Workbook Radiobiology PDF: Cell Survival, Radiotherapy, and Tumor Control

Certainly! Here is the converted text from the images into a structured markdown format: ```markdown No.: Date: # **WORKBOOK RADIOBIOLOGY** **KHAIRIN ADRIANA BINTI KHAIRUL ANUAR** **(A213147)** ## A MOLECULAR AND CELLULAR RADIOBIOLOGY ### 1) Comparison of Cell-Survival Curves for Neutron and X-r...

Certainly! Here is the converted text from the images into a structured markdown format: ```markdown No.: Date: # **WORKBOOK RADIOBIOLOGY** **KHAIRIN ADRIANA BINTI KHAIRUL ANUAR** **(A213147)** ## A MOLECULAR AND CELLULAR RADIOBIOLOGY ### 1) Comparison of Cell-Survival Curves for Neutron and X-ray (250keV) radiation The image is a graph comparing the cell survival curves for Neutron and X-ray (250keV) radiation. The y-axis represents the survival fraction (log scale) and the x-axis represents the dose in Gray (Gy). There are two curves on the graph, one for X-ray (250keV) and the other for neutron radiation. The x-ray cure has a shoulder, while the neutron curve is more linear. * **X-rays (250 Kev):** As a low LET radiation, x-rays cause sublethal damage at lower doses which allow the cells to repair the damage. The shoulder on the curve reflects this repair ability and the curve becomes steeper as the dose increases with little repair at higher doses. * **Neutrons:** Neutron radiation is high LET and leads to more direct damage to the cells, which makes it harder for cells to repair damage. The absence of a shoulder indicates repair is less effective at low doses and the damage caused by neutrons remains significant even at higher doses. --- No.: Date: ### 2. Table Differentiating between Apoptosis and Necrosis | Feature | Apoptosis | Necrosis | | :-------------------- | :--------------------------------------------------------------- | :------------------------------------------------- | | Definition | A programmed process of cell death | Uncontrolled cell death due to injury | | Cause | Internal or external regulatory signals | Physical or chemical damage | | Cell morphology | Cell shrinkage and chromatin condensed | Cell swelling and membrane rupture | | Energy Requirement | ATP-dependant | No energy required | | Inflammation | No inflammation | Causes inflammation | ### 3. Linear Quadratic model The image is of a graph plotting the cell survival curve using a linear quadratic model. The y-axis represents surviving fraction (log) and the x-axis represents radiation dose (Gy). There are two curves on the graph, one for densely ionizing radiation and the other for sparsely ionizing xrays. --- NO.: ### 3. The provided graph shows the Linear Quadratic Model which describes the survival of cells after radiation exposure. The curvature of the survival curve is dermined by $\alpha$/$\beta$ ratio which represents the linear and quadratic contributions to all killing respectively. The survival fraction ($SF$) is mathematically expressed as $SF = e^{(-\alpha D+\beta D^{2})}$ where $D$ is the radiation dose in Gray (Gy). The curve demonstrates two types of radiations which are sparsely ionizing radiation and densely ionizing radiation. For sparsely ionizing radiation, the curve displays a shoulder at lower dases, indicating that sub-lethal damage ean be repaired AS the dose increases, the curve steepens and becomes more linear, reflecting more extensive cell damage. In contrast, the curve for densely ionizing radiation is almost linear from the start au this type of radiation causes significant and irreparable damage, leaving little room for sub-lethal damage repair ### 4. Oxygen Effects in radiation response The image is a line graph plotting surviving fraction on the y axis against radiation dose on the x axis for both aerobic and hypoxic tissues. The hypoxic line decreases less sharply whereas the aerobic line decreases sharply. --- 4. The graph shows the effect of oxygen radiation response by comparing cell survival curves under aerobic coxygen-rich) and hypoxic (low-oxygen) conditions as a functions of radiation dose Under aerobic conditions, the survival fraction decreases more rapidly with increasing radiation dose. This indicates that cells are more sensitive to radiation when oxygen is present, as oxygen enhancer radiation-induced damage. On the other hand, under hypoxic atts conditions, the survival fraction decreases more slowly increasing radiation dose. Folls more resistant to radiation damage in Lypoxic conditions. --- ## B. TUMOUR RADIOTHERAPY ### 1. Diagram of PTV, GTV, CTV and ITV and their definitions The image shows a series of concentric circles, labeled respectively as GVT, CTV, ITV, PTV and OAR. * **GTV (Gross Tumour Volume):** The visible or palpable tumour mass that can be seen on imaging or physically left. It represents the tumour's extent as detected * **CTV (Clinical Target Volume):** The volume that includes the GTV plus any subclinical microscopic disease that might present but is not visible. * **ITV (Internal Target Volume):** A volume that accounts for internal organ motion during respiration or other movement * **PTV (Planning Target Volume):** The CTV with an additional margin to account for uncertainties in treatment delivery such as organ motion and setup errors. * **AR (Organs at Risk):** Healthy tissues or organs that should be protected as much as possible during radiotherapy. --- No.: Date: ### 2. Surviving Fractions for single and Multiple Fractions Radiotherapy. The image included a line graph plotting the radiation dose in cGy (x axis) against the surviving fraction (y axis). There are two curves plotted: one for single fractions and one for multiple fractions. The graph shows the surviving fraction of a cell culture a single fraction exposure of 800cGy and multiple fraction exposure multiple fraction exposure of 200CGy delivered in four sessions. It is evident that the surviving fraction is higher with the multi-fraction exposure eventhough the total cumulative dose is the Same. This difference occurs due to sub-lethal damage repair (SLDR) in cells between each fraction which allows for pantial recovery, Consequently, multiple smaller fractions result in greater cell survival companed to a single lange fraction. --- No.: Date: ### 3. Graph of tumour Control Dose 50% (TCb50) The image shows a graph of tissue response ti treatment (y axis) plotted against the radiation dose (Gy) on the x axis. The graph illustrates the percentage of tissue response to tumour treatment at different radiation doses. It shows that 50% tumour response or control is achieved with 9 a radiation bate dose of 56 Gy. Therefore, the 70050 an the dase requined fon 50% tumour control is 56 Gy. ### 4. Definition of the following terms: * **(a) Total Control:** All clonogenic calls within a tumour that capable of reproducing and causing recurnence after radiotherapy are completely inactivated. * **(b) Local Recurrence:** A tumour reappears at or near its original site after treatment. This suggest that some cancerous cells remained and began to grow again after the initial treatment. * **(ex) Metastasis:** Process by which cancer cells spread from the primary tumour to distant parts of the body forming secondary tumours in organs an tissues --- No.: Date: * **(d) Regional control:** : Prevention of career growth or spread within the nearby tissues, lymph nodes on Structures surrounding the primary tumour. It ensures that the cancer remains contined to the local region. * **(e) Tumour Remission:** A period during which the tumour Shrinks significantly or dissappears altogether asq result of effective treatment. ### 5. Difference between Perfusion-Limited and Diffusion-Limiten Hypoxia The cause of perfusion-limited hypoxia is inadequate blood to the tissue. The oxygen delivery to tissues is restricted supply due to poor blood flow even if oxygen is sufficiently present in the blood. While, diffusion-limited hypoxia caused by poor oxygen diffusion from the capillaries into the tissues. Even if blood flow is adequate, oxygen had difficulty diffusing into the tissues because of a barrier. Next, the oxygen delivery for perfusion-limited hypoxia is low because of poor blood flow while oxygen delivery Pon diffusion-limited hypoxia is good but oxygen can't reach tisones- easily. Furthermore, increaving oxygen oupply when perfusion limited hypoxia, can help resolve hypoxia as More oxygen reaches the tissue through improved perfusion, on the other hand, increasing oxygen supply during diffusion limited hypoxia, will have little effect because the issue lies in the diffusion process, not the oxygen deliveny- --- 6. Fractionation reducing tumour hypoxia The image shows a series of labelled diagrams depicting the fractionation process and the reduction of tumour hypoxia. * Hypoxic alls at the anter of tumor get reoxygenated which occurs during a fractionated course of treatment, making them more radiosensitive to subsequent dover of radiation. --- 6 7. Difference of yumour control for Jumours with ditfer radiosensitivit The image is a line graph plotting the extra dose to control proliferation against time. There are labelled lines for tumors which are both highly radiosensitive and highly radioresistant The graph shows tumour control probability percentage for different tumour sensitivities at various doses. Tumour that is highly sensitive like lymphoma, can be controlled effectively with low nadiation doses, often below 60 Gy because their cells are More easily damaged by radiation. Revistant tumors like thyroid cancer nequines higher doses i upto 120 Gy or mone to control but even with these hi higher doses, they ane are harder 7 treat effectively. --- ## C NORMAL TISSUE RESPONSE TO RADIOTHERAPY ### 1. Table differentiating between Serial and Parallel Structures | Characteristic | Serial | Parallel | | :------------------- | :------------------------------------------------------ | :------------------------------------------------------- | | Function | One key function (damage affects the whole organ) | Multiple functions.(damage to one part doesn't affect the whole organ) | | Radiation Sensitivity | Sensitive to radiation | Can tolerate more radiation | | Effect of Damage | Serious impact even with small damage | Damage can be tolerated with out major loss of function | | Recovery | Poor recovery | Better recovery | | Radiation dose | Uniform dose | Can handle uneven doses | | Examples | Spinal cord, Brainstem | Lungs, liver | --- 2. Acute and late ride effects in radiotherapy | Characteristic | Acute Side Effeurs | Late Side Effects | |---|---|---| | Timing | During or shortly after treatment | Develop months or years later | | Duration | Short-term (weeks or months) | Long-term or permanent | | Affected tissues | Fast-growing cells | Slow-growing allS | | Severity | mild to moderate | Can be severe and lusting | | Examples | Skin redness, hair loss | Fibrosis, organ damage | 3. The Bath and Shower Effect in radiobiology is difference on how calls respond to radiation depending on whether the radiation is delivered in a single large dose or in smaller, repeated * Bath Effect: When a large dose of radiation is given all at once, the cells are exposed to a high dose in one go which con cause a lot of damage because the radiation affects a wider volume of tissue * Shower Effect: When radiation is spread out over time in smaller doses; the damage is more concentrated in specific regions which can result in intense localized harm the cells in irradiated grey do not have sufficient time to repair the damage before the next dose is delivered. --- 4. Survival curves for normal alls with different radiosensitivity. The graph shows survival rate versus the radiation dose in Gy late sphase has the highest survival rate compared with all the others. The shows the relationship between radiation dove and single cell survival across different phases of the cell cycle showing how call sensitivity to radiation varies. Calls in M phase have a steep survival curve with no shoulder indicates high radiation sensitivity and veny little repair capacity. Similarly, alls in ar phase also display a steep curve with minimal repair capability. In contrast, cells in to early sphate exhibit moderate shoulder on suggestina the survival curve better ability to repair radiation-induced damage. Cells in Late Sphase have large shoulder which shows high capaci for repair and significant resistance To radiation. --- 5. Prodomal effects: Appear within minutes to hours after exposure and include nausea, vomiting, fatigue, anore anorexia and diarrhea. These symptoms result from initial damage to rapidly dividing cells in the gastrointestinal tract and nervous system and may laut for hours to days before a latent phase begins. Flgematological effects: At doses ranging from 1 to 10 Gy, it appears due to damage to to the bone marrow causing a drop in blood cell production. This leads to infections, bleeding, fatigue. Recovery depends on the ability of the bone marrow to heal Gastrointestinal effects: At doses of 10-20 Gy, it become severe as the lining of the gut is damaged. This results in diarrhey, dehydration and electrolyte imbalance. Recovery is unlikely due to the high risk of infections and cell death. Neurovascular effects: At doves above 20ay, it occurs causing severe brain and blood vessel damage Symptomi include contusion, seizures, logs of conciousness and brain swelling reading to death within hours to days. --- 6. Complication Normal Tissue Control Probability and inmour Control (NTCP, TCP) The image shows a graph of the relationship between the radiation dose and probability of tumor control versus normal tissue complications. --- 6. The graph darshows the relationship between Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) baved on radiation dove. TCP curve represents the chance of eliminating the tumour while the NICP curve shows the likelihood of causing damage to healthy tissues. In optimal scenario, NTCP curve is far to the right of the TCP curve meaning the tumour can be controlled with a lower dose. thar what would cause complications in healthy tissues This is ideal because it is easier to control the tumour without harming the normal tissues. The therapeutic ratio which the ratio of tumour Control to normal tissue damage is larger indicater effective treatment with fewer side effects. The risk of treatment-related complications is lower which improves patient outcomes. ``` I hope this is helpful! Let me know if you have any other questions.