Using Computed Tomography (CT) Scanning Technique in Forensic Entomology - Research Paper Example

The Effectiveness in Using Computed Tomography (CT) Scanning Technique in Forensic Entomology Introduction The use of CT scanning technique is a newly discovered method in forensic entomology. Basically, the entirety of its methods relies on identifying the kinds of insects that reside in corpses in conducting medico-legal analysis on the time of death (Johnson et al., 2012, p. 693). In addition, Johnson et al. (2012) suggest that the principles of this medico-legal method rely on the tendency of insects to flock around corpses, as well as their susceptibility to changes in temperatures, which lead to the discovery of the time of death. Although such a process receives much attention in forensic studies, there is still a need to discuss further the full range of techniques used in such a method, and it is also necessary to discuss its limitations. Accordingly, this paper attempts to address threefold aims namely, to discuss the 1) techniques used in CT scanning, 2) limitations and 3) implications of such a method in forensic investigations. The Nature and Methods of CT Scanning Technique Nature The seminal works of Keh (1985) serve as one of the pioneering studies concerning forensic entomology, and it includes the applications and scope of the said branch of medico-legal studies. Specifically, Keh (1985) defines forensic entomology as the “study of insects and other arthropods associated with certain suspected criminal events (p. 137). Although Keh (1985) states that studying the anatomical structures and transformations of insects in corpses may be the most effective way in determining the time of death, forensic entomology is not exclusive to studying insects in corpses. Instead, Keh (1985) asserts that forensic entomology may also include other animals, such as rodents, species of fish and birds, which may have attacked the corpse. Relatively, as a branch of forensic studies, forensic entomology corresponds to a range of investigations that focus on the identified species of animals residing in the body, which may provide details on the time of death. Recent studies on forensic entomology have investigated the use of specific medical instruments in enhancing the effectiveness of medico-legal investigations. Specifically, the studies by Jennings and Austin (2011) and Richards et al. (2012) focus on the viability of using the CT scanning technique in identifying the traces of specific species of animals and insects found in carcasses. In the study by Jennings and Austin (2011), primary research is conducted using the branches of the Tasmanian tree wherein they investigate the influence of woodwasps in the creation of tunnels in the tree’s decaying branches (p. 160). Through using CT scanning, the researchers were able to determine changes undergoing in the branches in relation to the existing woodwasps residing in those. Although such topic is still subject to further research, the said research leads to the proposition that CT scanning may be helpful in investigating the role of insects in decaying bodies. Aside from the use of the CT scanning technique in determining the structural changes in decaying bodies, research also found out that determining the mass of insects in corpses may help investigators determine the time of death. Specifically, in a study detailing the advantages and drawbacks of CT scanning, the said technique is proven to be effective in determining the anatomical changes of insects, particularly the Calliphora vicina as they propagate and deteriorate in corpses (Richards et al., 2012, p. 252). Specifically, the study focuses on the cuticular markings, developmental stages, size and weight of the selected specimens, which is the blowfly. In addition, the study also found out that CT scanning is effective in determining the tracing of the growth stages of insects in corpses; this information is useful in identifying the time of death. In addition, this also gives clues on the manner of death, whether the death involves specific drugs, alcohol, or is due to wounds and physical afflictions. In this case, the nature of CT scanning, as used in the study by Richards et al., (2012), revolves around its viability and effectiveness in measuring post-mortem intervals through the kind of insect species found in the corpse, as well as the structure and developmental stages undergoing on such a specimen before the body is found. Accordingly, using CT scanning for medico-legal purposes allows investigators to find clues from the anatomical structures and changes in the corpses, which are attributable to the presence of insects and animals in the carrion. Relatively, it is likely that the phases of investigations include a range of medico-legal procedures such as dissection, CT scanning, identification of insect species and recording the structural changes that occur in the body. Although those are said to be the basic procedures in forensic entomology, Johnson et al. (2012) state that there is still a need to refine the necessary procedures in conducting the CT scanning technique in forensic entomology (p. 694). The said refinement gives way to a more enhanced manner of operation, particularly in the light of investigating crime scenes. Methods In the study by Amendt et al. (2007), the methods in the CT scanning technique include five stages (pp. 91-95). Specifically, those methods correspond to the standards set by the European Association of Forensic Entomology (EAFE) and other international forensic entomology associations. Preparing and Analyzing the Molecular Structure of the Specimen. According to Amendt, Krettek, and Zehner (2004), this stage of the CT scanning technique goes along with the long-standing ecological theory that insects, particularly blowflies, tend to swarm and propagate in carrion (p. 53). Specifically, insects may swarm over the carrion minutes after death. Further, Amendt et al. (2004) state that temperature is a significant factor in determining postmortem intervals, considering that flesh deteriorates more rapidly in warmer temperature while it also tends to decompose slowly in cooler temperatures. Additionally, in this stage of the CT scanning technique, forensic entomologists make use of a fully equipped medical and forensic toolbox containing the necessary tools and preservatives, such dark graphite pencils, forceps, spoons, fine paintbrushes and a fully furnished tool box (Amendt et al., 2007, p. 91). Further, the use of preservatives in this stage ensures that the specimen will remain untampered for further evaluations. Identification of the DNA. Identifying the DNA of the insects residing in the corpse is an essential process in forensic entomology, particularly in CT scanning wherein there is a need to identify the species of insects in the corpse (Amendt et al., 2004, p. 56). Specifically, this stage requires taxonomic knowledge wherein forensic entomologists should identify and catalog the molecular compositions of the insects residing in the body. This stage is necessary because molecular structures have a considerable influence on the rate of decompositions, particularly when the identified insects are known to contain molecules that could either hasten or slacken the decomposition process. Specifically, Amendt et al. (2004) mentioned that DNA isolation may include the phenol/chloroform extraction method and Chelex extraction (p. 56). This stage ensures the availability of specimen to be used in the next stage of the CT scanning technique. CT Scanning/Imaging. This method requires investigators to conduct the necessary imaging procedures to examine DNA of the insect comprehensively. In their study involving four species of maggots, Johnson et al. (2012) found out that using the appropriate CT scan machine gives a detailed three-dimensional view of the specimen (p. 694). This stage of the CT scanning technique corresponds to the need of acquiring a highly reliable and authentic data concerning the specimen because such data may be used for legal purposes, particularly in deaths involving crimes. Further, in the imaging stage, investigators should also consider archiving their results, particularly the molecular structures of the species, as well as the specific parts of the carcass wherein majority of the maggots were found. Consequently, this stage comprises the acquisition of relevant images, as well as documenting those images for further scientific and legal evaluations. Identification of the Maggot Mass in the Carcass. In the study by Johnson et al. (2012), identifying the maggot mass in the carcass helps in estimating the time of death (p. 693). Further, Johnson et al. (2012) states that this process corresponds to the natural tendency of maggots to flock on decaying flesh, particularly those flesh that do not have traces of poisonous chemicals. The said study also found out that maggot mass relates to temperature wherein the warmer the temperature, the higher the likelihood of an increased maggot mass in the carcass. This coincides with an earlier study by Deonier (1940 as cited in Keh, 1985) wherein varying temperatures affect maggot activities, particularly propagation and feeding on the carcass, which also influences the decomposition rate (pp. 141-142). Analysis of CT Scan Results. The fifth stage of the CT scanning technique is the analysis of results in relation to prior physical evidences concerning the death. Analyzing the CT scan results includes the cross-sectioning of the affected areas of the carcass while evaluating why such areas were affected. Succeeding investigations include the identification of the specific influence of the insect’s DNA on the decomposition of the corpse. The study by Van den Bulcke et al. (2009) suggests that the effectiveness in analyzing CT scan results lies in the capacity of CT scan imaging in providing a comprehensive three-dimensional view of the specimen (p. 509). Further, Van den Bulcke et al. (2009) cites that CT scan results analysis should focus on corpse-related data, such as the tissue damage, as well as insect-related data such as the molecular structures. This process ensures that investigators will develop and come up with a holistic analysis concerning the death. Limitations of the Technique However, although several researches support the effectiveness of such a method, there is still a shortage of literatures concerning the probable varying influences of the maggot specie that may reside in corpses. Further study should be conducted to evaluate the species of maggot that could either hasten, or slacken the decomposition of bodies. Accordingly, this research asserts that studying the chemical reaction that undergo during the carrion’s decomposition process is an interesting aspect to study. Relatively, the methodologies of CT scanning technique may still benefit from studies on the molecular composition of maggots that may drive the composition rate. For instance, the first stage of the CT scanning method may still benefit from more comprehensive studies on the molecular structures of different kinds of maggots. Considering that it is necessary to identify the DNA of the maggot species in the carrion, forensic entomology practitioners may still conduct further studies on the corresponding influence of different maggot DNAs. The third method is efficient enough in addressing the medical aspect of crimes, considering that investigators identify the mass of maggot residing in the body. Lastly, the last stage of the CT scanning method requires investigators to gather sufficient medical evidences to support their legal actions. However, considering that CT scanning may be unable to provide details on the manner of death, investigators may still benefit from studies concerning the relationship between the species of maggots residing in the corpse and the possible cause and manner of death. Conclusion This research focused on the specific methodologies in the CT scanning technique as used in forensic entomology. The primary principles of CT scanning may be attributable to the tendency of insects to flock in carrion and propagate there, which gives clues on the actual time of death. Accordingly, through analyzing related literatures on the topic, the researcher found out that CT scanning is effective in helping investigators unearth the time, place and manner of death, particularly deaths involving crimes. Specifically, aside from autopsy, the CT scanning technique is useful in estimating postmortem time and the possible cause of deaths. The methods in CT scanning includes the preparation of the specimen, conducting the CT scanning procedure, identification of the insect species in the carrion, analysis of DNA and analysis of results. The EAFE recommends that investigators should follow those procedural standards to ensure the validity of the results, once those are presented in legal analysis. Conclusively, through the related literatures studied in this paper, this research asserts that the CT scanning technique is reliable enough in providing scientific and actual data on death-related cases, particularly in the medico-legal analysis. The said method may serve as a reliable tool in gathering medico-legal evidences that could pinpoint the cause, place, time and manner of death. References Amendt, J., Campobasso, C. P., Gaudry, E., Reiter, C., LeBlanc, H. N., & Hall, M. J. R. (2007). Best practice in forensic entomology--Standards and guidelines. International Journal of Legal Medicine, 121, 90-104. doi: 10.1007/s00414-006-0086 Amendt, J., Krettek, R., & Zehner, R. (2004). Forensic entomology. Naturwissenschaften, 91, 51-65. doi: 10.1007/s00114-003-0493-5 Jennings, J. T., & Austin, A. D. (2011). Novel use of a micro-computed tomography scanner to trace larvae of wood boring insects. Australian Journal of Entomology, 50, 160-163. doi:10.1111/j.1440-6055.2010.00792.x Johnson, A., Archer, M., Leigh-Shaw, L., Pais, M., O’Donnell, C., & Wallman, J. (2012). Examination of forensic entomology evidence using computed tomography scanning: Case studies and refinement of techniques for estimating maggot mass volumes in bodies. International Journal of Legal Medicine, 126, 693-702. doi: 10.1007/s00414-012-0716-4 Keh, B. (1985). Scope and applications of forensic entomology. Annual Review of Entomology, 30, 137-154. Richards, C. S., Simonsen, T. J., Abel, R. L., Hall, M. J. R., Schwyn, D. A., & Wicklein, M. (2012). Virtual forensic entomology: Improving estimates of minimum post-mortem interval with 3D micro-computed tomography. Forensic Science International, 220, 251-264. doi:10.1016/j.forsciint.2012.03.012 Van den Bulcke, J., Boone, M., Van Acker, J., Stevens, M., & Van Hoorebeke, L. (2009). X-ray tomography as a tool for detailed anatomical analysis. Annals of Forest Science, 66, 508-520. doi: 10.1051/forest/2009033 Read More