-defined treatment volumes Rotates around a fixed point – isocenter Isocenter is the point of intersection of the three axes of rotation (gantry, collimator, and base of couch) Isocentric mounting facilitates the reproducibility of complex treatment plans Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room Treatment room is engineered around isocenter Accessibility to treatment accessories Movement by therapist around this focal point Shelves and storage cabinets around perimeter Organized system for custom block storage facilitates quick retrieval Maintenance of treatment room – part of the department QA program Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room: Lasers
Points or lines of light from three or four sources along vertical and horizontal planes, intersecting at the treatment machine isocenter Project from walls, ceiling, or opposite gantry Provide visual reference to the location of isocenter, facilitating alignment of machine coordinates with external patient landmarks to align the accelerator’s isocenter with its planned position with the patient Red or green helium neon (HeNe) used in lasers Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room: Lighting
Standard lighting Safety of patients entering and exiting the room Dim lighting For visualization of lasers and field light, for patient positioning and treatment setup When treatment is in progress, full lights enable patient to be watched on monitors during treatment Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room: Preparation
Preparation for treatment setup and before patient entering room Field size Gantry Collimator Table (window option) Accessories Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room: Universal Precautions
Cleaning All treatment tables and accessories cleaned with disinfectant cleaners after each use Linens replaced for each patient Universal precautions practiced with each patient Universal precautions are methods of infection control in which any human blood or body fluid is treated as though it were known to be infectious Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room: Position and Immobilization Devices
Positioning/Immobilization Treatment Devices Sponges Blocks Casts Wedges Masks Bolus Bite blocks Compensators Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

The Patient: Identification
Identification photograph In treatment chart Wrist bracelet Wrist bracelet for inpatient Identification card for outpatient Bar-coding system Used with electronic charting Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Patient Preparation Radiation therapist-patient relationship Treatment ranges from 2-6 weeks Therapists have most frequent contact with patient (daily) Daily observations may indicate needs of patient for social services or changes in disease state Patient entrusts therapist Encourages confidence and cooperation Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Patient Communication
The radiation therapist demonstrates respect for the patient through clear communication of directions at a level understandable to the patient Cultural sensitivity and linguistic competency Age Mental status Native language Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Patient Communication
Patient counseling from start of treatment Proper maintenance of skin marks General skin care Nutrition guidelines Acute radiation reactions (during treatment) Therapist responsible for Assessing patient’s verbal and observable responses Skin reactions, weight change, changes in demeanor Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Patient Position, Isocenter, and Field Placement
Precision in the reproduction and immobilization of the treatment position, stability of surface landmarks, and exactitude in alignment of the patient with these references contribute greatly to variation in treatment delivery and represent the greatest obstacle to the application of advances in treatment planning Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Patient Positioning The treatment description in the chart is used to reproduce a position consistent with that prescribed at simulation Drawings Photographs Explanations Tools Measurements Comfort of patient also needs to be considered Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Localization Landmarks
Natural anatomy Artificial fiducial markers Palpable anatomic landmarks Tattoos Semipermanent marks Permanent ink markers Paint pen Clear patient-sensitive tape or markers Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Positioning Isocenter
Treatment volume alignment with machine most often begins with a process of triangulation Isocenter – three point coordinate setup Machine isocenter – point of horizontal and vertical lasers Coordinate system (surfaces such as breast or axilla, older or obese patients, sloping surfaces, irregular surfaces) Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Verification Imaging (Setup)
Verification of isocenter is accomplished by comparing a pair of planar images with corresponding reference images Stereoscopic Orthogonal Coplanar Online Image-guided radiation therapy (IGRT) Interfraction Intrafraction Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Beam Position and Shape
Standard collimation systems allow customizing of standard fields into a square or rectangle. However, individuals and tumors do not grow into squares or rectangles. Further field shaping is required for most treatments and is accomplished by custom or standard blocking Multileaf collimators Blocks Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Multileaf Collimators (MLCs)
Linear accelerators with MLC systems customize field shapes using “jaws” that have been sliced into a series of opposing leaves Each leaf ( leaves) is positioned independently, producing a variety of treatment field shapes Customization of treatment volume Complexity of MLCs requires verification and record systems to be in place Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Blocks Shielding blocks Used to shape photon or electron fields Rest on a plastic tray Required thickness based on energy Spent uranium, lead, lead alloys Beam attenuation of less than 5% of original beam May be useful for emergency treatment or until customized shield or MLC plans are created Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Limitations of Blocks Divergent/nondivergent Alloy Cerrobend is composed of bismuth (50%), lead (26.7%), tin (13.3%), and cadmium (10%) and has a melting point of 165° F. Cadmium and lead are toxic. Electron contamination The interaction of the photon beam with material produces scatter electrons that contaminate the photon beam and produce increased skin dose for patient. Low-energy electrons are absorbed in 15 cm of air; therefore, all beam-shaping and modification devices for photon beams must be secured a minimum of 20 cm from the surface of the patient Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Portal Imaging Portal images Taken at start of treatment Frequency of portal imaging based on department policy and professional judgment Weekly portal imaging for radical cases Unstable localization landmarks Proximity of treatment volume to critical structures Daily portal imaging with EPID Film based: single or double exposure Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Electron Beam Superficial treatment Physical characteristics of electron beams: Rapid dose build-up Area of uniform dose deposition Rapid dose fall-off Less penetration Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Assessment and Acceptance of Treatment Parameters
Final review of treatment setup Patient-monitoring systems Audio: two-way communication with patient Visual: two cameras viewing patient during treatment Console Provides information to therapist regarding the status of the treatment unit Malfunctions reported to NRC/FDA Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Delivery Beam on and beam off Initiation of beam requires turning a key or pressing a switch Treatment interruptions Pressing beam-off key Turn operation key to “off” position Opening door to treatment unit Emergency off Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Common Treatment Techniques
Parallel opposed portal (POP) Tangential fields Four-field technique Wedge-pair technique Conformal therapy (six or more fields) Arc therapy Stereotactic radiosurgery (SRS) Fractionated stereotactic radiation therapy (SRT) Total-body irradiation (TBI) Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Intensity-Modulated Radiation Therapy (IMRT)
Goal of radiation treatment planning: Deliver an evenly distributed radiation dose to the target volume while minimizing the dose to surrounding normal tissue Conventional and conformal treatment plan IMRT MLC Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Conventional vs. IMRT Conventional and conformal plans accomplish evenly distributed dose to the target volume while minimizing the dose to surrounding normal tissue. A relatively uniform dose is delivered to structures in the beam path. IMRT delivers nonuniform exposure across the BEV using a variety of techniques and equipment. As radiation intensity is varied (modulated) across the exposed field, critical structures are protected. Areas of low dose in the target from one field are compensated by larger doses delivered through another gantry angle that does not intersect the protected structure. Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

IMRT Requirements A highly physics-intensive program Specially equipped accelerators and/or MLC units Inverse treatment planning Specialized dose measurement and QA tools Record and verify systems Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Treatment Room Maintenance/Cleanliness
Treatment room maintenance is critical to safe and efficient patient care and treatment delivery. Therapist must monitor performance of treatment unit: Accessories: Check for signs of wear or damage Supplies of nonreusable or disposable items Positioning or immobilization devices Sufficient shelf and cabinet space Copyright © 2010 by Mosby, Inc., an affiliate of Elsevier Inc.

Principles and Practice of Radiation Therapy

Similar presentations

Presentation on theme: "Principles and Practice of Radiation Therapy"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Principles and Practice of Radiation Therapy

Similar presentations

Presentation on theme: "Principles and Practice of Radiation Therapy"— Presentation transcript:

Similar presentations

About project

Feedback