The document discusses the commissioning and quality assurance procedures needed for radiation treatment planning systems, including performing various dose calculation and distribution tests on photon and electron beams to validate the system is working accurately before clinical use. It also describes the ongoing quality control checks that should be done such as reproducibility tests, plan verification, and in vivo dosimetry to ensure continued safe and proper system performance. Commissioning a new system typically takes months while quality assurance should involve trained staff spending about 20 minutes checking each patient's plan.
TISSUE PHANTOM RATIO - THE PHOTON BEAM QUALITY INDEXVictor Ekpo
TPR(20,10) is the recommended photon beam quality index by IAEA TRS-398 for megavoltage clinical photons generated by linear accelerators. This presentation goes through the basics of Tissue Phantom Ratio (TPR).
1.Stereotactic Radiosurgery (SRS)
SRS is a precise and focused delivery of a single, high dose of irradiation to a small and critically located intracranial volume while sparing normal structure
2.Stereotactic Body Radiation Therapy (SBRT)
SBRT is a treatment procedure similar to SRS, except that it deals extra-cranial radiosurgery
3.Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
In 2000 IAEA published another International Code of Practice.
“Absorbed Dose Determination in External Beam Radiotherapy” (Technical Report Series No. 398)
Recommending procedures to obtain the absorbed dose in water from measurements made with an ionisation chamber in external beam radiotherapy (EBRT).
TISSUE PHANTOM RATIO - THE PHOTON BEAM QUALITY INDEXVictor Ekpo
TPR(20,10) is the recommended photon beam quality index by IAEA TRS-398 for megavoltage clinical photons generated by linear accelerators. This presentation goes through the basics of Tissue Phantom Ratio (TPR).
1.Stereotactic Radiosurgery (SRS)
SRS is a precise and focused delivery of a single, high dose of irradiation to a small and critically located intracranial volume while sparing normal structure
2.Stereotactic Body Radiation Therapy (SBRT)
SBRT is a treatment procedure similar to SRS, except that it deals extra-cranial radiosurgery
3.Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
In 2000 IAEA published another International Code of Practice.
“Absorbed Dose Determination in External Beam Radiotherapy” (Technical Report Series No. 398)
Recommending procedures to obtain the absorbed dose in water from measurements made with an ionisation chamber in external beam radiotherapy (EBRT).
Updates on Electron Beam Therapy
I) Introduction
II) Central Axis Depth dose distribution
III) Dosimetric parametrics of electron beam
IV) Clinical Considerations of Electron beam therapy
A review of advances in Brachytherapy treatment planning and delivery in last decade or so, with main focus on brachytherapy for Prostate cancer, Breast cancer and Cervical cancer
Radionuclide's such as radium-226, cesium-137, and cobalt-60 have been used as sources of gamma rays for teletherapy. These gamma rays are emitted from the radionuclide's as they undergo radioactive disintegration. Of all the radionuclide's, Co-60 has proved to be the most suitable for external beam radiotherapy.
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
Updates on Electron Beam Therapy
I) Introduction
II) Central Axis Depth dose distribution
III) Dosimetric parametrics of electron beam
IV) Clinical Considerations of Electron beam therapy
A review of advances in Brachytherapy treatment planning and delivery in last decade or so, with main focus on brachytherapy for Prostate cancer, Breast cancer and Cervical cancer
Radionuclide's such as radium-226, cesium-137, and cobalt-60 have been used as sources of gamma rays for teletherapy. These gamma rays are emitted from the radionuclide's as they undergo radioactive disintegration. Of all the radionuclide's, Co-60 has proved to be the most suitable for external beam radiotherapy.
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
ENGINEERING STANDARDS AND REQUIREMENTS FOR RADIATION PROTECTION IN DESIGN OF ...IAEME Publication
The aim of this study is directed to the application of engineering standards and requirements in the design of diagnostic and/or radiation therapy units. These requirements shall be fulfilled by the architectural perspective for the protection of workers and patients without unduly limiting the beneficial practices of radiation exposure. Therefore, the different functions of ionizing radiation units must be integrated with engineering elements in specialized treatment diagnosis. The study reveals deficiencies in some analytical cases. The weakness of radiation safety in the design is evaluated compared with standard requirements. According to the engineering requirements and standards the different elements and functions in these units are rearranged.
This work was presented at the first Annual IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems (BioWireleSS) held as part of the IEEE Radio and Wireless Symposium 2011, in Phoenix, AZ.
Cancerous lung nodule detection in computed tomography imagesTELKOMNIKA JOURNAL
Diagnosis the computed tomography images (CT-images) is one of the images that may take a lot of time in diagnosis by the radiologist and may miss some of cancerous nodules in these images. Therefore, in this paper a new novel enhancement and detection cancerous nodule algorithm is proposed to diagnose a CT-images. The novel algorithm is divided into three main stages. In first stage, suspicious regions are enhanced using modified LoG algorithm. Then in stage two, a potential cancerous nodule was detected based on visual appearance in lung. Finally, five texture features analysis algorithm is implemented to reduce number of detected FP regions. This algorithm is evaluated using 60 cases (normal and cancerous cases), and it shows a high sensitivity in detecting the cancerous lung nodules with TP ration 97% and with FP ratio 25 cluster/image.
A novel CAD system to automatically detect cancerous lung nodules using wav...IJECEIAES
A novel cancerous nodules detection algorithm for computed tomography images (CT-images) is presented in this paper. CT-images are large size images with high resolution. In some cases, number of cancerous lung nodule lesions may missed by the radiologist due to fatigue. A CAD system that is proposed in this paper can help the radiologist in detecting cancerous nodules in CT- images. The proposed algorithm is divided to four stages. In the first stage, an enhancement algorithm is implement to highlight the suspicious regions. Then in the second stage, the region of interest will be detected. The adaptive SVM and wavelet transform techniques are used to reduce the detected false positive regions. This algorithm is evaluated using 60 cases (normal and cancerous cases), and it shows a high sensitivity in detecting the cancerous lung nodules with TP ration 94.5% and with FP ratio 7 cluster/image.
Artificial Intelligence To Reduce Radiation-induced Cardiotoxicity In Lung Ca...Wookjin Choi
Traditionally, radiation-induced cardiotoxicity has been studied using cardiac radiation doses rather than functional imaging. We developed artificial intelligence (AI) models based on novel cardiac delta radiomics using pre- and post-treatment FDG-PET/CT scans to predict overall survival in lung cancer patients undergoing radiotherapy. We identified four clinically relevant delta radiomics features with the AI prediction models. The best model achieved an AUC of 0.91 on the training set and 0.87 on the test set. We are a pioneering group in AI for functional cardiac imaging. If validated, this approach will enable to use standard PET/CT scans as functional cardiac imaging with good predictive AUC for OS, as well as provide automated methods to provide functional cardiac information for clinical outcome prediction AI in lung cancer patients.
Quality Assurance Programme in Computed TomographyRamzee Small
Introduction to Computed Tomography
Basic description of the components of a CT System
Introduction to Quality Assurance
Quality Assurance and Quality Control Tests in Computed Tomography base on frequency
Objective of QA/QC Test
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
1. Radiation Protection in
Radiotherapy
Part 10
Good Practice including Radiation
Protection in EBT
Lecture 3 (cont.): Radiotherapy Treatment Planning
IAEA Training Material on Radiation Protection in Radiotherapy
2. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 2
C. Commissioning
Complex procedure depending very much on
equipment
Protocols exist and should be followed
Useful literature:
J van Dyk et al. 1993 Commissioning and QA of treatment
planning computers. Int. J. Radiat. Oncol. Biol. Phys. 26: 261-273
J van Dyk et al, 1999 Computerised radiation treatment planning
systems. In: Modern Technology of Radiation Oncology (Ed.: J
Van Dyk) Chapter 8. Medical Physics Publishing, Wisconsin,
ISBN 0-944838-38-3, pp. 231-286.
3. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 3
Acceptance testing and
commissioning
Acceptance testing: Check that the system conforms with
specifications.
Documentation of specifications either in the tender, in
guidelines or manufacturers’ notes – may test against
standard data (e.g. Miller et al. 1995, AAPM report 55)
Subset of commissioning procedure
Takes typically two weeks
Commissioning: Getting the system ready for clinical use
Takes typically several months for modern 3D system
4. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 4
Some equipment required
Scanning beam data acquisition system
Calibrated ionization chamber
Slab phantom including
inhomogeneities
Radiographic film
Anthropomorphic phantom
Ruler, spirit level
5. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 5
Commissioning
A. Non-dose related components
B. Photon dose calculations
C. Electron dose calculations
(D. Brachytherapy - covered in part 11)
E. Data transfer
F. Special procedures
6. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 6
A. Non-dose components
Image input
Geometry and scaling of
Digitizer,
Scans
Output
Text information
Anatomical structure information
CT numbers
Structures (outlining tools, non-axial
reconstruction, “capping”,…)
7. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 7
Electron and photon beams
Description (machine, modality, energy)
Geometry (Gantry, collimator, table,
arcs)
Field definition (Collimator, trays, MLC,
applicators, …)
Beam modifiers (Wedges, dynamic
wedges, compensators, bolus,…)
Normalization
8. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 9
B. Photon calculation tests
Point doses
TAR, TPR, PDD, PSF
Square, rectangular and irregular fields
Inverse square law
Attenuation factors (trays, wedges,…)
Output factors
Machine settings
9. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 10
Photon calculation tests (cont.)
Dose distribution
Homogenous
Profiles (open and wedged)
SSD/SAD
Contour correction
Blocks, MLC, asymmetric jaws
Multiple beams
Arcs
Off axis (open and wedged)
Collimator/couch rotation
PTW waterphantom
10. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 11
Photon calculation tests (cont.)
Dose distribution
Inhomogeneous
Slab geometry
Other geometries
Anthropomorphic phantom
In vivo dosimetry at least for the
first patients
Following the incident in Panama, the IAEA
recommends a largely extended in vivo dosimetry
program to be implemented
11. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 12
C. Electron calculation
Similar to photons, however, additional:
Bremsstrahlung tail
Small field sizes require special consideration
Inhomogeneity has more impact
It is possible to use reference data for
comparison (Shui et al. 1992 “Verification
data for electron beam dose algorithms” Med.
Phys. 19: 623-636)
12. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 13
E. Data transfer
Pixel values, CT numbers
Missing lines
Patient/scan information
Orientation
Distortion, magnification
All needs verification!!!
13. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 14
F. Special procedures
Junctions
Electron abutting
Stereotactic procedures
Small field procedures (e.g. for eye
treatment)
IMRT
TBI, TBSI
Intraoperative radiotherapy
14. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 15
Sources of uncertainty
Patient localization
Imaging (resolution, distortions,…)
Definition of anatomy (outlines,…)
Beam geometry
Dose calculation
Dose display and plan evaluation
Plan implementation
15. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 16
Typical accuracy required (examples)
Square field CAX:
1%
MLC penumbra: 3%
Wedge outer beam:
5%
Buildup-region: 30%
3D inhomogeneity
CAX: 5%
From AAPM TG53
16. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 17
Typical accuracy required (examples)
Square field CAX:
1%
MLC penumbra: 3%
Wedge outer beam:
5%
Buildup-region: 30%
3D inhomogeneity
CAX: 5%
Note:
Uncertainties have
two components:
Dose (given in %)
Location (given in
mm)
17. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 18
Time and staff requirements for
commissioning (J Van Dyk 1999)
Photon beam: 4-7 days
Electron beam: 3-5 days
Brachytherapy: 1 day per source type
Monitor unit calculation: 0.3 days per
beam
18. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 19
Some ‘tricky’ issues
Dose Volume Histograms - watch sampling,
grid, volume determination, normalization
(1% volume represents still > 10E7 cells!)
Biological parameters - Tumour Control
Probability (TCP) and Normal Tissue
Complication Probability (NTCP) depend on
the model used and the parameters which
are available.
19. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 20
Commissioning summary
Probably the most complex task for RT
physicists - takes considerable time and training
Partial commissioning needed for system
upgrades and modification
Documentation and hardcopy data must be
included
Training is essential and courses are available
Independent check highly recommended
21. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 22
Superficial beam
HVL
Percentage depth dose (may be look up table)
Normalization point (typically the surface)
Scatter (typically back scatter) factor
Applicator and/or cone factor
Timer accuracy
On/off effect
Other effects which may affect dose (e.g. electron
contamination)
22. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 23
Quality Assurance of a treatment
planning system
QA is typically a subset of commissioning
tests
Protocols:
As for commissioning and:
M Millar et al. 1997 ACPSEM position paper.
Australas. Phys. Eng. Sci. Med. 20 Supplement
B Fraas et al. 1998 AAPM Task Group 53: QA for
clinical RT planning. Med. Phys. 25: 1773-1829
23. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 24
Aspects of QA (compare also
part 12 of the course)
Training - qualified staff
Checks against a benchmark -
reproducibility
Treatment verification
QA administration
Communication
Documentation
Awareness of procedures required
24. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 25
Quality Assurance
25. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 26
Quality Assurance
Check prescription
Hand calculation of
treatment time
26. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 27
Frequency of tests for planning (and
suggested acceptance criteria)
Commissioning and significant upgrades
See above
Annual:
MU calculation (2%)
Reference plan set (2% or 2mm)
Scaling/geometry input/output devices (1mm)
Monthly
Check sum
Some reference test sets
27. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 28
Frequency of tests (cont.)
Weekly
Input/output devices
Each time system is turned on
Check sum (no change)
Each plan
CT transfer - orientation?
Monitor units - independent check
Verify input parameters (field size, energy, etc.)
28. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 29
Treatment planning QA summary
Training most essential
Staying alert is part of QA
Documentation and reporting necessary
Treatment verification in vivo can play
an important role
30. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 31
Staff and time requirements
(source J. Van Dyk et al. 1999)
Reproducibility tests/QC: 1 week per
year
In vivo dosimetry: about 1 hour per
patient - aim for about 10% of patients
Manual check of plans and monitor
units: 20 minutes per plan
31. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 32
QA in treatment planning
The planning system
QA of the system
Plan of a patient
QA of the plan
32. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 33
QC of treatment plans
Treatment plan:
Documentation of
treatment set-up,
machine parameters,
calculation details,
dose distribution,
patient information,
record and verify
data
Consists typically of:
Treatment sheet
Isodose plan
Record and Verify
entry
Reference films
(simulator, DRR)
33. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 34
QC of treatment plans
Check plan for each patient prior to
commencement of treatment
Plan must be
Complete from prescription to set-up
information and dose delivery advise
Understandable by colleagues
Document treatment for future use
34. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 35
Who should do it?
Treatment sheet checking should involve
senior staff
It is an advantage if different professions
can be involved in the process
Reports must go to clinicians and the
relevant QA committee
35. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 36
Example for physics treatment sheet
checking procedure
1. Check prescription (energy/dose/fractionation is everything signed ?)
2. Check prescription and calculation page for consistency: Isocentric (SAD) or fixed distance (SSD) set-up ? Are all
necessary factors used? Check both,dose/fraction and number of fractions.
3. Check normalisation value (Plan or data sheets).
4. Check outline, separation and prescription depth.
5. Turn to treatment plan: Does it look ok ? Outline ? Bolus ? Isocentre placement and normalisation point ? Any concerns
regarding the use of algorithms near surfaces or inhomogeneities? Would you expect problems in planes not shown ?
Prescription ?
6. Check and compare with treatment sheet calculation page: treatment unit and type, field names, weighting, wedges,
blocks, field size (FS), focus surface distance (FSD), Tissue Air Ratio (TAR) (if isocentric treatment) - is this consistent
with entries in treatment log page?
7. Electrons only: …
8. Photons only: …
9. Check shadow tray factor, wedge factor. Are any other attenuation factors required (e.g. couch, headrest, table tray...) ?
10. Check inverse square law factor (in electron treatments: is the virtual FSD appropriate?)
11. Calculate monitor units. Is time entry ok ?
12. Check if critical organ (e.g. spinal cord, lens, scrotum) dose or hot spot dose is required. If so, is it calculated correctly ?
13. Suggest in vivo dosimetry measurements if appropriate. Sign calculation sheet (if everything is ok).
14. Compare results on calculation page with entries in treatment log.
15. Check diagram and/or set up description: is there anything else worth to consider ?
16. Sign top of treatment sheet (specify what parts where checked if not all fields were checked).
17. Contact planning staff if required. Sign off physics log book.
36. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 37
Example for physics treatment sheet
checking procedure
1. Check prescription (energy/dose/fractionation is
everything signed ?)
2. Check prescription and calculation page for
consistency: Isocentric (SAD) or fixed distance (SSD)
set-up ? Are all necessary factors used? Check
both,dose/fraction and number of fractions.
3. Check normalisation value (Plan or data sheets).
4. Check outline, separation and prescription depth.
5. Turn to treatment plan: Does it look ok ? Outline ?
Bolus ? Isocentre placement and normalisation point ?
Any concerns regarding the use of algorithms near
surfaces or inhomogeneities? Would you expect
problems in planes not shown ? Prescription ?
37. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 38
Example for physics treatment sheet
checking procedure (cont.)
6. Check and compare with treatment sheet calculation page:
treatment unit and type, field names, weighting, wedges,
blocks, field size (FS), focus surface distance (FSD), Tissue
Air Ratio (TAR) (if isocentric treatment) - is this consistent with
entries in treatment log page?
7. Electrons only: …
8. Photons only: …
9. Check shadow tray factor, wedge factor. Are any other
attenuation factors required (e.g. couch, headrest, table
tray...) ?
10. Check inverse square law factor (in electron treatments: is the
virtual FSD appropriate?)
11. Calculate monitor units. Is time entry ok ?
12. Check if critical organ (e.g. spinal cord, lens, scrotum) dose or
hot spot dose is required. If so, is it calculated correctly ?
38. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 39
Example for physics treatment sheet
checking procedure (cont.)
13. Suggest in vivo dosimetry measurements if
appropriate. Sign calculation sheet (if everything is
ok).
14. Compare results on calculation page with entries in
treatment log.
15. Check diagram and/or set up description: is there
anything else worth to consider ?
16. Sign top of treatment sheet (specify what parts
where checked if not all fields were checked).
17. Contact planning staff if required. Sign off
physics log book.
39. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 40
Treatment plan QA summary
Essential part of departmental QA
Part of patient records
Multidisciplinary approach
41. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 42
Did we achieve the objectives?
Understand the general principles of
radiotherapy treatment planning
Appreciate different dose calculation
algorithms
Be able to apply the concepts of optimization
of medical exposure throughout the treatment
planning process
Appreciate the need for quality assurance in
radiotherapy treatment planning
42. Radiation Protection in Radiotherapy Part 10, lecture 3 (cont.): Radiotherapy treatment planning 43
Overall Summary
Treatment planning is the most important step
towards radiotherapy for individual patients -
as such it is essential for patient protection as
outlined in BSS
Treatment planning is growing more complex
and time consuming
Understanding of the process is essential
QA of all aspects is essential